Wednesday, February 10, 2016

Reality Check - Man Made Climate Change Will Last for Thousands of Years

We have left our mark on the Earth and our environmental footprint is going to last probably 10-thousand years or more.

We typically think in terms of a decade, perhaps a century, when considering anthropogenic global warming and its impacts but that's just us doing what we do best - thinking in terms of "us." We're a very us-centric bunch. That limits the scope to us, the kids, the grandkids and maybe just a smidgen of concern for great-grandkids too. After that, not so much.

From The Washington Post:

A large group of climate scientists has made a bracing statement in the journal Nature Climate Change, arguing that we are mistaken if we think global warming is only a matter of the next 100 years or so — in fact, they say, we are locking in changes that will play out over as many as 10,000 years.

“The next few decades offer a brief window of opportunity to minimize large-scale and potentially catastrophic climate change that will extend longer than the entire history of human civilization thus far,” write the 22 climate researchers, led by Peter Clark, from Oregon State University.

“In hundreds of years from now, people will look back and say, ‘Yeah, the sea level is rising; it will continue to rise; we live with a constant rise of sea level because of these people 200 years ago that used coal, and oil and gas,’ ” said Anders Levermann, a sea-level-rise expert at the Potsdam Institute for Climate Impact Research and one of the paper’s authors. “If you just look at this, it’s stunning that we can make such a long-lasting impact that has the same magnitude as the ice ages.”

The key reason for this is that carbon dioxide stays in the atmosphere for a very long time before being slowly removed again by natural processes. “A considerable fraction of the carbon emitted to date and in the next 100 years will remain in the atmosphere for tens to hundreds of thousands of years,” the study noted. Meanwhile, the planet’s sea levels adjust gradually to its rising temperature over thousands of years.

...From 1750 to the present, human activities put about 580 billion metric tons, or gigatons, of carbon into the atmosphere — which converts into more than 2,000 gigatons of carbon dioxide (which has a larger molecular weight).

We’re currently emitting about 10 gigatons of carbon per year — a number that is still expected to rise further in the future. The study therefore considers whether we will emit somewhere around another 700 gigatons in this century (which, with 70 years at 10 gigatons per year, could happen easily), reaching a total cumulative emissions of 1,280 gigatons — or whether we will go much further than that, reaching total cumulative levels as high as 5,120 gigatons.

The good news is that the authors believe that, at some point, mankind's predicament will become sufficiently perilous that we will develop some technology for stripping atmospheric carbon dioxide - if, by then,  we can afford what will probably be a massive cost. The better news is that, if we do get to that point, the people with the greatest wealth will be those on the hook to clean up the very mess that they in fact made.


Northern PoV said...

Interesting piece very much in line with the part of Lovelock's Gaia theory that examines the rapid 'shift' periods (to colder or warmer), then long static stable periods at the new temperature.

The Mound of Sound said...

Yes, I'm quite familiar with Lovelock and the Gaia hypothesis, NPoV. It would take perhaps the greatest technological achievement in mankind's history, perhaps greater than all the breakthroughs combined, to somehow restore the Holocene epoch which may be our only hope of averting another mass extinction. It's a huge challenge that confronts us, collectively, as a species and a global civilization and we have little chance of meeting it unless we approach it collaboratively.

Northern PoV said...

" greatest technological achievement"

Kim Stanley Robinson has written some Cli-Fi (Climate Sci-Fi) where we a do this....
- Building a pipeline to the top of Antarctica to pump the excess water up there where it will (presumably) again freeze.
- dumping loads of salt in the N. Atlantic to restart a broken Gulf Stream.

imo, technological attempts to fix could be disastrous .. I'd risk a biological (plant carbon capture) fix over a tech fix (but maybe I'm just splitting hairs)