It has been quite entertaining to watch the various explanations coming out to rationalize “the pause” in surface temperatures for the last 16 years. For example, as Jerome Ravetz points out to me in email, The Times Hannah Devlin says the warming has just gone into hiding.
But there is a funny thing about that deep ocean warming.
As Bob Tisdale wrote:
Ever since the NODC released their ocean heat content data for the depths of 0-2000 meters and published Levitus et al (2012), it seems that each time a skeptic writes a blog post or answers a question in an interview, in which he or she states that global surface temperatures haven’t warmed in “X” years, a global warming enthusiast will counter with something to the effect of: global warming hasn’t slowed because ocean heat content continues to show warming at depths of 0-2000 meters. Recently, those same people are linking Balmaseda et al (2013) and claiming the warming of ocean heat content data continues.
It is true that the NODC’s ARGO-era ocean heat content (0-2000 meters) continues to warm globally, but always recall that the ARGO data had to be adjusted, modified, tweaked, corrected, whatever, in order to create that warming. That is, the “raw” ocean heat content data for 0-2000 meters shows the decreased rate of warming after the ARGO floats were deployed. (See the post here.) Also, while the much-revised NODC ocean heat content data for 0-2000 meters might show warming globally, it shows very little warming for the Northern Hemisphere oceans since 2005. See Figure 1.
Can well-mixed human-created greenhouse gases pick and choose between the hemispheres, warming one but not the other? One might think that’s very unlikely.
Something else to consider: the Northern Hemisphere warming of ocean heat content for depths of 0-2000 meters occurs in only one ocean basin, and it’s not one of the big ones.
Right there is a premise falsifier. But I find this figure even more interesting:
There was a comparatively minor warming in the Northern Hemisphere at depths of 0-2000 meters from 2005 to 2012. But the upper 700 meters in the Northern Hemisphere cooled. The difference is provided to show the additional warming that occurred at depths of 700 to 2000 meters.
So the question here is simple. As Hannah Devlin writes in the Times:
The pause in global warming during the past decade is because more heat than expected is being absorbed by the deep oceans, according to scientists.
How does that heat get to the deep ocean hidey hole, down to 2000 meters, without first warming the upper 700 meters in transit? That’s some neat trick.
You can read more on how that deep ocean hidey hole doesn’t seem to hold up when the data is examined carefully here.
The claim has been made that its the sun doing it:
[Tisdale] SkepticalScience’s Rob Painting provides a reasonable explanation of the hypothetical cause of greenhouse gas-driven warming of the global oceans in the post Observed Warming in Ocean and Atmosphere is Incompatible with Natural Variation. Painting writes (my boldface):
Arguably the most significant climate-related impact of increased concentrations of greenhouse gases in the atmosphere, is that they trap more heat in the ocean. Over the last half-century around 93% of global warming has actually gone into heating the ocean. A little-known fact is that the oceans are almost exclusively heated by sunlight (shortwave radiation) entering the surface layers.
Back in 2009 it was claimed that solar radiation changes would do just that:
Well Duncan, we are still here, speaking clearly to the issue.
That article was a reaction to this Judith Lean Paper in GRL (bold mine):
How will Earth’s surface temperature change in future decades?
Judith L. Lean, David H. Rind Article first published online: 15 AUG 2009 DOI: 10.1029/2009GL038932
Reliable forecasts of climate change in the immediate future are difficult, especially on regional scales, where natural climate variations may amplify or mitigate anthropogenic warming in ways that numerical models capture poorly. By decomposing recent observed surface temperatures into components associated with ENSO, volcanic and solar activity, and anthropogenic influences, we anticipate global and regional changes in the next two decades. From 2009 to 2014, projected rises in anthropogenic influences and solar irradiance will increase global surface temperature 0.15 ± 0.03°C, at a rate 50% greater than predicted by IPCC. But as a result of declining solar activity in the subsequent five years, average temperature in 2019 is only 0.03 ± 0.01°C warmer than in 2014. This lack of overall warming is analogous to the period from 2002 to 2008 when decreasing solar irradiance also countered much of the anthropogenic warming. We further illustrate how a major volcanic eruption and a super ENSO would modify our global and regional temperature projections.
Since that obviously hasn’t happened, and “the pause” is an inconvenient truth, the cheerleaders are looking for alternate explanations. Voila! The deep ocean hidey hole.
The ocean provides the perfect cover for global warming because unlike the atmosphere, few people experience it directly. Few people go diving down to 2000 meters with thermometers and few people go swimming in the ocean with pH meters to check the claims of “ocean acidification”.
On the other hand, virtually the whole of humanity can and has experienced “the pause” in air temperatures.
When the deep ocean hidey hole doesn’t pan out in a few years, and that stored hidden warming doesn’t spring out of the deep ocean like a caged lion, where will they put the warming next? They are running out of places.