Please read my post on The Las Vegas Stylings of Science before you read this one–it relies on it heavily.
In January 1991 I heard Al Gore give his Global Warming talk. It was in PowerPoint then too. It was at a meeting of environmental statisticians in New Orleans. Of course, then, Brother Gore’s hockey stick graph was a little shorter and we had not had the hot 90’s to add to his arsenal. He was stumping for a possible presidential run, but because he was recovering from his son’s nearly fatal accident he would choose not run that election year.
Interestingly, that same day, in fact just a few hours earlier, a statistician from the Woods Hole Marine laboratory gave a presentation saying based on his analysis of water temperature he did not think that global warming was a real. He put his skepticism that global warming in terms of a probability: it was only about 30% likely. His opinion was didn’t think it was real.
We all sort of felt bad when Al included old information on sea temperatures that had been refuted earlier that very day. At that conference Global warming was the topic of hot discussions in the hallways and lunch tables of the meeting. I would say among the scientists I talked to, most of who were actively researching the topic, it was running about the same: 30% had data and analysis supporting it, and the rest were seeing things that made them skeptical. Odds of global warming being a real phenomenon based on an informal poll of the researchers? About 3:1 against. Global warming studies were just getting off the ground in a big way in the early nineties and despite the long time Al Gore had been talking about it, the data just were not in. I didn’t care enough to feel strongly one way or the other. I was working on an EPA study on the state of the nation’s ecosystems and there were plenty of other worries to occupy my growing list of environmental concerns. Global warming, which had at the time mounds of conflicting data, had not been moved up on my list by attending this New Orleans meeting (I did shake Al’s hand and would of voted for him if he would have run. It was rare to see a candidate with such a keen mind and so scientifically literate). Most of the scientists in 1991 were unconvinced by the data supporting global warming.
That’s all changed. As studies proceeded, the evidence began to accumulate. It was coming in from all sides: Better satellite measurements of sea temperatures and sea level measurements (these increasing in accuracy from satellite measurements), calving rates of arctic ice, melting glaciers being reported worldwide from the Urals to the Andes, permafrost melting in Canada, Alaska, Siberia. The first evidence that the salinity was changing in the great sea pump that has driven the Gulf Stream for 100,000s of years came in. Moreover ecological studies of multiple species, were showing world wide habitat and range redistributions, birds were nesting earlier worldwide, coral reefs were dying in ways never seen in human history. Tropical diseases were moving out of their traditional ranges–moving northward and to higher elevations. And we began to understand why better. Ice core data 100,000 years old began to connect the dots between our actives and climate. Our computer simulation models were beginning to get better and better and we began understanding what was driving these changes. Humans. (By the way, I do ecological simulations for a living. I write about the philosophy of their use. These climate models are some of the best in the business. They are an important tool in sciences arsenal of information interpretation. These are often a point of attack from the nay-sayers.) The data for these changes was getting clearer and clearer as data became more abundant. Here’s the link to the Woods Hole’s take on climate change now.
Scientists have changed their minds. As economist John Maynard Keynes said to the charge he was flip-flopping: “When the facts change, I change my mind. What do you do, sir?”
(We now call it climate change, because people kept pointing out that it snowed a lot this year or was colder this winter than ever before thus is Global Warming refuted! It’s the poles and alpine regions that are now baring the brunt of the warming and it’s causing climate redistributions world-wide. Rain in places it doesn’t rain. Cool in warm places. Drought where it usually rains, rain where it is dry. Climate change is a more descriptive change than Global Warming.)
Plus we understood why it was happening. If an advanced space race ever came to our planet and said. “Hey guys this planet is perfect! Let’s move in! Only . . . it’s about four degrees too cold!”
“Dang. Too bad. Wait!. The crust if full of organic hydrocarbons, if we took those and put them in the atmosphere we could greenhouse it up to the perfect temperature.”
“Make it so.” their glorious leader would say.
And it would work.
Now the scientific community is nearly unanimous in its assessment (For a summery of this click on the UN’s intergovernmental panel right) In addition, it’s running at well over 50:1 in the scientific literature by my count in favor of human-caused climate change. In the peer review literature, mind you, and that’s all I count as science. And this is my most important point so I’ve underscored it for your connivence: Science requires publication in the peer reviewed journals. The papers by think-tanks, writers like Michael Crichton do not count (I only read his book Prey which so misunderstood evolution and natural selection I never went back to him) and economists and others who look at the simulations and engage in that Humean skepticism I talked about last post. I haven’t seen a negative study in years in a respected peer review journal. When there wasn’t data. Scientists disputed it. Now it is consensus. That’s the way science works. Of course, I’m sure some of you could point out a study or two. There are always holdouts. Richard S. Lindzen, comes to mind. Of course, There were still people writing against and disputing continental drift well into the 80s.
Why doesn’t everyone believe in it? I shouldn’t say ‘everyone’ I should say mostly Americans. Here in Europe they’ve been convinced by the scientific evidence and even among the hoi polloi it’s taken as a fact. Climate change skepticism is more an American (although there are exceptions) phenomenon. Why? There are lots of explanations. First Climate change in the US became politicized. It was seen as a political stance rather than a scientific one. Next, there were big interests to keep the pot stirred. A year or so ago there was a nice Newsweek article that followed the money from Big Oil to the efforts to keep Climate Change perceived as an uncertainty in the US. It was reminiscent of Tobacco company efforts to keep smoking and cancer separated by attacking the studies. But I hate to descend into conspiracy theories when the science is as strong as it its. (But hey, the most powerful economic force in the world has a vested interest in there not being global warming—do you think there is a connection? We can always trust the most powerful lobbies on Earth right?)
Second, the average citizen has trouble distinguishing peer-reviewed science from the numerous articles that are written to cast doubt on climate change. Then, of course, there are the lists of distincuished physisists, economists, dog catchers, etc. who don’t believe in human caused climate change. These are meaningless. I could sign a list saying I thought string theory was great, but it wouldn’t mean much just because I, a scientist signed the statement, I’m not a physicist. There has to be relevancy (See Project ‘Steve’ if you want to see these lists being made fun of, its a list of scientists named Steve who believe in evolution (and yes I’m there!)). The internet is chalk full of official sounding articles from impressive credentials who play the language game of science without the substance thereof. Peer review is the key to science. Without it, it’s not science. If you want a good quick assessment f\of what peer review is saying on Climate Change, look in the journals Science and Nature. These are highly respected journals where much of the Global warming debate has played out. Because the articles are written in such a way that any discipline should be able to read them they tend to be highly understandable, even the deeply technical stuff. You can actually follow the debate (when it was a debate) from the 80’s to the present and get an idea of how science plays out.
So is there a chance that global warming is not happening. Sure. But you are running at 50:1 odds at best, maybe even 500:1 odds (could only find a handful of articles doubting human caused global warming in peer reviewed literature) so I’m being very conservative in my estimate of the odds reflected in the peer reviewed literature. That’s not a very good bet. (But, hey, people still play the lottery.) You don’t have to believe in global warming, just don’t think current Science backs you up. And maybe, just maybe, it’s time to update your probabilities: “When the facts change, I change my mind. What do you do, sir?”
Next time we’ll talk about the ethics of action.
P.S. Just a reminder, I’m in Vienna and I have to approve comments (don’t worry I still approve them if you disagree with me–just not if they are angry, vitriolic, swearing, irrelevant rants (I think I’ve only not approved one comment on this entire site so far) and it’s bed time here and they might not appear until morning and they might in general seem slow to show up because of the time difference. I’m not dissing you if they don’t appear quickly, I’m just asleep.