Thursday, August 14, 2014

What if the Problem is Not Global Warming, but Continued High Temperatures?

    We were discussing global warming at the Indiana Law and Economics Lunch, and the curious path of world temperatures.  From NASA data, which is standard, the pattern is that temperatures rose from 1980 to 2000 and then stopped increasing (but stayed high). This doesn’t necessarily mean we can forget global warming as a problem, though--- something I hadn’t thought about before--- because maybe the continued high temperatures will cause big problems even if temperatures don’t rise any more.  It could be, for example, that Greenland’s ice will melt and raise the sea level. Whether that would happen or not, if the temperature stays constant, I don’t know.







But this implies current suggestions for global warming policy are totally misguided.

      If temperature has stalled, but we still have  a big problem because of continued high temperatures, then carbon taxes, cap-and-trade, etc.  won't help in the slightest. Restricting carbon output is only good for keeping the temperature from rising, and if it's not rising any more, that’s addressing the wrong problem. Rather,  we'd need to actually REDUCE the amount of carbon in the atmosphere (if carbon was  indeed the cause of the 1990's warming, and it has stopped only because of negative feedback via clouds, etc.), which absolutely nobody proposes. Rather,  if we need to actually reduce the temperature rather than stop it from increasing, the only solution would be climate manipulation via putting some kind of particulate in the atmosphere. 

The Supreme Court decided in EPA vs. Massachusetts in 2007 that  carbon dioxide was a pollutant and needed regulating, regardless (if I remember rightly) of whether the regulation would make any detectable difference to the global temperature (or the Massachusetts seashore, the plaintiff's alleged source of injury).  Suppose the global temperature continues to stall for 30 years, or even decline. Would that affect the Supreme Court decision? Or would it be like  with Brown v. Board of Education, where the experiments with black and white dolls and self esteem wasn't really the key to the holding?

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It is true that temperatures will remain high even if emissions are reduced. Carbon dioxide is a stock "pollutant" (just bear with me), and there is a certain amount of temperature increase already "baked in." Calculating the social cost of carbon is a complicated thing, but roughly speaking the rationale for pricing carbon is that we have to at least start reducing the flow, and eventually find ways to reduce the stock. There are natural carbon sequestration processes, and if emissions are reduced sufficiently, then the flow could turn negative and the stock reduced.

Posted by: Shi-Ling Hsu | Aug 14, 2014 7:27:40 PM

Lawyers and economists discussing climate science. One shudders at the thought. Eric, I believe there was an episode of Cosmos that gives a decent primer on the subject and may answer some of your questions. Long story short: the CO2 that we have already pumped into the atmosphere (which is far more significant than the earth puts into the atmosphere via volcanic activity and similar) isn't going anywhere, will continue to trap more of the sun's energy (i.e. heat) in the atmosphere, where it will be primarily absorbed by the oceans, aiding in their warming and the consequent melting of the polar ice. I believe there was also a discursion into how the melting of the far permafrost, up along the north coast of Alaska and Canada, is releasing enormous amounts of trapped methane, which is considerably more effective at trapping heat than CO2.

Posted by: Unemployed Northeastern | Aug 18, 2014 7:08:39 AM

My point, though, was that the temperature is *not* increasing. Contrary to the carbon dioxide theory, carbon dioxide is high and increasing, but no more heat is being trapped--- the temperature is staying the same. That higher temperature might cause problems, but it seems that increasing carbon dioxide has not caused harm and reducing it will not reduce harm.

Posted by: Eric Rasmusen | Aug 21, 2014 6:26:43 AM

From our good friends at NOAA last November: "Why did Earth’s surface temperature stop rising in the past decade?"

The first paragraph explains it nicely: "The most likely explanation for the lack of significant warming at the Earth’s surface in the past decade or so is that natural climate cycles—a series of La Niña events and a negative phase of the lesser-known Pacific Decadal Oscillation—caused shifts in ocean circulation patterns that moved some excess heat into the deep ocean. Even so, recent years have been some of the warmest on record, and scientists expect temperatures will swing back up soon."

See also: "The long-term trend—change over the course of a century or more—is what defines “global warming,” not the change from year to year or even decade to decade."

So, due to short-term changes in global ocean & wind patterns, the deeper layers of the Pacific Ocean are absorbing more of the heat trapped in our atmosphere by excessive CO2 levels. Beyond the well-known consequences that warmer oceans will cause with regards to ice caps and the weakening of the jet stream and so on, the rearranging of various thermoclines, haloclines, and chemoclines can (and almost certainly will) wreak havoc on the ocean's natural levels of temperature, nutrient levels, salinity concentration, etc, which will radically alter the composition, numeracy, and distribution of our worldwide fishing stocks and ecosystems, most of which are already in fairly profound danger.

Posted by: Unemployed Northeastern | Aug 22, 2014 12:20:32 PM

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