A recent article in The New York Times reported on new information that sea-level rise will exceed 3 feet this century. But just as interestingly, the journalist attempted to address a point that I consider the most crucial and poorly articulated one on climate science:
Our limited ability to predict climate change outcomes is not cause for less action. Rather, it is cause for more action, due to the risk of extreme outcomes. I think we should emphasize the inherent challenge of predicting global climate as a cause for action to reduce risks, rather than downplaying our uncertainty.
Terrorism and climate change are perhaps the two greatest issues of our time with highly unpredictable outcomes, the latter having greater potential for severe, wide-ranging impacts. The unpredictability of terrorism has increased rather than diminished our level of response. If we took the same risk-averse approach to climate change, we would be mobilizing resources towards avoiding climate change many orders of magnitude greater than we are.
The evidence shows we are approaching or passing tipping points. Alas, it is extremely hard to predict when tipping points will trigger, and virtually impossible to predict what will happen after they trigger. One might read into the Times article that more research would allow us to effectively predict sea-level rise. For climate scientists to predict such things with satisfying certainty, we would need to conduct an experiment, but there’s no second Earth available to test. So we are left with modeling, which depends on extrapolating from the past, and thus the difficulty of predicting threshold changes before it’s too late.
More research is crucial for a better understanding of the risks and range of possibilities. However, the policy community should understand that we simply cannot predict a specific outcome with certainty, not with any amount of research in the case of climate change. Nevertheless, we are confident that our climate does respond to massive doses of greenhouse gases, and can pass thresholds where catastrophic changes could occur. Knowing this should motivate us to reduce our greenhouse gas emissions as insurance against catastrophic change.
Just as we intend to avoid more than X-Acto knives on airplanes through homeland security, and we buy home insurance to avoid an event we haven’t yet experienced, we should be focused on avoiding the potential for 20-plus feet of sea-level rise this century – not just what now appears to be a middle prediction of three feet.
Post by: Bronson Griscom, forest carbon scientist, The Nature Conservancy
(Photo: Bronson Griscom of The Nature Conservancy.)
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