Today I read a new study by Australian scientists has found the Southern Ocean is acidifying faster than previously thought. Their research leads them to believe an acidification tipping point could be reached by 2030 ~450 ppm instead of the earlier estimate of 2060 ~550 ppm. We have had a deluge of similarly startling findings these past few years such as the acceleration of melting in the Arctic Ocean, Greenland, and western Antarctica. Many climate scientists at Princeton and other academic institutions have seemed comfortable limiting carbon dioxide equivalent concentrations to a doubling at ~550 parts per million in the atmosphere (ppm). This was the basis for Socolow and Pacala’s groundbreaking article on wedges a few short years ago. But the environmental community and a number of scientists are beginning to set their targets on lower levels.
Leading voices include James Hansen and Bill McKibben who call on concentrations not only to stop rising, but also to fall from today’s ~385 ppm down to 350 ppm. They make the case that we have already reached a concentration that would, if left this high, set off catastrophic climate change and a sea level rise of many meters. Their belief stems from a review of the history of Earth’s climate over the last many million years that shows whenever GHG concentrations were this high, sea level was more than 75 feet above the level today. Those who push for a global regime to achieve 450 ppm (or higher) believe the transition to less ice and higher seas will occur so slowly that we can adapt more easily over the next century than we can revolutionize our energy system from fossil fuels to zero carbon sources over the next 25 years.
For instance, the US has hundreds of billions invested in coal plants, sunk costs that lead rational economists to think Al Gore’s Repower America plan (zero carbon electricity in 10 years) is a nonstarter. But if Hansen and McKibben are right about the catastrophic costs of >350 ppm, maybe Al Gore has chosen the best target. And when our country sets its mind to something, impossibilities disappear. Maybe Obama can help inspire a sustainable energy transition over the next eight years on the scale of the ’40s war effort or the ’60s Apollo Project.
My current thinking focuses on the 450 ppm goal as a policy driver for now (which would take tremendous change in the developed world of an 80% cut in emissions over the next 42 years). As yesterday’s blog described, our country can probably achieve this at very little cost. As long as we set up our cap and trade system as a flexible instrument ready to adapt, we will be set. If the scientific consensus emerges that 450 ppm is indeed too high, the emission cap cuts should accelerate accordingly. My energy portfolio projections make zero carbon US electricity more plausible for 2030+ (even with aggressive growth for wind, solar, and efficiency) than Gore’s call by 2018. But I think institutions with ample resources should be Repower America models. For instance, Princeton University should step up and join Google, Yahoo!, UNC-Chapel Hill and others committed to climate neutrality in their global footprint. Once the models are established (with their lessons learned through success and failure), they can guide the nation and indeed the world to a sustainable future.
What do you think is the optimal GHG concentration?
Should we aim for 350, 450 or some other level? What first steps do you think the new federal government should take?
Together, we can stabilize the climate and achieve energy security.
Tags: Al Gore, Barack Obama, cap and trade, climate change