So I finally got around to watching the full hour of Al Gore’s presentation during his “24 Hours of Reality” on 14 September. (Their website also has loads of other video material).
Much of it runs through recent extreme weather events and I personally could have done with a few less examples. But according to Gore scientists have made a subtle but profound change in the way that they speak about the connection between the climate and the extreme weather events. They used to say you can’t connect any extreme weather event to climate because there are multiple factors. They used to say we’re changing the odds, we’re loading the dice that make it more likely that we’ll get extreme weather events. Now the change is we’re not only loading the dice, we’re painting more dots on the dice. We’re not only rolling more 12s, we’re rolling 13s and 14s and soon 15s and 16s. And according to NASA’s James Hansen, instead of asking whether all these recent extreme weather events were caused by global warming, one might ask whether they would have occurred if atmospheric carbon dioxide had remained at the pre-industrial level of 280 parts per million (instead of rising to 390 ppm). An appropriate answer in that case is”almost certainly not”.
Gore also nicely debunks some of the arguments brought forward by climate skeptics.
There is no scientific consensus? Every national academy of science of every major country in the world confirms the science of global warming. The ones that do not agree do not exist. A joint statement of the National Academies of Science of the G8+5 countries stated that, “The need for urgent action to address climate change is now indisputable.” In addition, every single professional society in fields related to the study of climate science agrees.
Volcanoes emit many times more CO2? While volcanoes emit 0.15-0.26 gigatonnes per year humans emit 35 gigatonnes per year – 135-230 times more.
It’s the sun, stupid? Solar irradiation has actually been at a minimum over the last decades and still the hottest 10 years since measurements began were in the last 13 years. “That’s a coffin with so many nails in it already that the hard part is finding a place to hammer in a new one.”
Global warming has stopped? Every year there are high temperature records and low temperature records. While they used to balance out, now they are tilted way towards the high end, at a ratio of 50:1.
Climate science is just relying on computer models? In fact, there are a dozen separate and different lines of evidence showing significant human-caused warming. (John Cook’s amazing “Skeptical Science” website has a nice graphic going into details.)
And yet some seem certain that the world’s scientists are wrong and that emitting 90 million tonnes of CO2 into the atmosphere per day couldn’t possibly be the problem.
Gore points out that all these red herrings didn’t emerge by accident. A memo leaked to the New York Times revealed the strategy to “reposition global warming as theory rather than fact”. Just as the tobacco industry for decades downplayed evidence that smoking causes cancer.
Gore’s final call to action pleasantly focuses on the political rather than consumer choices. While these are important, “changing laws is more important than changing light bulbs. I’ve been in politics, let me tell you the secret message. Tell your leaders that you are paying attention… If you do the right thing, I’m going to help you get elected. If you don’t, I’m going to do everything in my power to get you defeated.” And people should speak up in their private lives as well and don’t let climate denial go unchallenged. “When we have made big moral choices (…) it has often been in part because average citizens spoke up.”