by Judith Curry
Ocean heat sequestration: false sense of security, or a solution to the global (surface) warming problem?
Two alarming blog posts in the last few days on the relentless increase of ocean heat:
- What ocean heating reveals about global warming – Stefan Rahmstorf at RealClimate
- Faux pause: ocean warming, sea level rise, and polar ice melt speed up, surface warming to follow – Joe Romm at ThinkProgress
From Romm’s post:
Let me extract the key points and figures. Back in July, scientist Dana Nuccitelli summarized a new study, “Distinctive climate signals in reanalysis of global ocean heat content“:
- Completely contrary to the popular contrarian myth, global warming has accelerated, with more overall global warming in the past 15 years than the prior 15 years. This is because about 90% of overall global warming goes into heating the oceans, and the oceans have been warming dramatically.
- As suspected, much of the ‘missing heat’ Kevin Trenberth previously talked about has been found in the deep oceans. Consistent with the results of Nuccitelli et al. (2012), this study finds that 30% of the ocean warming over the past decade has occurred in the deeper oceans below 700 meters, which they note is unprecedented over at least the past half century.
- Some recent studies have concluded based on the slowed global surface warming over the past decade that the sensitivity of the climate to the increased greenhouse effect is somewhat lower than the IPCC best estimate. Those studies are fundamentally flawed because they do not account for the warming of the deep oceans.
- The slowed surface air warming over the past decade has lulled many people into a false and unwarranted sense of security.
Well, I haven’t worried very much about this sequestered heat. Without having done the arithmetic, I figured that the actual temperature increase when averaged over the global ocean is probably pretty small. Further, with the 2nd law of thermodynamics, it is not easy to get much of that heat back to surface.
Well, Lubos Motl has done the arithmetic in this post Ocean heat content: relentless but negligible. This is a good post, check it out. The punchline of his calculations: the heating in the layer 0-2000 m translates to 0.065 C +/- 20%. His calculations are essentially confirmed from this ARGO page where they confirm that since the 1960s, the warming of that layer was 0.06 °C.
So, can anyone figure out why 0.06C is a big deal for the climate? Or how all that heat that is apparently well mixed in the ocean could somehow get into the atmosphere and influence weather/temperatures/rainfall on the land? Or is sequestering heat in the ocean a fortuitous ‘solution’ to the global (surface) warming problem?