“Burning all fossil fuels would produce a different, practically uninhabitable, planet. …Our calculated global warming in this case is 16◦C, with warming at the poles approximately 30◦C. Calculated warming over land areas averages approximately 20◦C. Such temperatures would eliminate grain production in almost all agricultural regions in the world.”
“…More ominously, global warming of that magnitude would make most of the planet uninhabitable by humans. The human body generates about 100 W of metabolic heat that must be carried away to maintain a core body temperature near 37◦C, which implies that sustained wet bulb temperatures above 35◦C can result in lethal hyperthermia. Today, the summer temperature varies widely over the Earth’s surface, but wet bulb temperature is more narrowly confined by the effect of humidity, with the most common value of approximately 26–27◦C and the highest approximately of 31◦C. A warming of 10–12◦C would put most of today’s world population in regions with wet a bulb temperature above 35◦C.
…We conclude that the large climate change from burning all fossil fuels would threaten the biological health and survival of humanity, making policies that rely substantially on adaptation inadequate.
…Most of the remaining fossil fuel carbon is in coal and unconventional oil and gas. Thus, it seems, humanity stands at a fork in the road. As conventional oil and gas are depleted, will we move to carbon-free energy and efficiency—or to unconventional fossil fuels and coal? If fossil fuels were made to pay their costs to society, costs of pollution and climate change, carbon-free alternatives might supplant fossil fuels over a period of decades. However, if governments force the public to bear the external costs and even subsidize fossil fuels, carbon emissions are likely to continue to grow, with deleterious consequences for young people and future generations.
It seems implausible that humanity will not alter its energy course as consequences of burning all fossil fuels become clearer. Yet strong evidence about the dangers of human-made climate change have so far had little effect. Whether governments continue to be so foolhardy as to allow or encourage development of all fossil fuels may determine the fate of humanity.”
-James Hansen, Makiko Sato, Gary Russell, and Pushker Kharecha, current and former scientists at NASA’s Goddard Institute for Space Studies, in a peer reviewed scientific journal article published in 2011.