Guest Post by Bob Tisdale
The 2 deg C global warming limit, above pre-industrial temperatures, is back in the news. That limit was first proposed in the 1970s by an economist, not a climate scientist, according to the article Two degrees: The history of climate change’s ‘speed limit’ at TheCarbonBrief. Authors Mat Hope & Rosamund Pearce note:
Perhaps surprisingly, the idea that temperature could be used to guide society’s response to climate change was first proposed by an economist.
In the 1970s, Yale professor William Nordhaus alluded to the danger of passing a threshold of two degrees in a pair of now famous papers, suggesting that warming of more than two degrees would push the climate beyond the limits humans were familiar with:
“According to most sources the range of variation between between distinct climatic regimes is on the order of ±5°C, and at present time the global climate is at the high end of this range. If there were global temperatures more than 2° of [sic] 3° above the current average temperature, this would take the climate outside of the range of observations which have been made over the last several hundred thousand years.”
Back in February 2015, The Guardian revealed “EU climate chief and UN’s top climate official both play down expectations that international climate talk pledges will help hit 2C target” in its article Paris climate summit: missing global warming target ‘would not be failure’. It provided the quotes:
“2C is an objective,” Miguel Arias Canete, the EU climate chief, said. “If we have an ongoing process you can not say it is a failure if the mitigration [sic] commitments do not reach 2C.”
In Brussels, meanwhile, the UN top climate official, Christiana Figueres, was similarly downplaying expectations, telling reporters the pledges made in the run-up to the Paris meeting later this year will “not get us onto the 2C pathway”.
WITH UN AND EU OFFICIALS DOWNPLAYING EXPECTATIONS FOR THE PARIS CLIMATE SUMMIT, THE CO2-OBSESSED HAVE TURNED TO THE GODFATHER OF CLIMATE ALARMISM
Of course I’m talking about James Hansen, retired former head of NASA’s Goddard Institute of Space Studies (GISS). Expectedly, global warming enthusiasts have turned once again to him for sound bites.
Hansen was recently quoted in the article Paris 2015: Two degrees warming a ‘prescription for disaster’ says top climate scientist James Hansen at The Age. The article by Peter Hannam begins:
The aim to limit global warming to two degrees of pre-industrial levels is “crazy” and “a prescription for disaster”, according to a long-time NASA climate scientist.
The paleo-climate record shows sea-levels were six to eight metres higher than current levels when global temperatures were less than two degrees warmer than they are now, Professor James Hansen, formerly head of NASA’s Goddard Institute for Space Studies and now at Columbia University in New York, said.
“It’s crazy to think that 2 degrees celsius is a safe limit,” Professor Hansen told RN Breakfast on ABC Radio on Tuesday, adding that this would lock in several metres of sea-level rise by the middle of the century,
Someday, probably not soon, alarmists like James Hansen will realize they’re undermining their arguments when they make statements like the “paleo-climate record shows sea-levels were six to eight metres higher than current levels when global temperatures were less than two degrees warmer than they are now.”
Those claims confirm a sad reality. If sea levels were higher in the past than they are now, then solar panels and wind generators will not stop the oceans from invading our coastal towns, villages and cities. Global temperatures have been above the threshold needed to melt glaciers and ice sheets since the end of the last ice age. Sea levels will not stop rising until global surface temperatures drop and we head back toward another ice age.
Figure Intro-6 from my upcoming book…hopefully available early in 2016
For additional recent quotes from James Hansen, see the full article Paris 2015: Two degrees warming a ‘prescription for disaster’ says top climate scientist James Hansen at The Age.