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Graph theory

In mathematics, graph theory is the study of graphs, which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of vertices (also called nodes or points) which are connected by edges (also called arcs, links or lines). A distinction is made between undirected graphs, where edges link two vertices symmetrically, and directed graphs, where edges link two vertices asymmetrically. Graphs are one of the principal objects of study in discrete mathematics.

Definitions
Definitions in graph theory vary. The following are some of the more basic ways of defining graphs and related mathematical structures.

Graph

In one restricted but very common sense of the term, a graph is an ordered pair $$G=(V,E)$$ comprising:
 * $$V$$, a set of vertices (also called nodes or points);
 * $$E \subseteq \{ \{x, y\} \mid x, y \in V \;\textrm{ and }\; x \neq y \}$$, a set of edges (also called links or lines), which are unordered pairs of vertices (that is, an edge is associated with two distinct vertices).

To avoid ambiguity, this type of object may be called precisely an undirected simple graph.

In the edge $$\{x, y\}$$, the vertices $$x$$ and $$y$$ are called the endpoints of the edge. The edge is said to join $$x$$ and $$y$$ and to be incident on $$x$$ and on $$y$$. A vertex may exist in a graph and not belong to an edge. Under this definition, multiple edges, in which two or more edges connect the same vertices, are not allowed.

In one more general sense of the term allowing multiple edges, a graph is an ordered triple $$G=(V,E,\phi)$$ comprising:
 * $$V$$, a set of vertices (also called nodes or points);
 * $$E$$, a set of edges (also called links or lines);
 * $$\phi : E \to \{ \{x, y\} \mid x, y \in V \;\textrm{ and }\; x \neq y \}$$, an incidence function mapping every edge to an unordered pair of vertices (that is, an edge is associated with two distinct vertices).

To avoid ambiguity, this type of object may be called precisely an undirected multigraph.

A loop is an edge that joins a vertex to itself. Graphs as defined in the two definitions above cannot have loops, because a loop joining a vertex $$x$$ to itself is the edge (for an undirected simple graph) or is incident on (for an undirected multigraph) $$\{x, x\} = \{x\}$$ which is not in $$\{ \{x, y\} \mid x, y \in V \;\textrm{ and }\; x \neq y \}$$. To allow loops, the definitions must be expanded. For undirected simple graphs, the definition of $$E$$ should be modified to $$E \subseteq \{ \{x, y\} \mid x, y \in V \}$$. For undirected multigraphs, the definition of $$\phi$$ should be modified to $$\phi : E \to \{ \{x, y\} \mid x, y \in V \}$$. To avoid ambiguity, these types of objects may be called undirected simple graph permitting loops and undirected multigraph permitting loops (sometimes also undirected pseudograph), respectively.

$$V$$ and $$E$$ are usually taken to be finite, and many of the well-known results are not true (or are rather different) for infinite graphs because many of the arguments fail in the infinite case. Moreover, $$V$$ is often assumed to be non-empty, but $$E$$ is allowed to be the empty set. The order of a graph is $$|V|$$, its number of vertices. The size of a graph is $$|E|$$, its number of edges. The degree or valency of a vertex is the number of edges that are incident to it, where a loop is counted twice. The degree of a graph is the maximum of the degrees of its vertices.

In an undirected simple graph of order n, the maximum degree of each vertex is n − 1 and the maximum size of the graph is $n(n − 1)⁄2$.

The edges of an undirected simple graph permitting loops $$G$$ induce a symmetric homogeneous relation $$\sim$$ on the vertices of $$G$$ that is called the adjacency relation of $$G$$. Specifically, for each edge $$(x,y)$$, its endpoints $$x$$ and $$y$$ are said to be adjacent to one another, which is denoted $$x \sim y$$.

Directed graph

A directed graph or digraph is a graph in which edges have orientations.

In one restricted but very common sense of the term, a directed graph is an ordered pair $$G=(V,E)$$ comprising:
 * $$V$$, a set of vertices (also called nodes or points);
 * $$E \subseteq \left\{(x,y) \mid (x, y) \in V^2 \;\textrm{ and }\; x \neq y \right\}$$, a set of edges (also called directed edges, directed links, directed lines, arrows or arcs) which are ordered pairs of vertices (that is, an edge is associated with two distinct vertices).

To avoid ambiguity, this type of object may be called precisely a directed simple graph. In set theory and graph theory, $$V^n$$ denotes the set of $n$-tuples of elements of $$V,$$ that is, ordered sequences of $$n$$ elements that are not necessarily distinct.

In the edge $$(x, y)$$ directed from $$x$$ to $$y$$, the vertices $$x$$ and $$y$$ are called the endpoints of the edge, $$x$$ the tail of the edge and $$y$$ the head of the edge. The edge is said to join $$x$$ and $$y$$ and to be incident on $$x$$ and on $$y$$. A vertex may exist in a graph and not belong to an edge. The edge $$(y,x)$$ is called the inverted edge of $$(x, y)$$. Multiple edges, not allowed under the definition above, are two or more edges with both the same tail and the same head.

In one more general sense of the term allowing multiple edges, a directed graph is an ordered triple $$G=(V,E,\phi)$$ comprising:
 * $$V$$, a set of vertices (also called nodes or points);
 * $$E$$, a set of edges (also called directed edges, directed links, directed lines, arrows or arcs);
 * $$\phi : E \to \left\{(x,y) \mid (x, y) \in V^2 \;\textrm{ and }\; x \neq y \right\}$$, an incidence function mapping every edge to an ordered pair of vertices (that is, an edge is associated with two distinct vertices).

To avoid ambiguity, this type of object may be called precisely a directed multigraph.

A loop is an edge that joins a vertex to itself. Directed graphs as defined in the two definitions above cannot have loops, because a loop joining a vertex $$x$$ to itself is the edge (for a directed simple graph) or is incident on (for a directed multigraph) $$(x,x)$$ which is not in $$\left\{(x, y) \mid (x, y) \in V^2 \;\textrm{ and }\; x \neq y \right\}$$. So to allow loops the definitions must be expanded. For directed simple graphs, the definition of $$E$$ should be modified to $$E \subseteq \left\{(x, y) \mid (x, y) \in V^2\right\}$$. For directed multigraphs, the definition of $$\phi$$ should be modified to $$\phi : E \to \left\{(x, y) \mid (x, y) \in V^2\right\}$$. To avoid ambiguity, these types of objects may be called precisely a directed simple graph permitting loops and a directed multigraph permitting loops (or a quiver) respectively.

The edges of a directed simple graph permitting loops $$G$$ is a homogeneous relation ~ on the vertices of $$G$$ that is called the adjacency relation of $$G$$. Specifically, for each edge $$(x,y)$$, its endpoints $$x$$ and $$y$$ are said to be adjacent to one another, which is denoted $$x$$ ~ $$y$$.

Applications

Graphs can be used to model many types of relations and processes in physical, biological, social and information systems. Many practical problems can be represented by graphs. Emphasizing their application to real-world systems, the term network is sometimes defined to mean a graph in which attributes (e.g. names) are associated with the vertices and edges, and the subject that expresses and understands real-world systems as a network is called network science.

Computer science
Within computer science, causal and non-causal linked structures are graphs that are used to represent networks of communication, data organization, computational devices, the flow of computation, etc. For instance, the link structure of a website can be represented by a directed graph, in which the vertices represent web pages and directed edges represent links from one page to another. A similar approach can be taken to problems in social media, travel, biology, computer chip design, mapping the progression of neuro-degenerative diseases, and many other fields. The development of algorithms to handle graphs is therefore of major interest in computer science. The transformation of graphs is often formalized and represented by graph rewrite systems. Complementary to graph transformation systems focusing on rule-based in-memory manipulation of graphs are graph databases geared towards transaction-safe, persistent storing and querying of graph-structured data.

Linguistics
Graph-theoretic methods, in various forms, have proven particularly useful in linguistics, since natural language often lends itself well to discrete structure. Traditionally, syntax and compositional semantics follow tree-based structures, whose expressive power lies in the principle of compositionality, modeled in a hierarchical graph. More contemporary approaches such as head-driven phrase structure grammar model the syntax of natural language using typed feature structures, which are directed acyclic graphs. Within lexical semantics, especially as applied to computers, modeling word meaning is easier when a given word is understood in terms of related words; semantic networks are therefore important in computational linguistics. Still, other methods in phonology (e.g. optimality theory, which uses lattice graphs) and morphology (e.g. finite-state morphology, using finite-state transducers) are common in the analysis of language as a graph. Indeed, the usefulness of this area of mathematics to linguistics has borne organizations such as TextGraphs, as well as various 'Net' projects, such as WordNet, VerbNet, and others.

Physics and chemistry
Graph theory is also used to study molecules in chemistry and physics. In condensed matter physics, the three-dimensional structure of complicated simulated atomic structures can be studied quantitatively by gathering statistics on graph-theoretic properties related to the topology of the atoms. Also, "the Feynman graphs and rules of calculation summarize quantum field theory in a form in close contact with the experimental numbers one wants to understand." In chemistry a graph makes a natural model for a molecule, where vertices represent atoms and edges bonds. This approach is especially used in computer processing of molecular structures, ranging from chemical editors to database searching. In statistical physics, graphs can represent local connections between interacting parts of a system, as well as the dynamics of a physical process on such systems. Similarly, in computational neuroscience graphs can be used to represent functional connections between brain areas that interact to give rise to various cognitive processes, where the vertices represent different areas of the brain and the edges represent the connections between those areas. Graph theory plays an important role in electrical modeling of electrical networks, here, weights are associated with resistance of the wire segments to obtain electrical properties of network structures. Graphs are also used to represent the micro-scale channels of porous media, in which the vertices represent the pores and the edges represent the smaller channels connecting the pores. Chemical graph theory uses the molecular graph as a means to model molecules. Graphs and networks are excellent models to study and understand phase transitions and critical phenomena. Removal of nodes or edges leads to a critical transition where the network breaks into small clusters which is studied as a phase transition. This breakdown is studied via percolation theory.

Social sciences
Graph theory is also widely used in sociology as a way, for example, to measure actors' prestige or to explore rumor spreading, notably through the use of social network analysis software. Under the umbrella of social networks are many different types of graphs. Acquaintanceship and friendship graphs describe whether people know each other. Influence graphs model whether certain people can influence the behavior of others. Finally, collaboration graphs model whether two people work together in a particular way, such as acting in a movie together.

Biology
Likewise, graph theory is useful in biology and conservation efforts where a vertex can represent regions where certain species exist (or inhabit) and the edges represent migration paths or movement between the regions. This information is important when looking at breeding patterns or tracking the spread of disease, parasites or how changes to the movement can affect other species.

Graphs are also commonly used in molecular biology and genomics to model and analyse datasets with complex relationships. For example, graph-based methods are often used to 'cluster' cells together into cell-types in single-cell transcriptome analysis. Another use is to model genes or proteins in a pathway and study the relationships between them, such as metabolic pathways and gene regulatory networks. Evolutionary trees, ecological networks, and hierarchical clustering of gene expression patterns are also represented as graph structures.

Graph theory is also used in connectomics; nervous systems can be seen as a graph, where the nodes are neurons and the edges are the connections between them.

Mathematics
In mathematics, graphs are useful in geometry and certain parts of topology such as knot theory. Algebraic graph theory has close links with group theory. Algebraic graph theory has been applied to many areas including dynamic systems and complexity.

Other topics
A graph structure can be extended by assigning a weight to each edge of the graph. Graphs with weights, or weighted graphs, are used to represent structures in which pairwise connections have some numerical values. For example, if a graph represents a road network, the weights could represent the length of each road. There may be several weights associated with each edge, including distance (as in the previous example), travel time, or monetary cost. Such weighted graphs are commonly used to program GPS's, and travel-planning search engines that compare flight times and costs.

History
The paper written by Leonhard Euler on the Seven Bridges of Königsberg and published in 1736 is regarded as the first paper in the history of graph theory. This paper, as well as the one written by Vandermonde on the knight problem, carried on with the analysis situs initiated by Leibniz. Euler's formula relating the number of edges, vertices, and faces of a convex polyhedron was studied and generalized by Cauchy and L'Huilier, and represents the beginning of the branch of mathematics known as topology.

More than one century after Euler's paper on the bridges of Königsberg and while Listing was introducing the concept of topology, Cayley was led by an interest in particular analytical forms arising from differential calculus to study a particular class of graphs, the trees. This study had many implications for theoretical chemistry. The techniques he used mainly concern the enumeration of graphs with particular properties. Enumerative graph theory then arose from the results of Cayley and the fundamental results published by Pólya between 1935 and 1937. These were generalized by De Bruijn in 1959. Cayley linked his results on trees with contemporary studies of chemical composition. The fusion of ideas from mathematics with those from chemistry began what has become part of the standard terminology of graph theory.

In particular, the term "graph" was introduced by Sylvester in a paper published in 1878 in Nature, where he draws an analogy between "quantic invariants" and "co-variants" of algebra and molecular diagrams:
 * "[…] Every invariant and co-variant thus becomes expressible by a graph precisely identical with a Kekuléan diagram or chemicograph. […] I give a rule for the geometrical multiplication of graphs, i.e. for constructing a graph to the product of in- or co-variants whose separate graphs are given. […]" (italics as in the original).

The first textbook on graph theory was written by Dénes Kőnig, and published in 1936. Another book by Frank Harary, published in 1969, was "considered the world over to be the definitive textbook on the subject", and enabled mathematicians, chemists, electrical engineers and social scientists to talk to each other. Harary donated all of the royalties to fund the Pólya Prize.

One of the most famous and stimulating problems in graph theory is the four color problem: "Is it true that any map drawn in the plane may have its regions colored with four colors, in such a way that any two regions having a common border have different colors?" This problem was first posed by Francis Guthrie in 1852 and its first written record is in a letter of De Morgan addressed to Hamilton the same year. Many incorrect proofs have been proposed, including those by Cayley, Kempe, and others. The study and the generalization of this problem by Tait, Heawood, Ramsey and Hadwiger led to the study of the colorings of the graphs embedded on surfaces with arbitrary genus. Tait's reformulation generated a new class of problems, the factorization problems, particularly studied by Petersen and Kőnig. The works of Ramsey on colorations and more specially the results obtained by Turán in 1941 was at the origin of another branch of graph theory, extremal graph theory.

The four color problem remained unsolved for more than a century. In 1969 Heinrich Heesch published a method for solving the problem using computers. A computer-aided proof produced in 1976 by Kenneth Appel and Wolfgang Haken makes fundamental use of the notion of "discharging" developed by Heesch. The proof involved checking the properties of 1,936 configurations by computer, and was not fully accepted at the time due to its complexity. A simpler proof considering only 633 configurations was given twenty years later by Robertson, Seymour, Sanders and Thomas.

The autonomous development of topology from 1860 and 1930 fertilized graph theory back through the works of Jordan, Kuratowski and Whitney. Another important factor of common development of graph theory and topology came from the use of the techniques of modern algebra. The first example of such a use comes from the work of the physicist Gustav Kirchhoff, who published in 1845 his Kirchhoff's circuit laws for calculating the voltage and current in electric circuits.

The introduction of probabilistic methods in graph theory, especially in the study of Erdős and Rényi of the asymptotic probability of graph connectivity, gave rise to yet another branch, known as random graph theory, which has been a fruitful source of graph-theoretic results.

Representation
A graph is an abstraction of relationships that emerge in nature; hence, it cannot be coupled to a certain representation. The way it is represented depends on the degree of convenience such representation provides for a certain application. The most common representations are the visual, in which, usually, vertices are drawn and connected by edges, and the tabular, in which rows of a table provide information about the relationships between the vertices within the graph.

Visual: Graph drawing
Graphs are usually represented visually by drawing a point or circle for every vertex, and drawing a line between two vertices if they are connected by an edge. If the graph is directed, the direction is indicated by drawing an arrow. If the graph is weighted, the weight is added on the arrow.

A graph drawing should not be confused with the graph itself (the abstract, non-visual structure) as there are several ways to structure the graph drawing. All that matters is which vertices are connected to which others by how many edges and not the exact layout. In practice, it is often difficult to decide if two drawings represent the same graph. Depending on the problem domain some layouts may be better suited and easier to understand than others.

The pioneering work of W. T. Tutte was very influential on the subject of graph drawing. Among other achievements, he introduced the use of linear algebraic methods to obtain graph drawings.

Graph drawing also can be said to encompass problems that deal with the crossing number and its various generalizations. The crossing number of a graph is the minimum number of intersections between edges that a drawing of the graph in the plane must contain. For a planar graph, the crossing number is zero by definition. Drawings on surfaces other than the plane are also studied.

There are other techniques to visualize a graph away from vertices and edges, including circle packings, intersection graph, and other visualizations of the adjacency matrix.

Tabular: Graph data structures
The tabular representation lends itself well to computational applications. There are different ways to store graphs in a computer system. The data structure used depends on both the graph structure and the algorithm used for manipulating the graph. Theoretically one can distinguish between list and matrix structures but in concrete applications the best structure is often a combination of both. List structures are often preferred for sparse graphs as they have smaller memory requirements. Matrix structures on the other hand provide faster access for some applications but can consume huge amounts of memory. Implementations of sparse matrix structures that are efficient on modern parallel computer architectures are an object of current investigation.

List structures include the edge list, an array of pairs of vertices, and the adjacency list, which separately lists the neighbors of each vertex: Much like the edge list, each vertex has a list of which vertices it is adjacent to.

Matrix structures include the incidence matrix, a matrix of 0's and 1's whose rows represent vertices and whose columns represent edges, and the adjacency matrix, in which both the rows and columns are indexed by vertices. In both cases a 1 indicates two adjacent objects and a 0 indicates two non-adjacent objects. The degree matrix indicates the degree of vertices. The Laplacian matrix is a modified form of the adjacency matrix that incorporates information about the degrees of the vertices, and is useful in some calculations such as Kirchhoff's theorem on the number of spanning trees of a graph. The distance matrix, like the adjacency matrix, has both its rows and columns indexed by vertices, but rather than containing a 0 or a 1 in each cell it contains the length of a shortest path between two vertices.

Enumeration
There is a large literature on graphical enumeration: the problem of counting graphs meeting specified conditions. Some of this work is found in Harary and Palmer (1973).

Subgraphs, induced subgraphs, and minors
A common problem, called the subgraph isomorphism problem, is finding a fixed graph as a subgraph in a given graph. One reason to be interested in such a question is that many graph properties are hereditary for subgraphs, which means that a graph has the property if and only if all subgraphs have it too. Unfortunately, finding maximal subgraphs of a certain kind is often an NP-complete problem. For example:
 * Finding the largest complete subgraph is called the clique problem (NP-complete).

One special case of subgraph isomorphism is the graph isomorphism problem. It asks whether two graphs are isomorphic. It is not known whether this problem is NP-complete, nor whether it can be solved in polynomial time.

A similar problem is finding induced subgraphs in a given graph. Again, some important graph properties are hereditary with respect to induced subgraphs, which means that a graph has a property if and only if all induced subgraphs also have it. Finding maximal induced subgraphs of a certain kind is also often NP-complete. For example:
 * Finding the largest edgeless induced subgraph or independent set is called the independent set problem (NP-complete).

Still another such problem, the minor containment problem, is to find a fixed graph as a minor of a given graph. A minor or subcontraction of a graph is any graph obtained by taking a subgraph and contracting some (or no) edges. Many graph properties are hereditary for minors, which means that a graph has a property if and only if all minors have it too. For example, Wagner's Theorem states:
 * A graph is planar if it contains as a minor neither the complete bipartite graph K3,3 (see the Three-cottage problem) nor the complete graph K5.

A similar problem, the subdivision containment problem, is to find a fixed graph as a subdivision of a given graph. A subdivision or homeomorphism of a graph is any graph obtained by subdividing some (or no) edges. Subdivision containment is related to graph properties such as planarity. For example, Kuratowski's Theorem states:
 * A graph is planar if it contains as a subdivision neither the complete bipartite graph K3,3 nor the complete graph K5.

Another problem in subdivision containment is the Kelmans–Seymour conjecture: Another class of problems has to do with the extent to which various species and generalizations of graphs are determined by their point-deleted subgraphs. For example:
 * Every 5-vertex-connected graph that is not planar contains a subdivision of the 5-vertex complete graph K5.
 * The reconstruction conjecture

Graph coloring
Many problems and theorems in graph theory have to do with various ways of coloring graphs. Typically, one is interested in coloring a graph so that no two adjacent vertices have the same color, or with other similar restrictions. One may also consider coloring edges (possibly so that no two coincident edges are the same color), or other variations. Among the famous results and conjectures concerning graph coloring are the following:
 * Four-color theorem
 * Strong perfect graph theorem
 * Erdős–Faber–Lovász conjecture
 * Total coloring conjecture, also called Behzad's conjecture (unsolved)
 * List coloring conjecture (unsolved)
 * Hadwiger conjecture (graph theory) (unsolved)

Subsumption and unification
Constraint modeling theories concern families of directed graphs related by a partial order. In these applications, graphs are ordered by specificity, meaning that more constrained graphs—which are more specific and thus contain a greater amount of information—are subsumed by those that are more general. Operations between graphs include evaluating the direction of a subsumption relationship between two graphs, if any, and computing graph unification. The unification of two argument graphs is defined as the most general graph (or the computation thereof) that is consistent with (i.e. contains all of the information in) the inputs, if such a graph exists; efficient unification algorithms are known.

For constraint frameworks which are strictly compositional, graph unification is the sufficient satisfiability and combination function. Well-known applications include automatic theorem proving and modeling the elaboration of linguistic structure.

Route problems

 * Hamiltonian path problem
 * Minimum spanning tree
 * Route inspection problem (also called the "Chinese postman problem")
 * Seven bridges of Königsberg
 * Shortest path problem
 * Steiner tree
 * Three-cottage problem
 * Traveling salesman problem (NP-hard)

Network flow
There are numerous problems arising especially from applications that have to do with various notions of flows in networks, for example:
 * Max flow min cut theorem

Visibility problems

 * Museum guard problem

Covering problems
Covering problems in graphs may refer to various set cover problems on subsets of vertices/subgraphs.
 * Dominating set problem is the special case of set cover problem where sets are the closed neighborhoods.
 * Vertex cover problem is the special case of set cover problem where sets to cover are every edges.
 * The original set cover problem, also called hitting set, can be described as a vertex cover in a hypergraph.

Decomposition problems
Decomposition, defined as partitioning the edge set of a graph (with as many vertices as necessary accompanying the edges of each part of the partition), has a wide variety of questions. Often, the problem is to decompose a graph into subgraphs isomorphic to a fixed graph; for instance, decomposing a complete graph into Hamiltonian cycles. Other problems specify a family of graphs into which a given graph should be decomposed, for instance, a family of cycles, or decomposing a complete graph Kn into specified trees having, respectively, 1, 2, 3, ...,  edges.

Some specific decomposition problems that have been studied include:
 * Arboricity, a decomposition into as few forests as possible
 * Cycle double cover, a decomposition into a collection of cycles covering each edge exactly twice
 * Edge coloring, a decomposition into as few matchings as possible
 * Graph factorization, a decomposition of a regular graph into regular subgraphs of given degrees

Graph classes
Many problems involve characterizing the members of various classes of graphs. Some examples of such questions are below:
 * Enumerating the members of a class
 * Characterizing a class in terms of forbidden substructures
 * Ascertaining relationships among classes (e.g. does one property of graphs imply another)
 * Finding efficient algorithms to decide membership in a class
 * Finding representations for members of a class

Related topics

 * Algebraic graph theory
 * Citation graph
 * Conceptual graph
 * Data structure
 * Disjoint-set data structure
 * Dual-phase evolution
 * Entitative graph
 * Existential graph
 * Graph algebra
 * Graph automorphism
 * Graph coloring
 * Graph database
 * Graph data structure
 * Graph drawing
 * Graph equation
 * Graph rewriting
 * Graph sandwich problem
 * Graph property
 * Intersection graph
 * Knight's Tour
 * Logical graph
 * Loop
 * Network theory
 * Null graph
 * Pebble motion problems
 * Percolation theory
 * Perfect graph
 * Quantum graph
 * Random regular graphs
 * Semantic networks
 * Spectral graph theory
 * Strongly regular graphs
 * Symmetric graphs
 * Transitive reduction
 * Tree data structure

Algorithms

 * Bellman–Ford algorithm
 * Borůvka's algorithm
 * Breadth-first search
 * Depth-first search
 * Dijkstra's algorithm
 * Edmonds–Karp algorithm
 * Floyd–Warshall algorithm
 * Ford–Fulkerson algorithm
 * Hopcroft–Karp algorithm
 * Hungarian algorithm
 * Kosaraju's algorithm
 * Kruskal's algorithm
 * Nearest neighbour algorithm
 * Network simplex algorithm
 * Planarity testing algorithms
 * Prim's algorithm
 * Push–relabel maximum flow algorithm
 * Tarjan's strongly connected components algorithm
 * Topological sorting

Subareas

 * Algebraic graph theory
 * Geometric graph theory
 * Extremal graph theory
 * Probabilistic graph theory
 * Topological graph theory

Related areas of mathematics

 * Combinatorics
 * Group theory
 * Knot theory
 * Ramsey theory

Generalizations

 * Hypergraph
 * Abstract simplicial complex

Prominent graph theorists

 * Alon, Noga
 * Berge, Claude
 * Bollobás, Béla
 * Bondy, Adrian John
 * Brightwell, Graham
 * Chudnovsky, Maria
 * Chung, Fan
 * Dirac, Gabriel Andrew
 * Dijkstra, Edsger W.
 * Erdős, Paul
 * Euler, Leonhard
 * Faudree, Ralph
 * Fleischner, Herbert
 * Golumbic, Martin
 * Graham, Ronald
 * Harary, Frank
 * Heawood, Percy John
 * Kotzig, Anton
 * Kőnig, Dénes
 * Lovász, László
 * Murty, U. S. R.
 * Nešetřil, Jaroslav
 * Rényi, Alfréd
 * Ringel, Gerhard
 * Robertson, Neil
 * Seymour, Paul
 * Sudakov, Benny
 * Szemerédi, Endre
 * Thomas, Robin
 * Thomassen, Carsten
 * Turán, Pál
 * Tutte, W. T.
 * Whitney, Hassler

Online textbooks

 * Phase Transitions in Combinatorial Optimization Problems, Section 3: Introduction to Graphs (2006) by Hartmann and Weigt
 * Digraphs: Theory Algorithms and Applications 2007 by Jorgen Bang-Jensen and Gregory Gutin
 * Graph Theory, by Reinhard Diestel

title: Graph theory


text:
Talk:Climate change/Archive 3

2019 - The first three archives are a disaster. I've cleaned them up somewhat. Here in archive 3, a few years ago someone went back and tried to give topical headings the threads were long done. See Talk:Global_warming/Archive_1 for more details. NewsAndEventsGuy (talk) 02:04, 30 August 2019 (UTC)

Popularity Contests (started at 20:44, February 5, 2003)
Another question about endorsement by national scientific bodies. How relevant are such organizational endorsements, in light of the 1975 NAS endorsement of a looming "ice age"? --Uncle Ed
 * @Ed, Again, haven't you done enough research on how scientists base their claims to already know the answer? I believe that the discussion of a looming ice age is based not on local data (meaning, temperature records for the past 100 years), but rather on more global studies of our climate -- e.g. there has been an ice age every x number of years in the past, so we would be due for one now.  This is like saying Halley's Comet comes by ever x number of years, so it is due again now.  But what if there is some event in space that disrupts the comet's path?  That would lead to a different prediction based on a different kind of data.  I think this is the case of global warming; the theory is that it has to do with CO2 emissions that did not exist prior to the industrial revolution and whose effect, therefore, would not be found in data on earlier ice ages.  Isn't this obvious?  IF global warming theory is correct, human activity is affecting natural cycles.  The cause of the climate change is different, so the evidence is different.  And both claims could be true: based on natural cycles, we are due for another ice-age -- but due to human activity, we are experiencing global warming.

 * As I said I am not an environmental scientist so I hope others here with special knowledge will correct me if I am wrong. But note, Ed, that I am not putting ANY of this into the article.  I am not an environmental science and have not done rigorous research so I am not screwing around with the article (this was the case with my interventions in New Imperialsim, and Irish Potato Famine, in which I was active on the talk pages because I knew something about the phenomena, enough to raise what I thought were good questions, but they were not my fields of expertise so my contributions to the articles themselves were minimal).  I think that the only people who put major assertions of fact, or explanations, into an encyclopedia article are people who have the training or have done the research that qualifies them to do so. Slrubenstein 21:10, February 5, 2003

 * Actually, NAS did not predict a "looming ice age" in 1975. I've added a discussion of this to the "global warming skepticism" article, under the subhead of "global warming vs. global cooling." Sheldon Rampton -- 02:39, February 6, 2003

 * Luckily, we have a professional author helping us! I researched the quote and found that the NAS merely said, "...there is a finite probability that a serious worldwide cooling could befall the earth within the next 100 years." Apparently it was then Science magazine which turned "finite probability" (which for all I know was only 1%) into "likely". I need more help digging into this. --[[User:Ed Po

 * I know it's anectodal, but I lived through the 1970s Coming Ice Age discussion as an amateur scientist. One of the significant factors at the time was that we had observed global temperatures were dropping for 30 years.  Looking at the climb out of the Little Ice Age up to a peak and then back down was quite a concern.  Living in exported Viking country, I was aware of the reports of warmer weather around 900AD but temperature studies were few. -- SEWilco 16:04, 25 Aug 2003 (UTC)

Key Questions Structure Suggestion
I'd like to see this article restructured to address various key questions: Or some other structure... Martin
 * 1) How fast, if at all, is the globe warming?
 * 2) What are the causes of global warming?
 * 3) What are the consequences of global warming?
 * 4) What action is being taken to avert global warming?

 * Yes, these (1 and 2) would be valuable (but) It's more sane to ask what are the consequences of climate change — Preceding unsigned comment added by 142.177.82.89 (talk • contribs) 20:48, February 7, 2003 (UTC)  Parentheticals added by me, when I removed the interweaving from the prior eds comment in 2019 NewsAndEventsGuy (talk) 15:22, 29 August 2019 (UTC)

Comments by Ed
A. It seems the article pits (good) environmentalists against (bad) fossil fuel salesmen. Each side claims the scientists support their view. B. Shouldn't the article focus first on the science of the global warming issue? C. Or should it assume the truth of the global warming hypothesis? D. Or should it start with a breakdown of who believes what, and then get into the science? E. I'm willing to work with just about any outline you all want: Sheldon, Martin, Maveric -- let's come up with an outline, so we don't work at cross purposes. If you want all the hedging and scepticism in a separate article, fine. As long as (a) it's somewhere readily accessible and (b) the controversy isn't swept under the rug in a way that suggests that the Wikipedia endorses GW theory. Uncle Ed 22:09, February 6, 2003

 * Re A, And that's more or less the state of the debate, since 'global warming' is now a shibboleth. The real issue is climate change, not 'warming'.
 * Re B, No, because it's irrelevant. Both sides have made their claims and got their funding.  There is some objectivity but no one is listening to it.  It's a purely political phrase now.  Ecological and scientific interest is moving on to climate change, an entirely different and more serious issue.
 * — Preceding unsigned comment added by 142.177.82.89 (talk • contribs) 20:48, February 7, 2003 (UTC)

 * How about one article on global climate change (which documents known facts about changes in climate, without providing any explanation); one article on the theory in question (which provides an account solely of debates among scientists), and another article on the political controversy (which avoids statements by scientists but which does look at statements by environmental activists, oil company and automobile executives, and government administrations)? Slrubenstein

 * Yes, that is advisable, as they are three different issues. Climate change is the core question, and the core danger, and no one would care about 'global warming' if it didn't imply drastic climate change and sea level rise. — Preceding unsigned comment added by 142.177.82.89 (talk • contribs) 20:48, February 7, 2003 (UTC)

 * I'm not sure that it's possible to split things into facts, scientific debate, and political debate. Some scientists take money from oil companies or from environmental lobbies, and even the strongest "facts" are sometimes disputed by extremists on both sides of the argument. Any decision over when an "opinion" becomes a "fact" is going to get difficult quickly... :-( Martin

 * Okay, you are right -- and I think your proposed outline makes sense. I do think, though, that it is important in reorganizing the article to try to distinguish as best possible observed events, proposed models of and explanations for climate change, and the politics... Slrubenstein

Suggested outline

 * Rate of Global Warming
 * historical warming and cooling
 * evidence for current warning
 * predictions of future warning
 * positions of various parties (IPCC, govts, ...)

 * Causes of Global Warming
 * anthropogenic
 * cattle
 * aerosols
 * forests->grassland
 * traffic
 * natural effects
 * solar
 * volcanos

 * Consequences of Global Warming
 * flooding
 * disease
 * more extreme weather
 * better harvests in developed countries
 * desertification

 * Actions in response to Global Warming
 * Energy Efficiency
 * Renewable and Nuclear Energy
 * Transport changes
 * UNFCCC and Kyoto

 * External Links & References

Martin

 * Under causes add "plowing". Also, Are better harvests in developed countries) likely?  I think mass slaughter of all citizens of such nations by displaced and impoverished citizens of nations destroyed by climate change is much more likely, in an age of bioterror and etc. : — Preceding unsigned comment added by 142.177.82.89 (talk • contribs) 20:48, February 7, 2003 (UTC)

Consequences
Martin, I'm sure you enjoy a good joke as much as I do, but it seems that not all the "consequences" you list would be detrimental. Was this a slip, a wry jest, or what? Some scientists have said that an additional 1.0 C rise in world temperature would be good for the earth -- like the Medieval climate optimum --Uncle Ed

 * Sorry, I got a sense of humour for a few seconds there - it won't happen again!
 * I agree, though: the consequences section would have to include any theoretical bonuses that people have prophesied, as well as doom and destruction... Martin
 * most of which will be human responses to whoever is 'blamed' for climate change damage... you're talking about 3.5 billion people... : — Preceding unsigned comment added by 142.177.82.89 (talk • contribs) 20:48, February 7, 2003 (UTC)

Martin, your outline assumes implicitly that global warming would be a bad thing. You propose a section on "averting" global warming, which implies that it's a danger to be prevented. Am I reading you right? If so, where should we put in the contrary idea that 1.0 to 1.5 C of additional warming over 1999 levels would be a good thing? --Uncle Ed

 * Ed - you could put it in two places:
 * under "consequences", you can explain any positive benefits of global warming, and dispute the various negative effects.
 * under "actions", you can include the arguments made by those who oppose the various actions. For example, one section in actions will be Kyoto, which will probably want to include the position of Bush.
 * I've changed "avert" to "in response to" - you're right that "avert" is a loaded word. Martin

Perhaps you should ask the residents of island nations like Tuvalu, Barbados, and Tonga whether they think that global warming would be a good thing. soulpatch
 * Better yet Bangladesh (a hitherto-peaceful Muslim nation), or Europe, which would have temperatures like Russia or Canada if the Gulf Stream shifted, even as the rest of the world warmed up.: — Preceding unsigned comment added by 142.177.82.89 (talk • contribs) 20:48, February 7, 2003 (UTC)

 * The article should address sea level rise, particularly the question of what causes it. For example, how much sea level correlates with "greenhouse gas" emissions; also, to what extent natural glacial melting (unrelated to the greenhouse effect) is going on. --Uncle Ed

 * And, about Tuvalu, the National Tidal Facility (NTF) at Flinders University in South Australia, which is contracted under Australian aid to monitor sea level across the Pacific, shows no significant sea level rise. 1 mm a year would take 40 years to make an inch. --Uncle Ed

 * You seem to have really missed my point. You implied that there is no reason to suggest that global warming (assuming it exists) is a bad thing.  I pointed out that a lot of people most definitely have a stake in the effects of global warming (assuming it exists).  I did not address whether global warming exists or not; I simply responded to your suggestion that global warming might not be a bad thing (assuming it exists).  Discussing data about Tuvalu sea levels is not relevant to the point I was raising.

 * (Since you brought it up, it might be worthwhile to see the opposing view on the data you cited--and the NTF, by the way, is not funded by the Australian government, but receives funding through "commercial consultancies with government and industry". A member of the Tuvalu government responded to the NTF report as follows: )  There, now you have the both sides to the story.

 * Of course, none of this is germane to the discussion at hand, namely, whether anyone would consider the global warming to be a benign phenomenon.  soulpatch

Most warming before 1940?
To add into article:

 * SALLIE BALIUNAS: "...the most important feature of the temperature record of the last 100 years is that most of the warming occurred before about 1940. But most of the greenhouse gases from human activities entered the atmosphere after 1940. That means most of the temperature rise of the last 100 years that occurred early in the century did not come from greenhouse gas activities because it came before these gases existed in the atmosphere. So the recent increase greenhouse gases cannot be the cause of the half-degree Centigrade warming or so that occurred early in the 20th century. Most of this warming must have been natural."

1870 plowing gas release

 * This is absolute worthy-of-tenure-pulling nonsense. The consensus of ecologists and climate scientists is that the biggest release of greenhouse gase into the atmosphere was the 1870-1890 plowing of the Great Plains of North America - entirely consistent with the observation that most of the warming and thus the temperature rise happened early in the 20th century.  This person is clearly not qualified to discuss this issue.  In fact, most of the greenhouse gases from human activities entered the atmosphere BEFORE 1940, and only those from INDUSTRIAL activities entered the atmosphere largely thereafter.

No 1870 CO2 spike

 * (William M. Connolley 21:23 Mar 6, 2003 (UTC)) who wrote that nonsense? We have pretty good CO2 records that cover 1870-1890 and there is no big spike for this period, ergo no big (by modern industrial emission standards) CO2 release.

More Data, Please

 * (SEWilco 16:20, 25 Aug 2003 (UTC)) Well, there was a large temperature increase from 1900-1940. If it was due to plowing, please provide some sources so the article can be updated.  If someone has other info, pipe up.  WMC says there was no big CO2 spike, but it would be nice to have any info that someone does have about the increase over that period.
 * (William M. Connolley 18:32, 27 Aug 2003 (UTC)) Well, if you can't find it anywhere else, try: http://www.antarctica.ac.uk/met/wmc/misc/scibe/co2.gif.html which includes the data files used.

Go by the records

 * It's legitimate to criticize say the Kyoto Accord for not dealing with deforestation and release of soil gas due to plowing. But it is not in any way legitimate to say that global warming due to human activities is bunk 'because' of when most of it happened.  Without good records of global temperatures and greenhouse gas levels before modern times, one can only go by the records of when areas were cleared and plowed, and how much greenhouse gas that gives off.

 * (SEWilco) ''April 1, 1862: Hitched up the big ox and finally plowed the last of the new field. It was sweaty work, with an average of 83 degrees and a wet-bulb relative humidity of 74%.    Very dirty, too, with 85% of particulates being larger than 2000 microns in a NE breeze of 5 knots.  Bumped a tray, so only got 43 samples tested, which showed a CO2 release index of only 17.  The hired hand thinks that's because the last rain left the soil moisture in a range of 10-21%.  But working behind Turkey Stomper all day makes it seem likely that his usual methane emissions are the worst of it.

''

Building article

 * Alarmists in the media and the Clinton administration clearly have decided that the best way to win the global warming debate is by shouting down the opposition and demonizing them in the eyes of the public. But that is not dispassionate scientific debate; it is more like a "struggle meeting" during the Chinese Cultural Revolution. That's not how we can build a neutral Wikipedia article. --Uncle Ed

 * Ed - I've updated the structure - see above. Would that get your blessing? Martin

I'm still not too happy about the structure. It still presumes the truth of the GW theory and the "need" for a response to GW. A neutral article would first define global warming and give any evidence for it, then provide possible causes. It would also describe predicted effects (bad and good) and describe how people feel about these effects. It should then go on to list the various proposals, such as "study it a bit more till we're sure"; "assume GW is happening, is bad, and is preventable, and that the US should ratify the Kyoto Protocol"; as well as "there's not much GW going on, and another degree or so wouldn't hurt, but Kyoto would, so DON'T sign it".

There's really both a political and a scientific issue here. It would be good to separate the 2 issues. How about global warming science and global warming politics as 2 separate articles? Or let global warming be the science article, and Kyoto Protocol be the politics article?

I would just like this article to get finished without having to worry that (as Two16 hinted) someone's going to become so angry as to want to rip a hole in my body. --Uncle Ed 19:16 Feb 10, 2003 (UTC)

 * "first define global warming" - obviously. That goes in a standard intro bit
 * "give any evidence for it" - I was going to do this as part of "Rate of Global Warming". Also give any evidence against it, of course.
 * "then provide possible causes" - yep, as part of "causes of global warming" - important to emphasise that all the possible causes are only possible.
 * "also describe predicted effects (bad and good)" - under "consequences of ..."
 * "then go on to list the various proposals" - under "actions in response to". Obviously "further study" is an important action that I somehow forgot about. And it's important to note that doing nothing is an option.

It seems to me, Ed, that you're actually kind of where I am, but I think I need to do it to prove to you that it would work without underplaying your position. I'll faff around in Global warming/temp, and then you can compare before and after and see what y'all prefer. Martin

GW page long, globalwarming/temp format suggestion
The GW page is now too long (>30k; wiki issues warnings).

I propose that a number of the subsections be cut into their own pages, preferrably the more controversial ones so that the main text could perhaps stabalise... I see discussions below about a nice new logical structure but is that actually going to happen?

William M. Connolley 14:32 Feb 12, 2003 (UTC)

 * I've made a first draft of a new version (global warming/temp). Take a look, and see if you think it's logical... :) Martin

 * OK, but sections need cutting out. I've made a start by expanding, err, well essentially rewriting Historical temperature record. Skeptics may want to modify it somewhat, but note that the satellite data (and/or comparison to sfc record) stuff really deserves its own page. William M. Connolley 18:18 Feb 12, 2003 (UTC)

 * When will a decision be made between global warming and global warming/temp? SEWilco 08:24, 12 Sep 2003 (UTC)

 * Nice. I've made some changes (mostly copy+paste bits that you missed or decided to bin), but I'm not an expert, so revert heavily. I also summarised the article at the relevant part of global warming/temp - the next thing, I guess, is predicted temperature changes to deal with how the earth's temperature is likely to change in the next 150 years. Martin

Examine effects of change
Look Ed, I don't want to get combative over this, but you really, really want to step outside and take a look at the countries that are in the front line of climate change before you make those glib assertions that a degree or two of warming might be "a good thing". That sort of ignorant, Euro/US-centric comment raises hackles in a way that's difficult to express without being uncivil. I pride myself on being restrained and understanding of cultural differences, but I live in a land that is already suffering severe consequences, and while I can live with the deniers (for every man has the right to his opinion), taking it to past mere denial to a "who cares" stance makes my blood boil. Please, knock it off. Tannin 20:23 Feb 12, 2003 (UTC)

 * Sorry, Tannin. I should not have asserted that a degree or two of warming might be a good thing. Rather, I should have pointed out that some scientists have said so. I should have named them, and provided quotes and footnotes too. Moreover, the issue of how warming might affect various local areas needs to be in the article. If warming will be concentrated at the poles and Siberia, it won't hurt anyone. If, however, warming is in places which are already too warm, it obviously will hurt people! Then there's the question whether warmer air will accelerate the glacial melting (which began in the early 1800s) AND whether that will lead to sea level rise. Coastal communities and atolls will be flooded if there's too much sea level rise -- which wouldn't be good for them. How's your blood now, buddy? Cooling off? --Uncle Ed 20:34 Feb 12, 2003 (UTC)

 * Just pointing out to future readers that the above "warming in the poles won't hurt anyone" comment applies to people in general, not residents there. Using that argument is not a good idea because exposing the Arctic Ocean without its ice cover is likely to affect climate at some level (look it up, this is just a brief note for us). SEWilco

 * Only somewhat. (Not having a handy satellite or a useful historical record to go by, these determinations are difficult to make precisely!) Europe, much (but not all) of China, and (possibly) the United States are unusual in that they have particularly rich soils and (in general) ample rain. Changes in climate patterns in many other parts of the world are much less likely to be benign. Australia and the west coast of South America are cases in point. Ignorant northern hemisphere "scientists" that make "good thing" comments for the benefit of their parochial audience without being aware of this do not deserve to have their foolishness reported. Tannin

 * Well, maybe not reported as gospel. How about "exposed"? You know, I was thinking seriously about expanding the flat earth article -- just to show clearly how the idea became popular and why it was finally discarded. Just as, someday, either global warming theory or global warming skepticism will be discarded. --Uncle Ed

Antarctica increase removed
I've removed the bit in "evidence against warming" about the 25% inc in Antarctica. As it stands, its nonsense, though the follow-up isn't. But sadly the follow-up doesn't make sense without the first text. If anyone knows what the original 25% text is supposed to mean, then by all means put it back, with refs.

Cleanup and IPCC research reminder
(William M. Connolley 20:18 18 Jun 2003 (UTC)) Several edits, all tending to removed stuff that was (IMHO) unbalanced onto the skeptical side. Both Climate model and IPCC sections are really redundant as there now exist separate pages for these - so anything useful in these sections should be stripped out and put there.

While we're on IPCC, please note that (except for a few rare counterexamples) IPCC *doesn't do research itself* it synthesises other people work. So talking about IPCC running (GCM) climate models; or assembling temperature time series, is wrong.

WMO extreme weather link
I'm not sure how to include this, but the latest report from the World Meteorological Organization highlights extreme weather and links it to climate change:   http://news.independent.co.uk/world/environment/story.jsp?story=421166 Vicki Rosenzweig 16:29 3 Jul 2003 (UTC)

 * The Indep report is distinctly dodgy. See thread on news:sci.environment if you can cope... The original WMO report might be better (one hopes so). The indep didn't seem to provide a link to it, oddly enough.

WMC-Ed clarifications
(William M. Connolley 09:28, 19 Aug 2003 (UTC)) Ed, for reasons mysterious to me you re-inserted "land" before thermos. Since you're so fond of it, I've left it in, but inserted "and marine" to make it clear that both records show essentially the same trends.

You also added some nonsense about the satellites: please please take a bit more care before doing this: the satellite record doesn't start in 1975 for one; and the satellite record now shows warming at 0.7 oC / decade at the moment.

Ditto the stuff about dissing non-western T records: the marine record destroys that. Please put in some refs if you want to keep it.

I don't think the satellite thing is nonsense. Last I saw, it showed no significant warming, rather than 7.0C per century or 0.7C per decade. Please provide a reference for the latter figure, and I will also dig up a reference for "no significant warming". Perhaps it depends on who is reading the data, and what portion they're analyzin. Personally, I have to go with a linear regression on the entire available period, although I have often seen extrapolations from a short period belied by observations from following years. As you probably know, the cycles of up and down tend to dwarf other trends. --Uncle Ed 14:50, 19 Aug 2003 (UTC)

 * The actual figure quote above should be +0.07C per decade, which was the "corrected" value for satellite temperatures put forth by Wentz, et al, taking into account orbital decay of the satellites in question. However, others (Spencer of NASA) have said that the trend is still cooling if you apply Wentz's correction and others, like accounting for precession of orbits. Not quite sure what the state of the art is on this... In 2003, Wentz, et al, put out another paper re-analyzing the original satellite raw data and claimed a 0.1C per decade warming. Not sure where they published... their 1998 paper is in Nature, Feb 23rd I think. Graft 18:54, 19 Aug 2003 (UTC)

 * (William M. Connolley 22:20, 19 Aug 2003 (UTC)) Go to Spencer and Christies page at http://www.ghcc.msfc.nasa.gov/MSU/msusci.html and click on the trop piccy to get to http://www.nsstc.uah.edu/data/msu/t2lt/tltglhmam_5.1 - links availab le from hist t page. Go to the bottom of the data page and read "DECADAL TREND=  0.074   0.142   0.005" which appears to be to July 2003. This is *not* the Wentz value, its the corrected S+C value. The Mears value may be even higher. Sorry I was wrong to say 0.7 / decade: its 0.7 / century. The hist t page has the correct value on it. If you dig up a ref (please do) make sure its up to date: the MSU record is so short it varies as extra years get added (an obvious reason for not using it for trend studies... did you remember to mention that in your additions?).

Mention satellite/balloon data
(Oh good grief Ed ***go look at the marine record*** WMC) --Uncle Ed 14:56, 20 Aug 2003 (UTC)
 * 1) I think we should mention the satellite and weather balloon data. We should also clarify what height in the atmosphere these instruments measure. Also, we should discuss the discrepancy (if any) between surface data and ballon/satellite data.
 * 2) Another issue is: where on earth has the warming and/or cooling been occurring? IF, as some advocates claim, measured warming at the surface is reported almost exclusively in places which maintain their instruments poorly OR whose goverments stand to gain economically from the global warming treaty, THEN how much should scientists rely on these measurements as being objective?

 * Are you aware of any reports on the latter? Conjecture is one thing, but an actual survey would be more useful... Graft 16:07, 20 Aug 2003 (UTC)

(William M. Connolley 13:47, 21 Aug 2003 (UTC)) All of this satellite stuff belongs on the hist t record page & I shall move it there as soon as I get round to it.

(SEWilco 08:21, 12 Sep 2003 (UTC)) Satellite records which cover the recent decades are "historical"? I thought their data indicates that some processes are not understood (although not as dramatic as the indication by recent ice ages). Is all this "global warming" stuff from before 2002 "historical", and should be moved so we can study what has happened in the past two years?

 * Discussion of the temperature record belongs in the temperature record page. Don't repeat it here [WMC].

Popularity contest query
Does anyone have any information on How Many Scientists support any of the major views on global warming? That is, has there been a survey, a poll, a petition -- anything that would indicate the proportion of scientists in the climate field who agree or disagree with any of the following?
 * that the last few years are the warmest on record; or the warmest in the last 10 centuries
 * that carbon dioxide, etc. has caused a MEASURABLE warming trend
 * that solar variation or "solar variability" explains any portion of the long-term ups and downs in the temperature record
 * that there was a Medieval warm period, followed by a Little Ice Age; or that temperatures remained constant till the Industrial Revolution spewed CO2 all over

I am looking for something more than a politician's statement during a political campaign, but I'll settle for that if that's all there is... --Uncle Ed 14:04, 21 Aug 2003 (UTC)

 * that would be good to know. incidentally, the BBC frequently mention warnings global warming without the need to water it down. how much money does the US media get from oil, ed? -- Tarquin 14:13, 21 Aug 2003 (UTC)
 * Political flak is probably a much bigger factor than direct contributions. If you say unpopular things, like, "Global warming is happening and the U.S. (i.e., auto emissions) is largely to blame," then several different kinds of shit will jump up and get stuck in your blades. Anyway, I'm not interested in surveys, since they do little to discuss actual evidence. It's much more important, and interesting, to weigh actual scientific arguments, which is how this thing should really get decided. Majority rule is no way to decide scientific questions. As it is, I have it anecdotally from my friend in the EAPS department at MIT that the overwhelming majority of the people in the field agree that warming is happening, and that it is significant but there is disagreement as to the degree of human influence on it. E.g., people agree that solar variation can explain temperature fluctuations, but only a minority believe it explains variations after 1976. But, anyway this isn't a useful question to ask, because we can instead simply state -why- people would believe or disbelieve that, e.g., the temperature diverges sharply from solar activity for that period. Graft 17:15, 21 Aug 2003 (UTC)

 * There are polls and petitions but I don't know of any that are meaningful. Even your question isn't terribly meaningful: though the answer is that most climate scientists support the ipcc position (pers. comm.). But to dissect the question: most scientists know no more than the general public about global warming? Ah, you mean *climate scientists*. But few climate scientists know much beyond their speciality. But if you were to restrict yourself to those climate scientists who know or study the temperature record and attribution, then you could find out, by reading their papers. If you did that (rather than counting the news column inches devoted to various papers) you'd find most "support" the ipcc position, which is no surprise, since the ipcc position is built out of the scientific literature.

Reversion message
Reverted WMC change. (SEWilco 04:50, 25 Aug 2003 (UTC))

 * He removed a problem mentioned in Skeptical Environmentalist section and added query of who the critics are. Shouldn't all the problems remain in the paraphrase, and check the source for details of who critics are instead of asking us who the source thinks they are? Perhaps "model the cooling effects of the particles" is no longer a problem?

 * (William M. Connolley 20:14, 25 Aug 2003 (UTC)) The cooling effects bit makes no sense to me. Is it supposed to reflect someones comments on current science? If so, whose? AFAIK, current GCMs can include particulate cooling if they wish.

 * As to the critics: saying "some people say" is just weasel words. Who says it? Anyone worth reporting? If its worth including, why not find out who these people are.
 * I think that "some people" is Lindzen, who is quoted on the IPCC TAR Summary Conflict page.
 * If so, he's singular, not plural, and might as well be named. But it would be better if he (or whoever this is) were directly quoted.
 * I think it's Lomborg, in The Skeptical Environmentalist, which has been labelled "unscientific". If it's the source, I do think the whole paragraph should be removed, as there is no reason to quote something wrong.

 * Replaced a paragraph which both pointed out more info about the above S.K. section and which pointed out that there are problems with the summary which was inserted in its place!

 * Re-removed crude word-games that constitute an inaccurate paraphrase of IPCC with what IPCC actually say.

Structure added to Talk page
I added headers and a horizontal line or two so as to make discussions easier to find and follow. Edit whatever subjects I misinterpreted in your favorite sections; sometimes several topics are mixed together and a summary is difficult. -- SEWilco 15:57, 25 Aug 2003 (UTC)

---

Hello,

I've added a link to the very interesting Discovery of GW page, a 250,000 words account at the american Institute of Physics. Also, I updated Pr Linzen testimony before the Senate (the old link led to empty page), and I added the [testimony http://www.senate.gov/~gov_affairs/071801_karl.htm]of Pr Thomas Karl, director of the NCDC and the NOAA, before the Senate. This testimony strongly endorses the IPCC and is therefore totally unambiguous about the existence of GW. Moreover, he states that "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." -- [User:nja|nja], 23 Sep 2003

Comments are requested on a discussion of the size of this article. The discussion is taking place at Talk:Scientific opinion of global warming. -- Cyan 21:28, 26 Sep 2003 (UTC)

Quantitative reconstructions
Hi Ed. *all* quantitative reconstructions I know of show much the same. Which ones do you think show the MWP etc?

(William M. Connolley 18:50, 18 Oct 2003 (UTC)) In the absence of an answer, I've re-edited to emphasise that *all* quantitative reco's show much the same pattern.

 * (SEWilco 05:21, 4 Dec 2003 (UTC)) Something is true if nobody proves otherwise? There is a million dollars on my desk, and I hope you can't prove otherwise.

Looking through Ed's edits, I'm struck by how he always portrays this stuff in terms of a fight between enviro's and skeptics: science rarely seems to get a look in (and he never references it). In the real world, (this is my p.o.v) there are the enviro's (from Ed's definition), the science, and the skeptics (my definition) running in a rough spectrum. Wikipedia should be attempting to portray what the science says (when discussing temperature trends for example) except on occaisions were the whole story is the skueptic-enviro battle.

And on a lesser note, lets not fill the GW page with T stuff: that belongs on the T pages if at all possible.

(Now we switch to Ed Poor, with inserts by WMC): Neutrality requires that the Wikipedia not take sides in any controversy: political, religious, or scientific. Since 1990, there has a been a scientific controversy about GW. It might be fueled by politics or economics, but I'm not sure of that; I just know that scientists disagree.

 * The problem is, the assertion that there has been a scientific controversy is pov: but since its yours, you don't notice it [WMC].

Some enviros (as you call them [well, as I was careful to say you call them actually (WMC)]) seek to portray the controversy as science (their side) vs. skeptics (the other side). The popular layman's magazine, Scientific American, takes that POV. The Wikipedia cannot endorse this or any other POV, but should report that certain leaders, spokesmen or advocates deem it to be this way.

Part of science, as you probably know, is the skeptical examination of data and conclusions. At their best, scientists are willing to let others "check their work" by:
 * reviewing their raw data
 * checking their data collection and selection methods
 * going over their statistical and logical reasoning
 * trying to duplicate certain experiments

 * Agreed. Thats why its a good idea to cite sources.

Scientists are not saints; they are no more reliable or honest than appeals court judges, Wikipedia editors or bus drivers.

 * Here I disagree. Its not the scientists, but their work that is at stake. And unlike, say, judgements, science is open to continuous revision.

To prevent interested parties from "cheating", there must be checks and balances, such as peer review (which is in itself imperfect) but mostly open review by the entire body of the world's scientists.

I respect your scientific work, William, and I'm glad you're involved with Wikipedia. I make many mistakes (some of which you have kindly corrected for me).

As for the "all reconstructions" thing, a quick web search will turn up the IPCC's former dataset, the one which included the Maunder Minimum, the medievel warm period and little ice age -- I'm not sure of the capitalization of those terms at Wikipedia.

A few years ago, they decided to stop using the dataset which showed the ups and downs, and decided to go with the Hockey Stick. I'm not sure why, but I have my suspicions. --Uncle Ed 15:58, 20 Oct 2003 (UTC)

 * Ed, this is silly. Read: Temperature record of the past 1000 years - apge that you have been involved in (I renamed it from hockey stick graph). The dataset which you have failed to cite is not a dataset at all: its a qualitative reconstruction. So you are *still* wrong. Please don't re-insert your changes till you can find an actual real genuine reference to what you need.

 * I agree that it's silly. I fail to grasp the difference between a 'dataset' and a 'qualitative reconstruction'.

 * (William M. Connolley 19:12, 20 Oct 2003 (UTC)) Its the difference between qualitative and quantitative (which I hope I don't have to explain). The figure you (and Daly) are so fond of is qualitative: you start off "knowing" that you want the LIA to be cold, and MWP to be warm, and a few other incidents, and you draw a rough graphs with wiggles in the right places. Thats why IPCC '90 called is "schematic", and perhaps I shold have stuck to using their word. The Mann etc *quantitative* reconstructions start off with time series of T (or proxies thereof) and combine them to produce temperature graphs. This is the essential difference. Perhaps I'll look at the GW text again to try to make this clear.

 * I don't care which term the article uses. What I meant is that the 'hockey stick' graph has replaced the 'up and down' graph. One POV is that there was no good scientific reason to conceal the ups and downs. That POV should be in the article. Another POV (perhaps yours?) is either (a) that there never was an up and down graph or (b) that there was one, but the IPCC had a good scientific reason to stop using it.

 * The "up and down" graph was replaced because there was no real quantitaive data behind it. It was never comparable with those used in the TAR which is why (once again) it was labelled schematic. Of course, Daly won't tell you that.

 * No matter what, the POVs of the various sides about the selection and presentation of temperature info (and graphs of that info) should be in the article. --Uncle Ed 17:33, 20 Oct 2003 (UTC)

 * I'm not sure I agree about this either. You don't get included in the article because you have some POV about GW, you need something to back it up.

Difference between Qualitative and Quantitative
Thank you for your quick and courteous replies, Dr. Connolley. Actually you do have to explain the difference between 'qualitative' and 'quantitative' in this context. The article is for laymen (non-scientists like me). I'm confident that you're making a critically important distinction there, but I'm failing to grasp it. (It's kind of like the 'internal' and 'external' factors thing -- and what's that other climate buzzword? 'radiative forcing' -- these terms mean nothing to our readers).

One place where we have always agreed, is that when advocates like Daly "don't tell us" something crucial, that "something" needs to go into the article. I don't want any one-sided argumentation in Wikipedia's science articles -- not even if it supports "my" POV :-)

(I will address your other points later - I'm in the middle of something that's dividing my attention, but I wanted to start acknowledging our points of agreement right away ^_^

--Uncle Ed 19:26, 20 Oct 2003 (UTC)

Majority of scientists subscribe to Warming
Could it please be stated prominently that the (vast?) majority of scientists in the field are indeed subscribers to "global warming" and "greenhouse gasses" - this information shouldn't be sidelined into a seperate scientific opinion of global warming article. Evercat 16:54, 22 Oct 2003 (UTC)

 * I would prefer to see something like environmentalists endlessly repeat their claim that the vast majority of scientists in the field are subscribers, etc. -- this point is the single biggest bone of contention in the entire global warming controversy. I have yet to see a survey whose results were other than a 50-50 split; that's not a consensus that "the science is settled".

 * Evercat, we're dealing with two radically different POVs. One says the science is settled and there's a consensus in favor of the global warming hypothesis. The other says (a) no, the science is not settled, AND (b) there is no scientific consensus regarding the issue. --Uncle Ed 21:02, 23 Oct 2003 (UTC)

Well. Can the actual scientist, William M. Connolley, please comment on this? :-) Evercat 21:06, 23 Oct 2003 (UTC)

 * (William M. Connolley 09:59, 30 Oct 2003 (UTC)) I was going to comment on this earlier but forgot: all this would be better in the sci op of cl ch page. My POV is that the vast majority of scientists support the IPCC consensus, because their work is summarised there - thats what IPCC is. But Ed insists on the Black Helicopters, sadly.

NASA on 8x Arctic warming
So, no doubt you're all aware of this already, but there's a new NASA satellite study out on arctic warming, purporting to show that warming in the Arctic has been eight times higher than that recorded by ground measurements. Rapid ice retreat, etc., also documented. Bully for them. Meanwhile, I must suffer in Boston through near-record-low temperatures. Mrrghrrfrggrggg... Graft 17:19, 24 Oct 2003 (UTC)

 * Thanks, Graft. Now all we need is an article on the North Atlantic Oscillation. --Uncle Ed 21:43, 24 Oct 2003 (UTC)

Messy article structure
So, to all you pro- and anti-global-warming types, while I appreciate the back-and-forth and think it probably results in a more robust spread of ideas and counterpoints, it also means the article is going to look like shit if people keep inserting arguments randomly into the mix. Can people try to think about the structure of the article and finagle new information into it in a non-cut-and-paste fashion? If this article is choppy and unreadable it's no help to anybody. And I think it's safe to say no magic day when everything is "settled" is going to arrive, so we need to be keeping the house tidy as we go, hey? Graft 04:30, 30 Oct 2003 (UTC)

Revert to Quant vs Qual
(William M. Connolley 09:59, 30 Oct 2003 (UTC)) Revert Ed's changes re qual/quant. Ed: if you think there are quant records that support your POV you need to find them *before* editing this page. And, if the link to the (unwritten) sargasso page is any guide to your intentions, do please remember that its a single point, *not* a reconstruction of the NH record...

As to the satellite stuff: I've moved that to the satellite T page, where it belongs. Sigh.

 * I'm not going to un-revert your changes, Dr. Connolley. If you think the info serves our readers better at the T page, so be it.

 * [WMC] I think its far more in context there.

 * Anyway, my latest research area is the Urban Heat Island (UHI) effect. I want to know if any scientists have examined the temperature record to discover temperature trends in urban areas. If cities tend to heat up over time, in proportion to the logarithm of the population, that would be an interesting discovery.

 * [WMC] It might well be. Good luck. I recommend the discussion of Karl et al 1988 in Peterson 2003 - linked in heat island.

 * By the way, I think we should move heat island back to urban heat island, since that's what I keep coming across in my google searches. --Uncle Ed 20:15, 30 Oct 2003 (UTC)

 * (William M. Connolley 20:35, 30 Oct 2003 (UTC)) Don't look at me guv, I wasn't involved in the renaming anyway. But thanks for asking.

Reverting Ed's changes
(William M. Connolley 19:39, 4 Nov 2003 (UTC)) Ed, you've added a pile of POV stuff under a transparent disguise of removing POV. So I've reverted it, retaining only the "such an increase" which is fair enough. In detail:

 * There is no need to personalise this to Mann. I know all the skeptic websites you trawl mention no-one but Mann, but that is because they like to present a nice simple picture and don't want to confuse you by mentioing that other reconstructions support much the same picture. You however have no excuse, because these others are mentioined on the t-rec-of-last-1kyr page.

 * Stating that "environmentalists" interpret these records as such-and-such is also a travesty: *scientists* interpret them so.

 * Once again, you fall into the lets-not-bother-do-our-research-properly trap, and merely write "critics complain such-and-such". *Name them*, reference them, otherwise you're just making it up.

 * you write "records overlooked or left out by the IPCC show no such unusual trend" but as usual this is just hot air on your part: no source, no indication of which records are missing, just Eds POV: worthless.

 * I see you're still whinging that its incorrect to assert that *all* quantitative reconstructions show much the same pattern. Well, don't just whinge, *actually produce one that shows otherwise*.

 * and as for 'mumbo-jumbo like "quantitative" vs. "qualitative"' - are you trying to prove that you're innumerate?

Actually, I too would like to know what quantitative and qualitative actually mean in this context. :-) Evercat 21:28, 4 Nov 2003 (UTC)

 * [WMC] Oh dear, then I'd better expand that a bit... :-)

 * [WMC] Or maybe not: the context is the Temperature record of the past 1000 years. I think its fairly well explained there: take a look,see what you think, if its still unclear I'll expand it. Its an important distinction, for MWP/LIA type stuff.

Heh. I know what quality and quantity are, but we're talking about the quality and quantity of what? The data? Is "quantitative research" that which uses a large quantity of data, while "qualitative research" uses high quality data? The Temperature record of the past 1000 years seems to use quantitative/qualitative to mean global/local - is that the real distinction? Confused, :-) Evercat 19:28, 5 Nov 2003 (UTC)

 * Oh dear. I was hoping it was more obvious than that. No: quantitative reconstructions use proxies that can be directly, numerically, related to some measured quantity: tree-ring width, coral denisty, whatever. Qualitative recon is where you say: well the harvest was early this year, and the birds flew south late, so I guess we'll call this year "warm", but you can't really say by how much.

Qual/Quant yet again
(SEWilco 05:21, 4 Dec 2003 (UTC)) In the absence of proof against it, I've added the suppressed evidence that warming is due to flying saucers venting too much heat. No, I actually replaced the claims that somehow all numbers are producing the same results. Maybe a definition of "quantitative" is needed more than a link to it.

 * (William M. Connolley 13:40, 4 Dec 2003 (UTC)) The quant results are referenced on the 1000-y-t page, UNLIKE the nameless critics you inserted, who are completely annecdotal. So, lay off the flying saucers, go read about the various quantative reconstructions (with a dictionary to hand if necessary), and if they don't say what I've said, then put something in.

Bizzare talk.
I think some of you are confusing politics in this.

Here are too things not to forget. Global Warming is 2 words. Global, and warming. If the globe is warming, then global warming is true. Global warming is an *undeniable* fact and I can give you about 100 links to international science magazines and *SCIENCE* journals. The *human causes* of global warming are in dispute, not the warming itself. The globe warms and cools naturally to *a far* greater extent than what is happening now. The greatest cause of global warming can be proven to be simply normal climatic change.

There are some who believe that humans are *accelerating* warming. I will not go into their theories, but it's simple as that.

(William M. Connolley 18:01, 14 Jan 2004 (UTC)) If you've got science to cite, please cite it. Otherwise, you're just telling us your own opinions - fascinating to you, no doubt, but not to anyone else.

Opposing Theory
''Climate researcher Stephen Schneider, who thought in the 1970s that aerosols might lead to global cooling, has become a strong proponent of the global warming hypothesis. Atmospheric physicist Richard Lindzen and Harvard astronomer Sallie Baliunas oppose the theory.''

 * Two theories are mentioned. Which one do Lindzen and Baliumas oppose? GreatWhiteNortherner 12:08, Feb 3, 2004 (UTC)

 * L and B oppose GW (William M. Connolley 18:45, 3 Feb 2004 (UTC)).

67.170.31.123's edits
(William M. Connolley 18:45, 3 Feb 2004 (UTC))67.170.31.123 has (repeatedly) added three things of dubious merit:

 * That the recent warming trend is "illusory". This is the wrong word to express doubt, and is probably quite wrong. My impression is that "essentially no-one" disputes the warming over the last century - the doubts are about the size of the trend and the attribution. But I've added a wiki to hist t rec which is prob where that mostly belongs.

 *  YOUR IMPRESSION IS WRONG

 * (William M. Connolley 09:22, 4 Feb 2004 (UTC)) Thats nice, then how about providing some (reputable) citations for it? "essentially no-one" doesn't include the guys down in the bar. What is the source of your belief?

 * That Lomborg is "vindicated". Firstly he was careless: the link he added was orthogonal to the point. OTOH, there is a point, so I've added text. OYAH, there is a (not exactly brilliant) wiki page for BL so maybe we should omit discussion of him here and refer to that age instead?

 * The "how to lie with statistics" is just silly.

This topic is dominated by a few activists who have an agenda. Reverting back to a previous document that has not been corrupted is the only answer.

 * (William M. Connolley 09:22, 4 Feb 2004 (UTC)) Err, yes, thats exactly what we're doing to your interventions. Hadn't you noticed?

 * ps: unless you really want to remain totally anonymous, why not get yourself an account, and start to sign your comments on the talk pages? It tends to make people take you more seriously.

Thankyou William for maintaining this page in ... if not great shape, at least no worse a shape than it was in before. Tannin 10:51, 4 Feb 2004 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Climate change/Archive 3


text:
Gumby

Gumby is a cartoon character and associated media franchise created by Art Clokey. Gumby is a blocky green humanoid made of clay.

Gumby stars in two television series, Gumby: The Movie, and other media. Upon his debut in 1953, he immediately became a famous example of stop motion clay animation and an American cultural icon, spawning tributes, parodies, and merchandising.

Overview
The Gumby franchise follows Gumby's adventures through different environments and historical eras. His primary sidekick is Pokey, an anthropomorphic orange pony. His arch-nemeses are the G and J Blockheads, a pair of silent antagonistic red humanoid figures with cube-shaped heads, one with the letter G on the block, the other with the letter J. Their creation was inspired by the trouble-making Katzenjammer Kids. Other characters include Prickle, a yellow fire-breathing dinosaur who sometimes styles himself as a detective with pipe and deerstalker hat like Sherlock Holmes; Goo, a flying blue shapeshifting mermaid who spits blue goo balls; Gumbo and Gumba, Gumby's parents; and Nopey, Gumby's dog whose entire vocabulary is the word "nope". The 1988 syndicated series added Gumby's sister Minga, mastodon friend Denali, and chicken friend Tilly.

1953–1969: Origins
Gumby was created by Art Clokey in the early 1950s after he finished film school at the University of Southern California (USC).

Clokey's first animated film was a 1953 three-minute student film, titled Gumbasia, a surreal montage of moving and expanding lumps of clay set to music in a parody of Disney's Fantasia. Gumbasia was created in the "kinesthetic" style taught by Clokey's USC professor Slavko Vorkapić, described as "massaging of the eye cells". Much of Gumby's look and feel was inspired by this technique of camera movements and editing.

In 1955, Clokey showed Gumbasia to film producer Sam Engel, who encouraged him to develop his technique by animating figures into children's stories. On January 29, 1955, Clokey produced and filmed the first pilot episode starring Gumby, titled Adventures of Gumby: A Sample, but never aired.

The name "Gumby" came from the muddy clay found at Clokey's grandparents' farm that his family named "gumbo". Gumby's appearance was inspired by a suggestion from his wife, Ruth (née Parkander), that Gumby be based on the Gingerbread Man. Clokey saw the color green as both racially neutral and a symbol of life. Gumby's legs and feet were made wide to pragmatically ensure that the figure would stand up during stop motion filming. Gumby's slanted head was based on the hairstyle of Clokey's father, Charles Farrington, in an old photograph.

The pilot episode was seen by NBC executive Thomas Warren Sarnoff, who asked Clokey to make another one. The second episode, Gumby on the Moon, became a huge hit on Howdy Doody, so Sarnoff ordered a series in 1955 titled The Gumby Show. In 1955 and 1956, 25 11-minute episodes aired on NBC. In early episodes, Gumby's voice was provided by Ruth Eggleston, wife of the show's art director Al Eggleston, until 1957 when Dallas McKennon assumed the role. Al Eggleston also invented Pokey, the little orange pony who was Gumby's best friend and was introduced during the earliest episodes.

Because of its variety format, The Gumby Show features Clokey's animations plus interviews and games. During this time, the show had two successive hosts, Robert Nicholson and Pinky Lee.

In 1959, The Gumby Show entered syndication, and more episodes were produced in the 1960s. Production started in Hollywood and in 1960 moved to a larger studio in Glendora, California, where it remained until production ended in 1969. During this time, Gumby was primarily voiced by Norma MacMillan and occasionally by Ginny Tyler. The cartoon shorts introduce new characters including a blue mermaid named Goo and a yellow dinosaur named Prickle.

Several sources claim that Dick Beals also voiced Gumby in the 1960s series. However, Beals himself refuted this claim in a 2001 interview.

1982–1989: Revival
Beginning in 1982, Gumby was parodied by Eddie Murphy on Saturday Night Live. In it, when the cameras are off, the sweet Gumby reverts to his true self of an irascible, cigar-chomping celebrity who is highly demanding of the production executives. Whenever they refuse his demands, Gumby asserts his star status by saying "I'm Gumby, dammit!" in an exaggerated Jewish accent. According to Joseph Clokey, Art's son, he and Art "thought Eddie was a genius in the way he played that character". In 1987, the original Gumby shorts were released on home video. In 1988, Gumby appeared in The Puppetoon Movie.

This renewed interest led to a new Gumby Adventures series of 99 seven-minute episodes, produced for television syndication in association with Lorimar-Telepictures in 1988. Dallas McKennon voices Gumby in the new adventures, in which Gumby and his pals travels beyond their toyland setting as a musical band. Gumby Adventures includes new characters, such as Gumby's little sister Minga, a mastodon named Denali and a chicken named Tilly.

The new series includes the 1950s and 1960s shorts, with new audio. The voices were re-recorded and the music was replaced by Jerry Gerber's new synthesizer score. Legal issues prevented Clokey from renewing rights to the original Capitol Records production tracks.

1990–2021: feature film and reruns
Starting in 1992, TV channels such as Nickelodeon and Cartoon Network aired reruns of Gumby episodes. In 1995, Clokey's production company produced an independently released theatrical film, Gumby: The Movie, as the character's first feature-length adventure, with John R. Dilworth, creator of Courage the Cowardly Dog, as animation consultant. In it, the villainous Blockheads replace Gumby and his band with robots and kidnap their dog, Lowbelly. It has in-joke homages to science-fiction films such as Star Wars, The Terminator, and 2001: A Space Odyssey. In 1998, the Gumby episode "Robot Rumpus" was featured on Mystery Science Theater 3000.

On March 16, 2007, YouTube announced that all Gumby episodes would appear in their full-length form on its site, digitally remastered and with their original soundtracks. This deal also extended to other video sites, including AOL. In March 2007, KQED-TV broadcast an hour-long documentary Gumby Dharma in its Truly CA series. It details Clokey's life and work, and has new animation of Gumby and Pokey. For these sequences, animator Stephen A. Buckley voiced Gumby and Clokey voiced Pokey.

In 2012, MeTV began airing Gumby in its weekend morning animation block until the end of the year.

In 2014, the VOD service Kabillion broadcast Gumby.

In 2017, a comic series was published that seemingly takes place after the movie. The series was canceled after three issues.

2022–present: Fox ownership
In February 2022, Fox Entertainment, the TV production division of the Murdoch family's Fox Corporation, announced it had acquired the Gumby intellectual property from the estate of Art's son, Joseph Clokey, encompassing all rights including "film, TV and streaming, consumer products, licensing, publishing and all other categories", with plans to launch new series across linear and digital platforms, while adding to the classic Gumby material available on its free streaming platform Tubi. Before Fox took ownership of the series, Gumby made a cameo in the seventeenth season of The Simpsons; he appeared in the episode "The Girl Who Slept Too Little".

In June 2024, it was announced that two Gumby series are currently in the works: a 2D children's animated series titled Gumby Kids and an adult animated series. Both series will be produced by Bento Box Entertainment.

Cast

 * Ruth Eggleston: Gumby (1955–1956), Gumba (1955), Additional voices
 * Dallas McKennon: Gumby (1957, 1960–1964, 1987–1989, 1995), Pokey (1960–1969), Gumbo (1960), Prickle (1964–1969), Professor Kapp (1964–1988, 1995), Denali (1988), Nopey (1964–1969), Henry (1987 re-dubbed), Rodgy (1987 re-dubbed), Additional voices
 * Norma MacMillan: Gumby (1964–1969), Pokey (1967–1968), Goo (1964–1969), Gumba (1967–1968)
 * Ginny Tyler: Gumby (1968–1969), Gumba (1957–1962), Granny (1960–1962), Witty Witch (1960–1962), Additional voices
 * Stephen A. Buckley: Gumby (1987–1991, 1996, 2007)
 * Betty Hartford: Gumba (1956)
 * Art Clokey: Pokey (1955–1988, 1995, 2007), Prickle (1964–1969, 1987–1989, 1995), Gumbo (1955–1989, 1995), Additional voices
 * Don Messick: Henry (1963), Rodgy (1963), Additional voices
 * Paul Frees: Professor Kapp (1963), Additional voices
 * Gloria Clokey: Goo (1987–1989, 1995), Gumba (1987–1989)
 * Janet MacDuff: Gumba (1988, 1995), Granny (1988), Additional voices
 * Holly Harman: Minga (1988), Tilly (1987–1989), Additional voices
 * Hal Smith: Prickle (1964–1969), Dr. Zveegee, Nopey, Additional voices
 * Dick Beals: Naughty Boy (1960)
 * Pinky Lee: Host (1956)
 * Bobby Nicholson: Scotty McKee (host) (1956–1967)

Reception and legacy
In 1993, TV Guide named Gumby the best cartoon series of the 1950s in its issue celebrating 40 years of television.

Beginning in 1994, the Library of Congress used Gumby as a "spokescharacter" for Adventures into Books: Gumby's World, a traveling exhibition promoting the Center for the Book's national reading campaign from 1997 to 2000. By the end of the 1990s, Gumby and Pokey had also appeared in various commercials for Cheerios cereal, with Gumby voiced by Stephen A. Buckley.

On August 4, 2006, the Center for Puppetry Arts in Atlanta opened Art Clokey's Gumby: The First Fifty Years. This exhibition featured many of the original puppets and sets, along with screening of Clokey's films. This event was conceived by David Scheve of T.D.A. Animation and Joe Clokey of Premavision, and was one of several exhibits that opened around the country, celebrating the 50th anniversary of The Gumby Show. The children's book Gumby Goes to the Sun was also published that year to commemorate the anniversary. The book was originally created in the 1980s by Clokey's daughter, Holly Harman (who voiced Gumby's sister, Minga, in the 1988 series).

In 2007, the Gumby comic book series was nominated for two Eisner Awards, Best New Series and Best Publication for a Young Audience, and won the latter. A Gumby graphic novel titled Gumby: 50 Shades of Clay was released in 2017.

On October 12, 2011, a Google Doodle acknowledged Art Clokey's 90th birthday. It was composed of a toy block with a "G" and five clay balls in the Google colors. Clicking each ball revealed the Blockheads, Prickle, Goo, Gumby, and Pokey.

On December 21, 2019, Eddie Murphy reprised his role while hosting SNL during a sketch on Weekend Update.

Merchandising

The most prominent of Gumby merchandise is the bendable figure set by Lakeside Toys. Several single packs and multi-figure sets were made by Jesco (later Trendmasters), and a 50th anniversary collection. There are plush dolls, keychains, mugs, a 1988 Colorforms set, a 1995 Trendmasters playset, and a Kubricks set by Medicom. A tribute album, Gumby: The Green Album, produced by Shepard Stern, was released in 1989.

In August 2005, the first video game featuring Gumby, Gumby vs. the Astrobots, was released by Namco for the Game Boy Advance. The plot follows the Blockheads and their cohorts, the Astrobots capturing Pokey, Prickle, Goo, Gumbo and Gumba and placing them in books. With his friends and parents in trouble, Gumby sets out to rescue them and defeat the Blockheads. The game is a sidescrolling platformer, where Gumby must navigate stages to reach the end, whilst avoiding enemies, pitfalls, and defeating a number of bosses from the game's various worlds. Gumby vs. the Astrobots received generally average reviews according to Review aggregator Metacritic, with an average score of 63 out of 100, based on four reviews.

The Gumby images and toys are registered trademarks of Fox Entertainment. Premavision owned the distribution rights to the Gumby cartoons, having been reverted from previous distributor Warner Bros. Television in 2003, and had licensed the rights to Classic Media until September 30, 2012. At this time, Classic Media was officially acquired by DreamWorks Animation and branded as DreamWorks Classics, which became a subsidiary of NBCUniversal in 2016. As of April 2015, NCircle Entertainment owns home video and digital distribution rights to the cartoons.

title: Gumby