* Late 2008: The Hadley Centre for Meteorological Research predicts a 2C increase by 2100.
* Mid-2009: The U.N. Environment Programme predicts a 3.5C increase by 2100. Such an increase would remove habitat for human beings on this planet, as nearly all the plankton in the oceans would be destroyed, and associated temperature swings would kill off many land plants. Humans have never lived on a planet at 3.5C above baseline.
* October 2009: The Hadley Centre for Meteorological Research releases an updated prediction, suggesting a 4C temperature increase by 2060.
* November 2009: The Global Carbon Project, which monitors the global carbon cycle, and the Copenhagen Diagnosis, a climate science report, predict 6C and 7C temperature increases, respectively, by 2100.
* December 2010: The U.N. Environment Programme predicts up to a 5C increase by 2050.
* 2012: The conservative International Energy Agency's World Energy Outlook report for that year states that we are on track to reach a 2C increase by 2017.
* November 2013: The International Energy Agency predicts a 3.5C increase by 2035.
A briefing provided to the failed U.N. Conference of the Parties in Copenhagen in 2009 provided this summary: "The long-term sea level that corresponds to current CO2 concentration is about 23 meters above today's levels, and the temperatures will be 6 degrees C or more higher. These estimates are based on real long-term climate records, not on models."
On December 3rd, a study by 18 eminent scientists, including the former head of NASA's Goddard Institute for Space Studies, James Hansen, showed that the long-held, internationally agreed upon target to limit rises in global average temperatures to 2 degrees Celsius was in error and far above the 1C threshold that would need to be maintained in order to avoid the effects of catastrophic climate change.
And keep in mind that the various major assessments of future global temperatures seldom assume the worst about possible self-reinforcing climate feedback loops like the methane one.
"Things Are Looking Really Dire"
Climate-change-related deaths are already estimated at five million annually, and the process seems to be accelerating more rapidly than most climate models have suggested. Even without taking into account the release of frozen methane in the Arctic, some scientists are already painting a truly bleak picture of the human future. Take Canadian Wildlife Service biologist Neil Dawe, who in August told a reporter that he wouldn't be surprised if the generation after him witnessed the extinction of humanity. All around the estuary near his office on Vancouver Island, he has been witnessing the unraveling of "the web of life," and "it's happening very quickly."
"Economic growth is the biggest destroyer of the ecology," Dawe says. "Those people who think you can have a growing economy and a healthy environment are wrong. If we don't reduce our numbers, nature will do it for us." And he isn't hopeful humans will be able to save themselves. "Everything is worse and we're still doing the same things. Because ecosystems are so resilient, they don't exact immediate punishment on the stupid."
The University of Arizona's Guy McPherson has similar fears. "We will have very few humans on the planet because of lack of habitat," he says. Of recent studies showing the toll temperature increases will take on that habitat, he adds, "They are only looking at CO2 in the atmosphere."
Here's the question: Could some version of extinction or near-extinction overcome humanity, thanks to climate change -- and possibly incredibly fast? Similar things have happened in the past. Fifty-five million years ago, a five degree Celsius rise in average global temperatures seems to have occurred in just 13 years, according to a study published in the October 2013 issue of the Proceedings of the National Academy of Sciences. A report in the August 2013 issue of Science revealed that in the near-term Earth's climate will change 10 times faster than at any other moment in the last 65 million years.
"The Arctic is warming faster than anywhere else on the planet," climate scientist James Hansen has said...