It’s not unusual to see headlines like this in health journalism:
Antibiotic Resistance Is Now as Big a Threat as Climate Change
To be fair, the article itself is not nearly so hysterical; in fact it doesn’t even mention climate change. Yet some editor thinks that this nonsense is an appropriate way to summarize the threat that AMR does indeed pose to human health.
Ten seconds of reflection is all that’s required to see why this is bullshit: if antibiotics fail, the worst-case scenario is that we are set back to 1940; if the climate fails, we are set back to 1940 BCE. Or maybe 19,400 BCE.
In the last 200 years, humans—for the first and only time since the invention of agriculture—escaped Malthus’ Trap. Despite the substantial technological progress that drove us through Stone, Bronze and Iron Ages and to the Age of Discovery, the living standards of the average person progressed not at all. Every increase in food production was literally eaten up by increased population, leaving the average human no better off than before. Here, in a single chart, is the economic history of mankind:
This increase in wealth coincided with both an increase in urbanization…
…and (with a lag) an increase in life-expectancy
My point here is that these three things—wealth, urbanization, long life—characterize the modern age and distinguish it from all previous ages. All are interdependent, and all are in turn dependent on an effective public health system.
You can’t have an innovative, wealth-generating economy without cities. You can’t have sustainable urbanization without high life-expectancy. You can’t have high life-expectancy without effective public health. And you can’t have effective public health without sufficient wealth to pay for the infrastructure required. Knock out any one of these elements and the others will crash also.
Climate change threatens each one of these elements.
Large cities tend to be on coastlines or along major rivers. These coastal regions are the main generators of wealth. In the US, roughly half of the nation’s $19.5T GDPwas generated in coastal counties, despite their hosting only 29% of the US population.
Rising seas put these centers of wealth generation at risk, destroying many billions of dollars of civic capital as well as diverting many billions more to mitigation efforts.
From When Rising Seas Hit Home
Dealing with this problem alone—abandoning much of the most economically productive infrastructure in the country and rebuilding it anew—will be a huge challenge. But of course it won’t be the only challenge. It won’t even be the biggest challenge.
That honor will go to the disruption of agriculture. Increases in extreme weather along with general temperature increases will combine to create serious reductions in crop yields at a time when the world’s population is expected to grow by another 2B people
Agriculture is a fairly recent invention, popping up in a few places around the globe in the last 5000-10,000 years. The invention of agriculture coincided with the appearance of a moderate and consistent climate regime:
Here is a close-up of the last 11,000 years
In short, agriculture–the only conceivable means to feed billions of people–has existed only in a unusually stable and moderate climate regime. We are well on the way to shooting past the previous bounds of that regime, and the effects on agricultural productivity are already apparent:
Of course those losses will not be evenly distributed:
On average, that’s pretty bad. In practice it’s worse. Survival doesn’t depend on eating an adequate amount of food on average. It depends on eating an adequate amount of food every day. Small losses in average food production mask big changes in daily food availability. When widespread crop failures occur, starving people will not quietly accept their fate (nor should they). They will demand relief from local governments, which will often be unequal to the task, resulting in political upheaval and civil war. That disruption, coupled to food shortages will trigger large-scale migrations to the green areas in the map above.
We are already seeing this: the Syrian civil war and subsequent migration were triggered by drought and crop failure; the current surge in migration from Central America is coming from the areas most vulnerable to climate change. The political instability engendered by fleeing refugees extends to their presumed refuges, where anti-immigrant backlash disrupts and undermines established liberal political order.
What happens when the number of climate refugees swells from a few million to tens and then hundreds of millions? Is there any chance that well-ordered governance survives anywhere on the globe? I think not. And when governments—already strained by internal climate challenges—collapse, what happens to public health infrastructure? Who maintains the supply of clean drinking water? What happens to sanitation districts? How are vaccination programs maintained? How do we deal with insect vectors expanding their range? How do we contain outbreaks of contagious diseases, both new and old?
The answer is that we can’t and we won’t. People get exercised by the threat of anti-microbial resistance as a threat to public health, as they should. But the worst-case scenario for AMR is that we go back to 1940. The worst-case scenario for climate change is that we go back to 1940 BCE, and back into Malthus’ Trap.