A friend of the Cornwall Alliance wrote us recently, saying:

I’ve just read Roy Spencer’s Global Warming Skepticism Busy People, and I am a little surprised at how much he concedes to the alarmists, e.g., there is warming, it is partially anthropogenic, a majority of scientists do believe in anthropogenic warming, a rise of 5 degrees Centigrade would be a problem, etc.

Are these all positions with which Cornwall Alliance agrees?  Roy describes himself early in the book as a “lukewarmer.”  Is Cornwall Alliance also a “lukewarmer”?  I guess I have not been a “lukewarmer.”  I’ve heard, and believed, that:  there has been no warming for 20 years, virtually none of any warming that has occurred is anthropogenic, a majority of scientists do NOT believe in anthropogenic warming, and any possible level of warming is not likely to be harmful and might even be beneficial.  So what does that make me, if I’m not a “lukewarmer”?  Have I been wrong about all of this all these years?

Thank you.  I so appreciate The Cornwall Alliance and all you are doing for reasoned discussion, the earth, and the Kingdom.

It’s always a pleasure to get well-reasoned questions like this, and this one offers a great opportunity to clarify our position.

Dr. Spencer’s position and Cornwall’s are quite consistent with each other, and, with allowance for slight changes in quantitative details over the years, this has been Cornwall’s position all along: that recent warming is largely natural though human activity probably contributes something to it; that human contribution, though almost certainly real, is probably much less than estimated by the IPCC and other alarmist organizations and individuals; that neither the current nor the reasonably predictable warming from human activity (or for that matter from natural causes) is or is likely to become catastrophic; and that attempting to mitigate the warming by curtailing the use of fossil fuels will almost certainly do far more harm than good, especially to the world’s poor.

Part of what might have surprised our friend is Dr. Spencer’s calling himself a “lukewarmer.” I personally haven’t applied that label to myself, largely because my own estimate of the likely warming effect of added atmospheric CO2 (perhaps 0.5C per doubling at equilibrium) is significantly lower than that of others who do call themselves lukewarmers (like Judith Curry and Pat Michaels, both of whom are friends, and who tend to estimate around 1–1.8C for doubling at equilibrium). But both my estimate and theirs are well below the prevailing views of the IPCC and definitely below the range of anything catastrophic.

I consider most of what our friend wrote describing his view to be consistent with all this.

There has in fact been no statistically significant linear warming trend over roughly the last 20 years (though global average temperature has risen and fallen, mostly by too little to reach outside the margin of error of our measurements, during that period).

Since

• roughly 0.8C of warming after 1850 occurred before 1960, and
• 1960 is about the earliest at which the IPCC is willing to say that anthropogenic CO2 (and other anthropogenic greenhouse gases) became the dominant factor in warming, and
• total warming since 1850 is only about 1.0–1.2C (with ups and downs along the way), and
• natural factors can’t be ruled out for the roughly 0.2–0.4C of warming since 1960 (with ups and downs along the way),

I conclude that anthropogenic GHGs likely can’t account for more than 0.4C and likely less than 0.2C of the total warming since 1850—which is broadly consistent with “virtually none of any warming that has occurred is anthropogenic,” though I think virtually is probably slightly too strong a word.

I don’t think, though, that it’s the case that the majority of scientists don’t believe in anthropogenic warming. I’m pretty confident that the majority do. What I’m also pretty confident of, though, is that the majority don’t believe in catastrophic anthropogenic warming, or AGW of high enough magnitude to justify spending trillions of dollars to mitigate it that might be more beneficially spent addressing other concerns (like pure drinking water, sewage sanitation, nutrition, infectious disease control, health care, electrification of homes and offices and factories, etc.) the risks from which are far greater than those from AGW.

I do think that likely AGW is probably more beneficial than harmful—in terms of both the temperature increase itself (lengthening growing seasons and expanding growing regions toward the poles) and the fertilizing effect of added CO2 on plant growth (and hence crop yields).

Although “lukewarmer” serves the important purpose of signalling that one doesn’t deny AGW, I have a sense some CAGW (catastrophic anthropogenic global warming) skeptics adopt the term partly just to gain a hearing in the first place. All too many people simply shut you down if you don’t at least make a nod toward the (mythical) “consensus” CAGW view (as opposed to the real consensus AGW view). We’ve adopted that tactic since we began (though not specifically by embracing the word “lukewarmer”), e.g., when we introduced our paper A Call to Truth, Prudence, and Protection of the Poor in a press release in 2006. Earlier this year we expressed it in an article published on the MasterResource.org blog and then republished on our website. Our Call to Truth … 2014 also presents this view.

A rose by any other name ….

 

Featured image by Terri Bateman, public domain.