A recent review finds that over 97% of scientists believe that human activity is contributing to climate change. That is a very solid consensus of scientific opinion.
This, of course, does not mean that the consensus must be correct, but...
A recent review finds that over 97% of scientists believe that human activity is contributing to climate change. That is a very solid consensus of scientific opinion.
This, of course, does not mean that the consensus must be correct, but (along with other data) it makes it unreasonable to claim that there is no consensus, or that there is significant scientific controversy on this topic. In fact, the 97% figure exactly matches prior surveys. Many scientific organizations have also officially endorsed this consensus.
One of the common methods of deniers is to pretend as if there is a raging scientific controversy when in fact there is a solid consensus. Creationists, for example are constantly trying to portray evolution as a “theory in crisis,” when in fact it is doing quit well, thank you.
The study employed an interesting methods. They reviewed 12,000 peer-reviewed published papers on topics relevant to climate change. They then tabulated, for those papers in which the researchers expressed a clear opinion about climate change, whether or not they supported the conclusion of anthropogenic global warming. In over 97% of cases they did.
From the abstract:
We analyze the evolution of the scientific consensus on anthropogenic global warming (AGW) in the peer-reviewed scientific literature, examining 11?944 climate abstracts from 1991–2011 matching the topics ‘global climate change’ or ‘global warming’. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming.
No survey is ever perfect – whenever you evaluate a subset of people in order to draw conclusions about the larger group, there is the possibility of selection bias. In this case one might argue that scientists who reject anthropogenic global warming are less likely to express those views in a peer-reviewed paper, or to have such views published.
This method, however, is reasonable. They also backed this up with another phase of the study in which they invited authors to rate their own research and opinions, and 97.2% endorsed the consensus of global warming. While it’s possible to quibble about this number, given the strong agreements among various methods around the 97% figure, it’s difficult to argue that the true figure is significantly different.
Why do we care about the consensus? Isn’t this just an argument from authority? Well, yes and no.
It seems reasonable, especially for those who consider themselves skeptics, to argue that facts and logic should determine a scientific question, not authority. Or that we should “let the fact speak for themselves.”
Unfortunately, facts cannot speak for themselves. Scientific evidence needs to be examined, rated for quality, interpreted, and put into a broader context. There is often no simple connect from facts to conclusions in science – background knowledge, knowledge of the processes of science, familiarity with critical thinking, logical pitfalls, and the effects of bias on interpretation are all necessary to come to a reliable conclusion about what those facts are telling us.
Different individuals are likely to have different biases and knowledge bases, and therefore may come to different conclusions about the same set of data. No individual, therefore, can be the ultimate authority on any scientific question.
The power of consensus is that individual quirks and biases will tend to average out. The consensus of scientific opinion, therefore, is a way to gauge the agreement and power of the scientific evidence.
The only other alternative is to evaluate all the scientific evidence first hand and come to your own conclusion. The potential pitfall here, however, is that individuals who are not experts in the relevant field believe