More on Global Warming

Last week I posted a Q & R about global warming. My friend Paul H sent in this reply, which is full of helpful information. Here’s Paul’s reply:

Brian, I just read your excellent response to the guy who so desperately (and I wonder why) wants to believe that there is no global warming. One of his points was that, if there is global warming, we cannot account for the temperature plateau of the past 15 years or so. He’s wrong about that. Apparently, he has never looked at the actual temperature time series, one version of which is in the Global Surface Temperature plot on this NASA webpage:
Even a cursory examination of the time series shows that the warming of the globe is not monotonic (continuously rising), but the overall trend is undeniable. The climate research community recognizes a phenomenon known as “decadal variation” — variation on the scale of one or a few decades, and they spend considerable effort trying to understand it. The atmospheric circulation system has a number of recognized oscillatory systems, such as the El Niño Southern Oscillation, the North Atlantic Oscillation, the Madden Julian Oscillation, and others. It’s pretty certain that there are other factors that are not yet recognized. Taken all together, these factors cause the globally averaged temperature (and many other parameters) to have ups and downs that are superimposed upon the long-term trend.
We see decadal variation clearly on the webpage cited above. The first half of the 1950s and the first half of the 1970s are plateaus very similar to the current one. Other decadal variations show actual drops in globally averaged temperature. These are in no way contradictory to the conclusion that global warming is real. The long-term trend is still an increase of globally averaged surface temperature.
Some of the media-fueled skepticism about this comes, oddly, from meteorologists, particularly those who work in the broadcast news industry. This is in no small part due to the influence of John Coleman, one of the founders of the Weather Channel. He is an outspoken climate change denier, but one who has exactly zero credibility. He is not a climate scientist. He is not even a meteorologist. His education is in journalism. The fact that he employs meteorologists does not give him any credibility.
A couple of years go, Prof. Richard Muller, a respected physicist and climate change skeptic, assembled a research team and acquired copies of all or most of the same data that has led the climate research community to the conclusion that global warming is real and anthropogenic. He completely reanalyzed the entire, very large collection of data. Even though his research was funded in part by the Koch brothers, his widely published conclusion was that climate change is real, it involves an increase of globally averaged temperature, and it is caused by the activities of mankind, principally the release of carbon dioxide into the atmosphere.
Every year, I attend the Annual Meeting of the American Meteorological Society, and I tend to focus on the climate change sessions. In 2007, one aged member of the society rose in a plenary session, to say (in the quavering voice of an old man) that he simply could not accept the idea that a system as massive as the atmosphere could possibly be affected by the actions of puny humans. That old man and a couple of broadcast meteorologists (overheard in a conversation at lunch) are the only examples I know of any Society members disbelieving global warming. It may be that 97% of scientists believe it. I don’t know where you got that number. But I strongly suspect that a much stronger proportion of climate scientists (meaning those who actually study climate and, thus, have credibility) believe it.
As is the case with nearly everything in life, basing an opinion on anything other than actual data is perilous.

I just heard the 97% number recently at a briefing I was part of, but it may be already out of date, as I think the consensus only grows stronger. It referred to all scientists, not just climate scientists. I imagine, as Paul says, that it would be much higher among those who study the data most closely.