Class News
Sam Francis ’64 on global warming
Apocalypse on the Horizon
August 14, 2020
by Sam Francis ’64
At the current rate of burning fossil fuels and releasing carbon dioxide to the atmosphere, the global average temperature will rise by 4⁰C (7⁰F) by the end of this century, relative to the pre-industrial era. This prediction comes from many well-validated, well-accepted climate models based on ocean and climate physics. The science is settled. The time for questioning human-caused global warming is long past. Now the only questions are how devastating it will be, and what to do about it.
In the UN Paris Agreement of 2015, world leaders vowed to hold global temperature rise well below 2⁰C. However, they have failed to deliver. Since the 2015 agreement, emissions have increased every year. Unless there’s a radical change, a rise of 4⁰C will occur by the year 2100, perhaps earlier. Even 5⁰C or 6⁰C may be possible if we’re unlucky with positive feedbacks.
What are the implications?
It’s true that 4⁰C is a small, single-digit number, but don’t be deceived. Experts say that at 3⁰C the stability of human civilization will be seriously imperiled, whereas at 4⁰C a full-scale global collapse of human societies is probable, accompanied by a mass extinction of the biosphere exceeding all extinctions in the fossil record since the Cretaceous.
This prediction may sound exaggerated and alarmist but, based on the science, it is not. Here’s how it would happen, and what such a world would look like.
The increase in temperature will not be uniform over the globe, but will be much more extreme over land areas. For example, Ellesmere Island, inside the Arctic Circle with current winter temperatures of minus 40⁰C (-40⁰F), will experience temperatures of 14⁰C (57⁰F), similar to the northern half of the British Isles today. Ellesmere has not been this warm since the Pliocene, four million years ago, well before humans existed. That may be good news for Ellesmere, but bad news for temperate and tropical regions where there are large populations.
For example, in the southern United States large areas will experience peak temperatures exceeding those in Death Valley, the hottest place on earth, which reached a record 130⁰F two days ago. This extreme heating has already begun all across the south. Average temperatures in Las Vegas, for example, have risen 3.2⁰C (5.8⁰F) since 1970. That’s not an anomaly. This temperature increase is not only continuing, but accelerating.
In the tropics, 140 million people will experience conditions above the “heat survivability threshold” at which humans perish because they cannot regulate body temperature by sweating, owing to the combined effects of heat and humidity. What’s more, over a billion people will experience temperatures exceeding the “workability threshold” above which it becomes impossible to safely work outside, even in the shade.
With the inability to work outside, subsistence and smallholder farming will be eliminated in almost all of Africa and South Asia, destroying the livelihoods of more than a billion people.
The Mediterranean regions will experience drastic precipitation decline. Large areas will not have sufficient water to maintain their current populations without relying on desalinated seawater. In these regions, rainfed farming will largely cease to exist.
Wildfires will devastate croplands, pasturelands, grasslands, forests, towns and villages. By the end of the century, global food production will be cut in half, as the world population rises to 11 billion. This is a recipe for mass starvation.
The warming polar regions will release meltwater, raising mean global sea levels by up to a meter, inundating land currently inhabited by 108 million people. The warming of the north polar regions will also cause permafrost to melt, releasing large quantities of methane, a greenhouse gas with a warming potential 28 times that of carbon dioxide, accelerating the temperature rise.
Where will all the refugees from heat, fires, flood, and famine go?
Since most of the human population is in the northern hemisphere, most climate refugees will flee northwards, seeking shelter and survival in cooler regions, overwhelming the resources and good will of their northern neighbors. The refugees are unlikely to be welcomed. National borders and defensive perimeters will not present much of an obstacle.
This northward exodus will be accompanied by a northward migration of agriculture, seeking conditions where crops can grow. Agriculture will attempt to shift into Arctic Canada, Alaska, Siberia, and Scandinavia. But most northern polar regions have thin, rocky soils with little prospect of yielding much harvest. And in the Southern Hemisphere the option of shifting crop production poleward is not available at all, because the continents diminish in size toward the higher latitudes, with barely any new land to farm.
Carbon dioxide accumulating in the atmosphere will remain there for many hundreds of years, continuing to drive up global temperatures for centuries even if future emissions are controlled.
Will humanity have the foresight and the will to avoid this fate by reducing or eliminating carbon emissions? Or will our destiny be sealed before most of us even acknowledge that there’s a problem worth solving?
Time is not on our side. A radical change is needed, before it’s too late.
This essay is based in large part on Our Final Warning: Six Degrees of Climate Emergency by Mark Lynas (HarperCollins UK, 2020, 368 pp), and on A World Without Ice by Henry Pollack (Avery/Penguin, 2009, 287 pp).
Other essays by Sam Francis on this website include Facts Matter, A Universe From Nothing, EMS in the Time of Coronavirus, Evolution ... From Soup to Nuts, and On Racism (Empathy for President Salovey).
Sam Francis, Yale ’64, holds a PhD in physics from Harvard followed by a 29-year career at Bell Labs and 7 years as a technology strategy consultant for the Science and Technology Directorate of the U.S. Department of Homeland Security. He has served as a volunteer EMT for 19 years and is currently the Senior Deputy Emergency Coordinator for his hometown of Chatham, NJ.
Your comments are welcome. Email Sam at sfrancis@fast.net.