In a Wall Street Journal op-ed, Matt Ridley attempted to cast doubt on the severity of manmade climate change, arguing that future warming will be modest and “good” for the planet. But experts say the author flubbed the science, and continue to project that the earth will warm between 2 and 4.5 degrees Celsius (or about 3.5 to 8 degrees Fahrenheit), unless mitigating action is taken.
Ridley's argument goes something like this: climate models are “unproven.” Therefore, it is now possible to rely solely on “observations” -- which show that temperatures are “no higher than they were 16 years ago” --to determine that a doubling of atmospheric carbon dioxide by the end of the century would cause modest warming, a development he says is “dynamite.” Further, that amount of warming would be a “net good.”
Putting aside the fact that Ridley cites a “semiretired successful financier” and an unnamed scientist to support his claims, his arguments are not well-founded. Or, as John Abraham, an IPCC reviewer and the director of the Climate Science Rapid Response Team, put it to Media Matters: the column “has such elementary errors in it that [it] casts doubt on the author's understanding of any aspects of climate change.”
Let's look at each of those errors, one by one.
First, Ridley wrongly argues that three variables factored into current climate models are overstated (and thus that climate models are “unproven” ). In fact, experts agree that the basic impacts of each variable that Ridley cites -- the cooling effect of aerosols (or particles in the air); the rate of heat absorption by the world's oceans; and the role of water vapor in amplifying climate change -- are unambiguous.
With regard to aerosols: Abraham told Media Matters: “it is very clear [they] have a cooling impact,” adding, “I don't know of any reputable scientist that would dispute that.” Boston University's Robert Kaufmann, lead author of a 2011 sulfur emissions study, agreed:
I know of no evidence that would suggest that the temperature effect of sulfur emissions are small. This conclusion is totally at odds with my peer reviewed publication in the area, which indicate that sulfur emissions have a significant effect on temperature.
With regard to the feedback effect of water vapor: Kevin Trenberth, a scientist with the National Center for Atmospheric Research, told Media Matters in an email: “water vapor effects are well established as an amplifier (strong positive feedback).” Abraham further noted that Ridley has apparently confused water vapor with clouds, whose effects are not as well understood. He said, “it is very clear water vapor...is an amplifying effect. It is a very strong warmer for the climate” and challenged Ridley to name the anonymous scientist who gave him his information.
With regard to the rate of ocean heat absorption: Trenberth wrote: “On the contrary there is now very good evidence that a LOT of heat is going into the deep ocean in unprecedented ways, which completely undermines this sort of argument. OHC [Ocean Heat Content] keeps increasing at a fairly steady rate, just as sea level keeps going up.” Abraham, who has done extensive research on ocean heating, agreed, saying: “oceans are absorbing a tremendous amount of energy...whoever said [the ocean's heat absorption rate is down] has no basis in fact...he's making [stuff] up.”
As this chart from Skeptical Science shows, the rate of ocean heat absorption remains high:
Ridley goes on to cite inadequate variables to claim that temperatures have not risen in 16 years. While surface warming over that period has indeed been slight, surface temperatures make up only a fraction of global warming - the effect of which has been felt most significantly in the world's oceans since about 1960. As a 2011 graphic illustrates, the oceans have heat capacity far greater than the atmosphere, and thus absorb a massive percentage of global warming:
Finally, Ridley is just plain wrong to claim that future warming will be mild or even helpful. When contacted by Media Matters, scientists were blunt. Trenberth wrote “There is now widespread agreement that stopping global mean [temperature] increase at 2 [degrees] C [3.6°F] is impossible. Rather 3 [degrees] C [5.4°F] will be difficult.” Andrew Dessler, a climate scientist at Texas A&M, conceded that estimates of climate sensitivity for doubled carbon cover a range of outcomes, but wrote in an email that “the IPCC's canonical range gives about the right probability distribution: 2-4.5°C [3.6-8.1°F] is the likely range, with values below 1.5°C [2.7°F] being very unlikely.”