Monday, July 24, 2017

Faulty Math on Climate Change, Yikes.

The battle with climate change comes down to numbers. Countries joining the fight usually pledge to reduce their greenhouse gas emissions  by some percentage of what they were at some past year by some future year. 25% from 2010 levels by 2030, that sort of thing. 2010 less 25% by 2030. Math.

These formulae aimed at achieving some warming/heating target. That was usually expressed as holding warming to 1.5 or 2 degrees Celsius above "pre-industrial" levels, i.e. the advent of the fossil energy era. Many people think that's the target to "fix" global warming. It's not. It's the target to avoid triggering natural feedback loops such as massive methane emissions that trigger runaway, i.e. extinction-grade global warming.

Who can forget when our freshly-minted prime minister, J. Trudeau, and his elegant environment minister, Dame Cathy, were the belles of the ball at the 2015 Paris Climate Summit, leading the charge to reset the warming target from 2 C to 1.5 C? Heady times. Short lived.

The problem with numbers is human nature. We tend to screw them up, we get things wrong. Somebody comes around to run the sums again and - whoop - there it is. Now we're hearing that our working numbers at Paris might have been off - brace yourselves - by a staggering 40%.

In the Paris climate treaty, nearly every world country agreed to try and limit global warming to no more than 2°C above pre-industrial temperatures, and preferably closer to 1.5°C. But a new study published in Nature Climate Changenotes that the agreement didn’t define when “pre-industrial” begins.

Our instrumental measurements of the Earth’s average surface temperature begin in the late-1800s, but the Industrial Revolution began in the mid-1700s. There’s also a theory that human agriculture has been influencing the global climate for thousands of years, but the mass burning of fossil fuels kicked the human influence into high gear.

According to the last IPCC report, to have a 50% chance of staying below the 2°C target, when accounting for non-carbon greenhouse gases, we have a remaining budget of about 300bn tons of carbon dioxide. But that was for 2°C warming above late-1800 temperatures. If we add another 0.1°C of pre-industrial warming, the study authors estimated that the budget shrinks by 60bn tons (20%), and if there was an additional 0.2°C pre-industrial warming, the 2°C carbon budget shrinks by 40%. As one of the study authors Michael Mann put it:

"Either the Paris targets have to be revised, or alternatively, we decide that the existing targets really were meant to describe only the warming since the late 19th century."

It’s an important point if we want to measure whether we’ve succeeded or failed in meeting the Paris climate targets. And it’s important to know if our budget should be set at no more than 300bn tons, or more like 200bn tons of carbon dioxide pollution.

This might sound like it's a matter of mathematical semantics and it sure sounds that way to me. Who cares if we failed to include the farts of the first oxen yoked to a plough? What matters is when mankind pulls the trigger on runaway global warming, when we trigger nature to join our greenhouse gas bacchanal. There's a lot of science suggesting we've already awoken that sleeping giant and that the dreaded natural feedback loops, or several of them, are already in action. The loss of the Arctic sea ice, that's one. The accelerating release of frozen methane deposits in the tundra and the Arctic sea bed, that's another. There are plenty more.

On the other hand, if our working numbers are off 40% that's something we can't overlook. We need to know and, if these claims are right and there is a real problem, we need to fix that hole in the dike. If we did get it so wrong at the Paris climate summit, what else might we have missed?


Lorne said...

My sense is that we have already passed the point of no return,Mound, in that feedback loops are surely already at work. While the current popular coverage seems to fixate on rising water levels and intense rainfall those are only two aspects of a much larger and very troubling scenario of what awaits us around the corner.

The Mound of Sound said...

A good many Americans now getting worked up over sea level rise still reject the concept of anthropogenic global warming and insist that sea level rise is an isolated, independent phenomenon. They're trying to hedge their bets.

Toby said...

Humanity has always found security in islands, sometimes physical, sometimes tribal, usually arbitrary. We are trending toward islands which are in one way or another are the least hurt by global warming. I think that gated communities are very much part of our future. The gated communities of the wealthy and powerful will be domed or in silos that are climate controlled, self sufficient and well armed to keep out intruders such as you and me. I see no evidence that the well heeled intend to seriously tackle climate change or provide for the common weal. Yes, it will all be more or less dysfunctional and will remain so until the world population has shrunk dramatically.