free debate

December 28, 2009

Skepticism and Climate Change

Recently there has been a lot of discussing regarding climate change within the skeptical community. Famous skeptic James Randi and science educator Johnny Ball, have both expressed their doubts as to the effect humans are having on climate change. The was a media storm as some embarrassing private e-mails between climate scientists were made public. This has raised several questions including what is the evidence for climate change and what is the role of skepticism in this issue.

Any issue that is highly politicized is hard to find good information on. We have discussed the issue of climate change a few times before on this blog (here and here) but I want to quickly review some of the science. There are several claims made with regard to climate change. The first is that the globe is, on average, warming. I think most people accept this fact. The debate is over the cause. The Earth is in a time period where we would expect to see temperatures rising naturally to a degree. The debate is over how much of the current warming trend is natural, and how much is caused by the human emissions of greenhouse gasses like CO2.

When we are dealing with an issue as complicated as climate change, we want to look at the scientific consensus. We don't want to look at the opinion of every scientist on the planet, but of those scientists who are doing work in relevant fields. The Intergovernmental Panel on Climate Change (IPCC) is a group composed of thousands of scientists from countries around the world. They have said in their most recent publication, "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG [greenhouse gas] concentrations." There is a growing amount of evidence that backs up this conclusion.

There is another debate on how we should react to climate change, but that is for a future post. My question here is what is the role of skepticism in regard to this evidence.

In science, opinions that go against the consensus play an important role. Grants will often go to people doing research that goes against the grain. I am glad that there are scientists that are working on finding problems with climate models and trying to poke holes in the other lines of evidence for climate change. This said, I think we have to remember this is a minority view.  Skepticism is about forming views based on the evidence. So far, the evidence points strongly towards a human contribution for climate change. I think that regardless of our personal viewpoints we need to respect that. I have no problem with people like James Randi expressing doubts about the human influences on the climate. I have said before skepticism is not a set of views, but a process for forming ones own views about the world. I do think though that to be responsible, leaders like Randi need to be clear that they are disagreeing with the scientific consensus. There are sill places for their doubt. We are still are developing climate models, and their are error bars for the evidence (see the image above). I don't find these arguments convincing, but others do and that's where the dialogue should be.

I personally find the evidence for the human influences on climate change overwhelming. I always welcome people to disagree with me, but please do so with evidence and logic. Recognize that the scientific community has overwhelmingly showed their support for this view. I think it is unfortunate that there are people who disagree with me based solely on its implications or for other political reasons. I have have talked with scientists on both sides of this issue, and I think that the most reasonable thing to do is respect the conclusion of the majority of working climate scientists.