Scientific understanding of the role of humans in influencing and altering the global climate has been evolving for over a century. That understanding is now extremely advanced, combining hundreds of years of observations of many different climatic variables, millions of years of paleoclimatic evidence of past natural climatic variations, extended application of fundamental physical, chemical, and biological processes, and the most sophisticated computer modeling ever conducted.
There is no longer any reasonable doubt that humans are altering the climate, that those changes will grow in scope and severity in the future, and that the economic, ecological, and human health consequences will be severe. While remaining scientific uncertainties are still being studied and analyzed, the state of the science has for several decades been sufficient to support implementing local, national, and global policies to address growing climate risks. This is the conclusion of scientific studies, syntheses, and reports to policymakers extending back decades.
Because of the strength of the science, and the depth of the consensus about climate change, the scientific community has worked hard to clearly and consistently present the state of understanding to the public and policymakers to help them make informed decisions. The scientific community does this in various ways. Individual scientists speak out, presenting scientific results to journalists and the public. Scientists and scientific organizations prepare, debate, and publish scientific statements and declarations based on their expertise and concerns. And national scientific organizations, especially the formal “Academies of Sciences,” prepare regular reports on climate issues that are syntheses of all relevant climate science and knowledge.
The number and scope of these statements is impressive. Not a single major scientific organization or national academy of science on earth denies that the climate is changing, that humans are responsible, and that some form of action should be taken to address the risks to people and the planet.
This consensus is not to be taken lightly. Indeed, this consensus is an extraordinarily powerful result given the contentious nature of science and the acclaim that accrues to scientists who find compelling evidence that overthrows an existing paradigm (as Galileo, Darwin, Einstein, Wegener, and others did in their fields).
In a peculiar twist, some have tried to argue that acceptance of the strength of the evidence and the massive consensus in the geoscience community about human-caused climate change is simply “argument from consensus” or “argument from authority” – a classic potential “logical fallacy.” Indeed, the mere fact that nearly 100 percent of climate and geoscience professions believe humans are changing the climate does not guarantee that the belief is correct. But arguing that something is false simply because there is a strong consensus for it is an even worse logical fallacy, especially when the consensus is based on deep, extensive, and constantly tested scientific evidence.
In fact, this false argument has a name: the Galileo Gambit. It is used by those who deny well-established scientific principles such as the theory of climate change as follows: Because Galileo was mocked and criticized for his views by a majority, but later shown to be right, current minority views that are mocked and criticized must also be right. The obvious flaw in the Galileo Gambit is that being criticized for one’s views does not correlate with being right – especially when the criticism is based on scientific evidence. Galileo was right because the scientific evidence supported him, not because he was mocked and criticized. The late professor Carl Sagan addressed this use of the Galileo Gambit in a humorous way when he noted:
“But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown.” (Broca’s Brain, 1979)
These statements and declarations about climate change by the world’s leading scientific organizations represent the most compelling summary of the state of knowledge and concern about the global geophysical changes now underway, and they provide the foundation and rationale for actions now being debated and implemented around the world. The world ignores them at its peril.
The comprehensive list has just been published at my National Geographic ScienceBlogs site, based on information available as of early January 2017. That column provides a synthesis, listing, and links for the public positions and declarations for more than 140 of the planet’s top scientific health, geosciences, biological, chemical, physical, agricultural, and engineering organizations. Each statement is archived online as noted in the links. Abbreviated sections of statements only are presented, but readers should consult the full statements for context and content. Also, scientific organizations and committees periodically update, revise, edit, and re-issue position statements. Please send me any corrections, updates, additions, and changes.
A listing of global scientific, engineering, and health organizations that have issued statements on human-caused climate change (from Gleick, 2017).