I repeat, once again, that I believe that the balance of the evidence suggests that man-made global warming could become a significant problem for humanity as this century unfolds. OK, that is now out of the way. So let's turn to a sleazy attempt by some climate scientists (activists?) to undercut scientific findings by other researchers that call into question their assertions about global temperature trends.
University of Alabama at Huntsville climate scientists John Christy and Roy Spencer have been reporting data from NOAA satellites that measure the temperature of the mid-troposphere since 1979. Their data show that global average temperature has been essentially flat for the past 18 years. This is very inconvenient for rival researchers whose climate models have projected that significant warming should have occurred during this period as humans continue to burn more fossil fuels and load up the atmosphere with global-warming carbon dioxide. In addition, there is a significant mismatch between the surface temperature data sets that show higher rates of warming than do the satellite data.
So what to do? What good scientists would do is try to reconcile the datasets and debate the issues in the scientific journals. Well, that's messy, slow, and the results are not pre-determined. So what a trio of climate scientists—Michael Mann, Kevin Trenberth, and Ben Santer—have evidently decided to do is participate in a video project funded by an climate activist foundation whose chief aim is to cast doubt on the satellite data.
Why now? Because various government agencies are shortly going to declare that 2015 is the warmest year ever in the historical surface temperature records. The climate scientists in the video evidently fear that "climate deniers" will dismiss these dire declarations by pointing to the satellite data which show a considerably slower rate of warming. Solution: Deny data that contradicts their preferred narrative. This is not science!
Over at Breitbart, Christy responds to the video:
There are too many problems with the video on which to comment, but here are a few.
First, the satellite problems mentioned here were dealt with 10 to 20 years ago. Second, the main product we use now for greenhouse model validation is the temperature of the Mid-Troposphere (TMT) which was not erroneously impacted by these problems.
The vertical "fall" and east-west "drift" of the spacecraft are two aspects of the same phenomenon – orbital decay.
The real confirmation bias brought up by these folks to smear us is held by them. They are the ones ignoring information to suit their world view. Do they ever say that, unlike the surface data, the satellite datasets can be checked by a completely independent system – balloons? Do they ever say that one of the main corrections for time-of-day (east-west) drift is to remove spurious WARMING after 2000? Do they ever say that the important adjustment to address the variations caused by solar-shadowing effects on the spacecraft is to remove a spurious WARMING? Do they ever say that the adjustments were within the margin of error?
In addition, another group, Remote Sensing Systems, established explicitly to independently evaluate the satellite temperature data finds the same overal temperature trend as the folks at the University of Alabama. See Christy's version of the mismatch between model projections and satellite and weather balloon temperature trends below.
If these researchers have any real arguments showing that the satellite data are wrong, the place to prove that is in the peer-reviewed scientific literature—not a propaganda video.