The McPherson Paradox, Very Briefly

This essay provides a five-paragraph overview of the McPherson Paradox. The paradox is described even more briefly in this opening paragraph. Industrial civilization is a heat engine driving humans and many other organisms to extinction. Stopping or slowing industrial civilization heats the planet even faster than maintaining industrial civilization does, thereby accelerating the ongoing Mass Extinction Event. Slightly more comprehensive versions of the McPherson Paradox can be found here and here, and video versions are available here, here, and here.

First, though, a reminder: Human extinction might have been triggered several years ago when the global-average temperature of Earth exceeded 1.5 C above the 1750 baseline. According to a comprehensive overview published by European Strategy and Policy Analysis System in April 2019, an “increase of 1.5 degrees is the maximum the planet can tolerate; … at worst, [such a rise in temperature above the 1750 baseline will cause] the extinction of humankind altogether.” Earth’s global-average temperature hit 1.73 C above the 1750 baseline by April, 2018. In other words, human extinction via the death-by-a-thousand-cuts route might be locked in with no further global-average heating. With that in mind, I proceed to a stunningly brief explanation of the McPherson Paradox.

Civilization is a heat engine, regardless how it is powered, a conclusion based on the Laws of Thermodynamics and reported in peer-reviewed articles by Professor Tim Garrett. As I have pointed out previously, a paper by Burke and colleagues published 10 December 2018 in the customarily conservative, peer-reviewed Proceedings of the National Academy of Sciences indicates “climates like those of the Pliocene will prevail as soon as 2030” (mid-Pliocene temperatures were 2-3 C warmer than today). Never mind that the Representative Concentration Pathways (RCPs) overlook a few dozen self-reinforcing feedback loops and the aerosol masking effect: Any informed look at RCPs will reveal the rapidity with which global overheating makes them obsolete. As a conservation biologist, I cannot imagine habitat will remain for humans–or many other species, for that matter–in the face of such rapid environmental change.

Civilization is a heat engine, but slowing or stopping civilization heats Earth even faster than the ongoing planetary heating resulting from this set of living arrangements. The impact of the aerosol masking effect has been greatly underestimated, as pointed out in this 8 February 2019 article in Science and then again in the 18 July 2019 issue of Geophysical Research Letters. As indicated by the lead author of the former paper during an interview on 25 January 2019: “Global efforts to improve air quality by developing cleaner fuels and burning less coal could end up harming our planet by reducing the number of aerosols in the atmosphere, and by doing so, diminishing aerosols’ cooling ability to offset global warming.” The cooling effect is “nearly twice what scientists previously thought.” That this February 2019 paper cites the conclusion by Levy et al. (2013) indicating as little as 35% reduction in industrial activity drives a 1 C global-average rise in temperature suggests that as little as a 20% reduction in industrial activity is sufficient to warm the planet 1 C within a few days or weeks. It’s worse than that, of course: a paper published in the 25 June 2021 issue of Nature Communications cited the previous papers and concluded global heating is reduced by 55% as a result of aerosol masking.

Loss of aerosol masking will quickly warm the planet. However, the resulting impacts on humans must be mediated through the reaction of other organisms. The life cycle of all plants, including crops, follows seasonal patterns. As a result, immediate warming of Earth will not cause immediate loss of habitat for human animals.

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Thanks to Bill R. Eddy for coining the term, “McPherson Paradox.” I know Bill via social media as well as his generous PayPal donations.