Proceedings of the National Academy of Sciences (PNAS) has published a study by 13 scientists that provides “clear evidence for a discernible human influence on the thermal structure of the atmosphere.”
The study, led by Benjamin Santer of the Lawrence Livermore National Laboratory, reports that, over the 34-year satellite temperature record, the troposphere (middle atmosphere) has warmed while the lower stratosphere (the atmospheric layer above the troposphere) has cooled. This is the vertical pattern or “fingerprint” predicted by greenhouse theory.*
Climate models run with only known internal climate variability (such as the El Niño/Southern Oscillation ocean cycle) and natural “forcings” (such as changes in solar irradiance and volcanic aerosol emissions ) do not produce this pattern. Models produce the “fingerprint” only when they are also “forced” with anthropogenic greenhouse gas emissions.
In layman terms, human-caused global warming is real. OMG!
Why, you might wonder, is cooling of the lower stratosphere evidence of man-made global warming? Greenhouse gases warm the planet by blocking outgoing infrared radiation that would otherwise escape to outer space. As greenhouse gas concentrations increase in the troposphere, less outgoing heat energy reaches the lower stratosphere.
Is this a momentous discovery? No, it’s a yawn.
Back in the early 2000s, prominent climate “skeptic” Patrick Michaels explained to me that surface and tropospheric warming combined with stratospheric cooling were strong evidence of anthropogenic climate change. He said: “The Sun doesn’t only shine in Irkutsk” (i.e. in the high northern latitudes where most of the Earth’s surface warming has occurred).
His point? The Sun also shines on the stratosphere. If changes in solar irradiance were the primary cause of global warming, the stratosphere should be warming too. Instead, it’s cooling.
After savoring Pat’s Irkutsk quip for a few moments, I accepted the implication and moved on. Apparently, the Santer team and PNAS still consider it big news.
The PNAS paper is, I suspect, a desperate attempt to divert public attention from the crisis in “consensus” science due to the modeling fraternity’s failure to anticipate a 16-year pause in global warming. Publishing another study ‘proving’ the reality of climate change amounts to ignoring the elephant in the room.
Try as they might to change the subject, however, the elephant is conspicuous in their “clear evidence” that climate change is real.
Here is the vertical profile (“fingerprint”) of changes in atmospheric heat projected by the latest climate models:
Here is the observed pattern based on the Remote Sensing Systems (RSS) dataset:
Note what’s different: The tropical troposphere warms much faster in the models than in the observations. [click to continue…]