Wednesday, February 08, 2012

Insights from Past Millennia on the Health Impacts of Climate Change

From Mr. Lalloobhoy Battliwala

Anthony J McMichael PNAS paper "Insights from past millennia into climatic impacts on human health and survival" attached. Abstract below.

Except for the last sentence in the abstract, "Duh!!"

Is this science? It certainly ain't history. Collection of anecdotal tidbits, that's all.

But nor is it a uni-dimensional, deterministic tract the abstract made me afraid. (I have read McMichael's review papers before.)

It's a cautiously written paper, and I am of course unable to judge the validity of historical references. At times, however, I feel like his caution gives it a sophomoric tone - e.g. "Great civilizations decline for complex reasons"; of course, so why make grandiose claims?

As generally with mechanistic Models of Doom (see attached Solow piece from PNAS 1972), scientists ignore the role of prices and political power.

"The greatest recurring health risk has been from impaired food yields, mostly due to drying and drought. The fact that drought has been the dominant historical cause of hunger, starvation, and consequent death (70) casts an ominous shadow over this coming century, for which climate modeling consistently projects an increase in the range, frequency, and intensity of droughts (71)."

Yeah, yeah. But how droughts become famines is the interaction of human ingenuity, control, deviousness.

McMichael quotes Mike Davis' Late Victorian Holocausts (footnote 66) but only to report out-of-context statistics.

Climate scientists like Trenberth assert all other scientists should refrain from challenging their climate dogma and stick to their discipline. Perhaps epidemiologists shouldn't pretend to be historians and philosophers. Or climate scientists, for that matter.

The last sentence in the Abstract is nonsense; it is cheaper to more directly address the climate-related health vulnerability.

Grow more food and distribute it efficiently. Address food insecurity, forget climate change abatement.


Anthony J. McMichael, Feb 6,2012,
Proceedings of the National Academy of Sciences

Climate change poses threats to human health, safety, and survival via weather extremes and climatic impacts on food yields, fresh water, infectious diseases, confl ict, and displacement. Paradoxically, these risks to health are neither widely nor fully recognized. Historical experiences of diverse societies experiencing climatic changes, spanning multicentury to single-year duration, provide insights into population health vulnerability— even though most climatic changes were considerably less than those anticipated this century and beyond. Historical experience indicates the following. (i ) Long-term climate changes have often destabilized civilizations, typically via food shortages, consequent hunger, disease, and unrest. (ii) Medium-term climatic adversity has frequently caused similar health, social, and sometimes political consequences. (iii) Infectious disease epidemics have often occurred in association with briefer episodes of temperature shifts, food shortages, impoverishment, and social disruption. (iv ) Societies have often learnt to cope (despite hardship for some groups) with recurring shorterterm (decadal to multiyear) regional climatic cycles (e.g., El NiƱo Southern Oscillation)— except when extreme phases occur. (v ) The drought– famine – starvation nexus has been the main, recurring, serious threat to health. Warming this century is not only likely to greatly exceed the Holocene’ s natural multidecadal temperature fluctuations but to occur faster. Along with greater climatic variability, models project an increased geographic range and severity of droughts. Modern societies, although larger, better resourced, and more interconnected than past societies, are less flexible, more infrastructure-dependent, densely populated, and hence are vulnerable. Adverse historical climate-related health experiences underscore the case for abating human-induced climate change.

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