Another climate change report from the "Yeah, it's way worse than you imagined" file.
Has there ever been an area of science where predictions have been so persistently unduly optimistic. Not all that long ago the really dire predictions were that, if we didn't quickly slash our emissions of greenhouse gases, thus and so might hit us by 2100. Of course that meant not us, not you and me, but maybe our grandkids or their kids. That Arctic sea ice might be gone by 2100 if we didn't change our ways. The temperature might rise by 2 degrees Celsius by 2100 if we kept gorging ourselves on fossil fuels. We might trigger feedback loops, runaway global warming, by 2100 unless we were really careful.
Okay, so here's the latest.
“The hope was that climate sensitivity was lower and the Earth is not going to warm as much,” said Cristian Proistosescu, at Harvard University in the US, who led the new research. “There was this wave of optimism.”
The new research, published in the journal Science Advances, has ended that. “The worrisome part is that all the models show there is an amplification of the amount of warming in the future,” he said. The situation might be even worse, as Proistosescu’s work shows climate sensitivity could be as high as 6C.
Prof Bill Collins, at the University of Reading, UK, and not part of the new research, said: “Some have suggested that we might be lucky and avoid dangerous climate change without taking determined action if the climate is not very sensitive to CO2 emissions. This work provides new evidence that that chance is remote.” He said greater long term warming had implications for melting of the world’s ice sheets and the rise of sea levels that already threatens many coastal cities.
Land, mostly in the northern hemisphere heats up quickly. But there is also a slow response, he said: “This is mostly associated with warming over the oceans. They are big and full of cold water, especially at depth, and take a long time to heat up.” Furthermore, when the slow warming does kick in, it is likely to reduce the cloud cover that shades the Southern ocean and the eastern tropical Pacific, amplifying the heating.
Now, here's the thing. The impacts of 4 or 5 or 6 degrees Celsius warming above pre-industrial levels are generally the same as what we'll see with 2C of warming only orders of magnitude greater in severity. For example, you'll get sea level rise only as the world gets ever hotter the seas will rise faster and higher and the losses and disruption will be more catastrophic. Floods in some places and droughts in others will have the same pattern of increased intensity, frequency and severity as temperatures rise. The deadly consequence of heatwaves will likewise just get worse and more areas will be rendered uninhabitable.
There you go, our goose is pretty much cooked. We don't have five or ten or thirty years to abandon fossil energy. As Hans Joachim Schellnhuber warned the delegates to the 2015 Paris climate summit our only chance of surviving climate change depended on our willingness to accept an "induced implosion" of our fossil fuel industries. And you know that we've never had a government - federal or provincial - in Canada onside with that notion.