One of the emails often cited as evidence of fraud refers to a “trick” to “hide the decline”. Taken out of context, this raises reasonable questions. But if you look at the full exchange and at the “trick” and “decline” referred to, it’s not nearly as incriminating as it seems. Trick is used here colloquially to refer to a way to solve a problem, not in a deceptive sense. You can even find it in the scientific literature; trick is used in the titles of scientific journal articles in this same sense. The “decline” referred to is in reference to one series of tree ring data from 1960 to 1994, a series of data that has been deemed unreliable in the peer reviewed scientific literature. The words “trick” and “decline” do not refer to global temperature records kept by the institution, only to this specific, now deemed unreliable set of data.
Besides the data on global temperatures from the Climatic Research Unit, both NASA and NOAA have independent sets of data showing the same trend in global temperatures. NASA just announced that 2009 was the second hottest year on record, and that the first ten years of this century were the hottest decade on record. The link above also includes a great discussion of how and why we see year to year variability in temperatures; for example, why 2008 was a bit cooler. It is important to keep in mind that we are looking at trends; the cold December in much of the country, or even a cooler year like 2008, do not portend a sudden shift from climate change increasing temperatures to global cooling.
In addition to the multiple temperature records that show a warming trend, there are many different pieces of anecdotal evidence that demonstrate an upward trend in temperatures. Reductions in arctic sea ice, receding glaciers, changing migration patterns and ranges of plants and animals, and areas of expanding drought all provide additional evidence that the heat content of the earth is increasing and that the climate is changing. Can we point to one specific glacier and say, “that receding glacier is caused by climate change”? No. Nor can I definitively claim that the American robins, which once provided an annual family competition over who could spot the first one each spring, now wintering around my home in Wisconsin instead of migrating farther south are doing so just because of climate change. But these and countless other observations are exactly what scientists have been telling us for years is going to happen because of climate change; not in 10 years or 20 years, but now.
The science of climate change has been discussed in much greater detail by many people more versed in its nuances then myself. For a great summary of common arguments that climate change is a myth, and a set of reasoned responses, see this Wall Street Journal article. I would also encourage you to read more about climate science at EPA’s website or NASA’s website.
Scientific conclusions are not based on rhetoric; they are based on evidence. Citing an argument or a position without evidence is irrelevant in the world of science; it has unfortunately become commonplace in the world of politics and public discourse. And this tendency has led to a heated, partisan debate over an issue that, scientifically speaking, has largely been settled. The scientific evidence demonstrating that climate change is happening, that human activities are playing a significant role, and that the impacts of a changing climate could be very negative for humanity will never be perfect; we will never have 100% agreement among scientists as to the exact causes, the exact impacts, or the proper responses. What we have now are multiple lines of independent evidence and copious amounts of anecdotal evidence that climate change is happening and that we can, and should, do something about it. Should we ever stop asking questions about climate science? Absolutely not. But drawing conclusions without evidence to muddy the debate is an exercise in denial, delay, and distraction.
We are beyond arguing about whether this problem exists; figuring out how to address the issue is where our time and energy should now be directed. Climate change is a complex problem that requires a risk management oriented approach; there are no easy answers, and no one has all the right answers. We will make mistakes, and not everything we try will work just the way it is intended. But think of it this way; if your child or parent had a heart problem, and nine out of ten doctors you went to said “your child or parents’ best chance of survival is to get a new heart,” but one doctor said, “maybe we should just wait and see what happens, and he or she might be ok”, which option would you choose?