The last few weeks we've had diary after diary on global warming here, and they've generally had the same message: it's a big problem! So now that we agree that it's a problem, I think it's time to start looking for solutions. This is the first of a series of diaries that I'll be doing on solutions to global warming. This first post is actually an older post from greenState, an environmental blog created by kossacks. More to come...
One of the big problems with convincing people (and governments) that global warming is a problem is that you can't point to any specific weather event and say, "that was caused by global warming." While we know that the climate is changing due to atmospheric pollution, you can't assign causation of any single event to global climate change. Four hurricanes in Florida in one year? Record heat wave in Europe? Severe drought in the Southwest? Climate is dynamic and variable, and these could just be random variation. So, we can't blame them on global warming. At least we couldn't until now...
For the first time, researchers have actually
quantified the contribution of human-caused global warming to a specific weather event. In 2003, a killer heatwave hit Europe. 20,000 people died. It may have been the region's hottest summer in 500 years. Rather than try to "prove" that global warming caused the heatwave, researchers in Britain set out to answer this question: how much more likely was this heatwave to happen with high CO2 levels than if we hadn't changed the composition of the atmosphere?
Using models (see the article in Nature for more information; subscription required), the scientists found that the heatwave was twice as likely with current CO2 levels as it would have been before the industrial revolution. This doesn't mean that global warming caused the heatwave, but it did double the risk that it happened. As an accompanying commentary in Nature noted,
Stott and colleagues' work constitutes a breakthrough: it is the first successful attempt to detect man-made influence on a specific extreme climatic event.
What does this mean? I think two things. First, this is great ammunition for those trying to convince the skeptics that global climate change is both real and a big problem. It's one thing to talk about potential future problems like rising sea levels. But being able to argue that we've doubled the risk of killer heatwaves right now is much more powerful. Hopefully, more research will let us make similar statements about other weather events (drought, hurricanes, etc.). Those still arguing that climate science is too uncertain to take any action are dangling from a very thin rope.
But there's an even bigger implication of this research. In a terrific essay, Allen and Lord argue that just knowing that global climate change increased the risk of heatwaves makes CO2 emissions actionable in courts! As they write:
If a dice is loaded to come up six, and it comes up six, there is a clear sense in which the loading `helped cause' the result. If the loading doubles the chance of a six, it follows that half the sixes you get are caused by the loading. The question of `which sixes?' is meaningless.
And that matters because:
The French authorities estimate that the 2003 heatwave caused more than 14,000 `excess deaths' nationwide. The number for which the temperatures were the principal cause of death would be lower, but could still run into thousands. Suppose it is confirmed, at a reasonable level of confidence, that past greenhouse-gas emissions doubled the risk of these local temperature anomalies. This would surely meet or exceed the threshold at which a court might conclude those emissions were, in a loaded-dice sense, likely to have been a `legally effective' cause of death and hence that some victims might have grounds to claim compensation against those responsible for the emissions.
If, say, a relative of yours died in the French heatwave, you could concievably sue for damages because carbon emissions contributed to the death. But who would be responsible?
Preliminary studies suggest that a substantial fraction of our current elevated level of carbon dioxide might be traced to products produced, sold or used by only a few dozen major companies.
But there are problems:
As there are no direct observations of what the European climate of 2003 would have been like if greenhouse-gas emissions had not occurred, quantifying human contributions to risks will always depend on computer simulations. How would a court view this kind of evidence? In principle it should be admissible: computer simulations are not unknown in the courtroom, however unnerving climate modellers may find it to have the tools of their trade being picked over by skilled defence lawyers.
Still, this seems to me a promising avenue to pursue. Already, lawsuits targetting CO2 emitters are underway in the U.S. and abroad.
Greenpeace is involved in lawsuits accusing the U.S. Export-Import Bank of wrongly funding fossil fuel projects in poor nations and another accusing the U.S. Environmental Protection Agency (news - web sites) of failing to rein in greenhouse gases.
Low-lying Pacific island states including Tuvalu, at risk of disappearing if sea levels rise, are considering suing the United States, the world's top source of greenhouse gases, to force it to do more to curb global warming. (
link)
Odds are it will be years if not decades before anyone wins a court award for damages due to global warming. And if this strategy bears fruit, I wouldn't be surprised if Congress jumped in to stop future lawsuits related to climate change. But given that the world seems to be making little or no progress in stopping global climate change, it's nice to see one new weapon that environmentalists may be able to bring to bear in this struggle.