A Startling New Climate Change Revelation!
Call out the troops, call the Marines, we need tanks, lots of tanks. Well okay, maybe not. Brute force won’t stop global warming and thanks to a new study on the subject it turns out, not much else will either. Oh there is of course the obvious lower CO2 emissions, but that’s not a big deal. I don’t know why it takes scientific studies to tell us this, but the greenhouse gas CO2 that we pump out in millions of tons — roughly 88 million tons, US of course since metric tonnes has to be different, or maybe that’s our fault — is bad for the environment.
I know we tend to think of ourselves as intelligent and generally I won’t argue otherwise, but let me just say… really?
Among the climate pollutants humans put into the atmosphere in significant quantities, the effects of carbon dioxide [CO2] are the longest-lived, with effects on climate that extend thousands of years after emissions cease. But as with most things, finding the political consensus to act on reducing CO2 emissions has been nearly impossible. So there has been a movement to make up for that inaction. This is done by reducing emissions of other, shorter-lived gases, such as methane, hydrofluorocarbons, nitrous oxide, and particulates such as soot and black carbon, all of which contribute to warming as well.
But according to a comprehensive new study by University of Chicago climatologist Raymond Pierrehumbert that effort has been, as he puts it, a delusion. “Until we do something about CO2, nothing we do about methane or these other things is going to matter much for climate,” he said. Let’s just say now, I like this guys style — in a world where we use flowery language and try to convince people that there is not a general consensus on the matter, saying it’s a delusion tantamount to calling the people in charge morons… which sad to say, they must be if they don’t want to fix this.
Pierrehumbert is the Louis Block Professor in Geophysical Sciences at UChicago. His study, brings together findings from the scientific literature with new research and analysis. Its conclusions are clear:
“Ray convincingly shows the benefit and importance of doing everything we can to lower CO2 emissions, and as soon as possible,” said Katherine H. Freeman, professor of geosciences at Pennsylvania State University. “We should lower short-lived pollutants like methane too. But, as he makes clear, we should not let them distract us from the urgent need to stop burning fossil fuels.”
It’s really not that hard to understand, the basic physics of climate pollutants has been well known for a long time. The warming effect of methane and other short-lived climate pollutants disappears quite quickly after the pollutants are removed from the atmosphere. When you remove them, you get a one-time-only, lump-sum benefit. CO2, on the other hand, lingers in the atmosphere. And if you are still emitting CO2 while you are reducing methane and other greenhouse gases, that additional CO2 continues to affect the climate for thousands of years.
Perhaps as a result of wishful thinking — the policy implications of those facts had become confused. Truthfully, part of the problem is that the statistical tool used to compare the climate effect of gasses is badly flawed. The measure, which is called Global Warming Potential [GWP], predicts the effect on climate by comparing the emission rate of carbon dioxide with the emission rate of methane. But a one-ton-per-year reduction in the amount of methane emitted only translates into a single lowering of the global thermostat, while a one-ton-per-year reduction in CO2 yields a climate benefit that increases over time. That’s because each extra ton of CO2 that would have been emitted would have irreversibly ratcheted up the global thermostat by an additional increment.
Of course, despite its well-known defects, GWP has been used since 1990 and was incorporated into the Kyoto Protocols which are just the climate-trading schemes implemented by Europe via the United Nations. However, the study proposes a different metric, which looks at the climate effect of reducing CO2 emission by a fixed number of tons and then finds the rate by which you have to reduce methane emissions to get the same effect.
The study itself doesn’t propose a single “right” policy on climate change, but it is a very useful analysis that should be viewed carefully by people who are interested in making good policies, and hopefully the main conclusions will be taken into consideration when policies are being made. Pierrehumbert himself hopes that his work will help lead policymakers to abandon Kyoto-style multi-gas trading schemes [which treat the gasses equivalently] and put the emphasis on CO2 for the next 50 years or so.
“I see puncturing the excessive enthusiasm about short-lived climate pollution control as a step in the right direction,” he said, “because it takes away one of the grounds for procrastination on CO2. If you’re serious about protecting climate, it’s the CO2 you’ve got to deal with first.”
Does this all sound redundant? Yeah, I think so too, maybe it’s time for the people who can actually implement the changes needed to start doing it. Of course, they will all be long gone before we have to pay for the mess they leave behind, so why not. Who really cares about a mess you don’t have to clean up anyway?
Not bored with all this climate talk? You probably want the full study, which you can find —here!
Pierrehumbert, R. (2014). Short-Lived Climate Pollution Annual Review of Earth and Planetary Sciences, 42 (1), 341-379 DOI: 10.1146/annurev-earth-060313-054843