Armchair critics of climate-change science are fond of pointing out the rate of global mean temperatures has stabilized since the start of the millennium. But, as usual, their arguments are superficial and lack understanding of the issue’s complexities.
The Aug. 22 issue of Science has a number of relevant articles. The most revealing article is entitled, “Varying planetary heat sink led to global-warming slowdown and acceleration.”
It was written by scientists from the Key Laboratory of Physical Oceanography and the Department of Applied Mathematics at the University of Washington — people who know how to collect and analyze data.
Their data came from extensive measurement around the globe. Importantly, it included data from ocean depths to as much as 1,500 meters (about one mile). In general, they found increases in heat absorption in the layer between 300 and 1,500 meters. This tended to moderate warming in the top 300 meters.
This means surface temperature increases were being moderated because heat was being sequestered at greater depths. Surface temperatures strongly influence atmospheric temperatures.
Their analysis demonstrates much of the supposed “missing heat” has actually been stored in the depths of the Atlantic and southern oceans. It further seems to demonstrate the extensive “conveyor belt” mechanism at play in these oceans has been the key mechanism in this deep sequestration.
Other oceanographers and atmospheric scientists think ocean dynamics in the Pacific are at least as significant in deep ocean heat sequestration. In each of these scenarios the oceanic patterns oscillate over about a 20-to-30 year time frame.
The final conclusion of the main article states, “When the internal variability that is responsible for the current hiatus switches sign, as it inevitably will, another episode of accelerated global warming should ensue”.
In other words, the oceanic patterns are cyclical and when they return to the unfavorable phase of that cycle we will see accelerated warming. The longer-term trend, averaged over many cycles, is for unremitting increases in temperature.
The effects of deeper layers of the oceans periodically absorbing heat isn’t sustainable and may itself upset oceanic currents that moderate temperatures around the globe.
Scientists acknowledge the need for more data and improvements in their analytic methods. But, it is disingenuous of critics to ask for data, and then ignore what they are shown. They have no data themselves and their armchair methods aren’t likely to produce any.