Climate science facts: Global warming is no fiction

Climate Change: Evidence and Causes has just been published jointly by the U.S. National Academy of Sciences and the U.K.'s Royal Society. These two organizations are esteemed for their scientific and technical excellence, having similar missions to "promote the use of science to benefit society and inform critical debates" in their respective countries.

This report, written in accessible language and not scientific jargon, presents an excellent synthesis of current science, laying out clearly what is settled science at this point about climate, and what areas can't yet be fully predicted in detail. The authors avoid politics and any discussions of what should or shouldn't be done. "Just the facts,  ma'am." The scientific facts, fortunately.

Some settled facts: Climate is warming globally, on average 1.4 degrees (F) since 1900, with much of the warming since 1970. Sea ice is decreasing. Ocean temps and sea level are rising. This is all beyond argument.

More facts: Sun spots are not responsible for overall warming. Human activity is responsible for overall warming. However, natural phenomena like El Niño can show some slight, short-term warming. But these phenomena don't influence the decades-long warming trends we're now seeing.

The report is written in Q&A format and is easily browsable, with helpful graphics. Question 5, for example, discusses the fact that temperature change patterns are different in the upper and lower atmosphere. If human activity were not influencing global climate, science tells us that the sun would warm upper and lower atmospheres equally. But we're overwhelmingly seeing warming only in the lower atmosphere -- a human fingerprint predicted by climate models. The report mentions a couple of regional anomalies in the data, but not nearly enough to topple the models.

Some other sections I found interesting:

Q9 discusses why the rates of warming vary from decade to decade and place to place, but that this finding  doesn't contrast fundamentally with the fact that the overall climate is rising.

Q12 discusses why we're observing different patterns of sea ice changes in the Arctic versus the Antarctic. Briefly, the Arctic sea ice is steadily shrinking, while Antarctic sea ice is increasing slightly, with some localized shrinking. The authors ascribe these patterns to differences in nearby land masses and how sea winds affect the two poles, among other factors -- not as a refutation of the reality of global warming.

One of the reviewers of the report is Penn State's own Prof. Richard Alley. We at PennFuture give a big shout-out to Richard for his ongoing excellent science and leadership on the issue of climate change.

I suggest you take a look at this new report. Lots of good stuff here, and well worth your time.

Joy Bergey is federal policy director for PennFuture and is based in Philadelphia.