Tuesday, October 15, 2013

Climate Sensitivity Is High, Burning All Fossil Fuels Would Make Most Of Planet ‘Uninhabitable’

If we choose to put the future of our species at severe risk, why does our species deserve to exist?


By Joe Romm on September 17, 2013

James Hansen, the country’s most prescient climatologist, is out with another must-read paper, “Climate sensitivity, sea level and atmospheric carbon dioxide.” The paper, co-authored by a number of Hansen’s former colleagues at NASA, is an antidote to the rosy scenarios the mainstream media have recently been pushing.

The key findings are

The Earth’s actual sensitivity to a doubling of CO2 levels from preindustrial levels (to 550 ppm) — including slow feedbacks — is likely to be larger than 3–4°C (5.4-7.2°F).
Given that we are headed towards a tripling (820 ppm) or quadrupling (1100 ppm) of atmospheric CO2 levels, inaction is untenable.
“Burning all fossil fuels” would warm land areas on average about 20°C (36°F) and warm the poles a stunning 30°C (54°F). This “would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.”

Burning all or even most fossil fuels would be a true scorched Earth policy.

Given that James Hansen has been right about global warming for more than 3 decades, his climate warnings need to be taken seriously.


If we stay anywhere near our current emissions path, we face catastrophic levels of warming.


Hansen et al. note that this may not even require burning all of fossil fuels. It could happen on our current emissions path — if the slower (decadal) feedbacks are as strong as some paleoclimate analysis suggests. Back in 2011 we reported on a paleoclimate paper in Science that found we are headed towards CO2 levels in 2100 last seen when the Earth was 29°F (16°C) hotter.


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