3 ms·
We also don't know if we'll run into any negative feedback loops that'll cause cooling, either. The Earth's climate seems to be pretty stable over the last few
by msandford 11y ago
We also don't know if we'll run into any negative feedback loops that'll cause cooling, either. The Earth's climate seems to be pretty stable over the last few million years insofar as life has been able to exist in ways that are -- in terms of microbiology, our cells machinery -- very familiar.
Given that we have record of that stability it seems likely that there are forces which push the climate towards that stability.
Of course it's impossible to know for sure either way until it happens and we witness it and write it down.
- DennisP 11y agoActually the geological history is not reassuring. There have been multiple cases where the planet warmed a little due to orbital variations, and then positive feedbacks kicked in and took it several degrees further. Feedbacks evident in the record include ice melt, methane hydrate destabilization, permafrost melt releasing CO2 and methane, forest fires caused by drought, and CO2 release from dried-out topsoil and peat bogs. A good introduction to all this is in Hansen's book Storms of My Grandchildren. It's true that the past couple million years have been relatively stable. For at least the past 800,000 years CO2 never went higher than 280ppm. But the last time CO2 was as high as now, the planet was 3 to 6 degrees C warmer, and sea levels 25 to 40 meters higher: http://www.sciencemag.org/content/326/5958/1394.abstract http://www.sciencemag.org/content/326/5958/1394.abstract