COP21 in Paris is fast approaching and the #BigPush is on. That means we’re forced to talk about global warming more than I’d like (which is not at all). But it’s necessary.
Let’s decide if this is over-reach, hubris, rank enthusiasm, or possibly a measure of all three. Paper is the peer-reviewed “Global non-linear effect of temperature on economic production” by Marshall Burke, Solomon M. Hsiang, and Edward Miguel in Nature.
The internal alarms in readers with math will have begun. Did they say non-linear? Yes, sir, they did. To readers without math, all you need know is that non-linear models are as sensitive as feminists. The least little thing sets them rocketing away in unexpected directions.
Say, have economists been able to identify the linear and non-linear non-temperature effects of the economy, such that they make successful predictions? No, sir, they have not. Then why are we bothering with this?
TRIGGER WARNING Here’s the first sentence of the abstract. “Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent.”
Regular readers (whom I hope were not drinking while reading) will recognize this as scientism of the first kind, which is not to acknowledge what has always been blazingly obvious to all of mankind unless it has been certified by puzzled scientists. Good grief! My folks figured this bit of atmospheric physics out years ago when they began yearly migrations from Michigan to Florida after the first flurries fly. Climate refugees.
More from the abstract: “These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications.”
I guess we now know why the economic activity associated with growing grapes is missing from Tierra del Fuego. Too much linearity, or something. And did you notice the key phrase? This is it: economic loss in response to climate change. This is an admission of blindness. These scientists are incapable of recognizing that good can come from “climate change,” even though everybody knows that increased carbon dioxide must be beneficial for plant life.
Incidentally, as I’ve relentlessly insisted, don’t say “climate change”, say “global warming.” They promised us global warming. We can’t let them forget that. Since the climate will always change, anything that happens—and things will happen—will be an excuse for governmental meddling.
Then comes the model. “We use our results to construct an empirical ‘damage function’ [there’s that bias towards doom again] that maps global temperature change to global economic loss by aggregating country-level projections. Damage functions are widely used in economic models of global warming…”
This isn’t reality, it’s a model. It has some pretty math, wee p-values, knobs to twist, and other trappings standard in these kinds of things. Yet the authors commit the banal fallacy of assuming their model has identified causes of the economy.
That temperature, say, effects the economy everybody already knew, and they knew it in a causal sense. There are no ski slopes in Boca Raton because of the lack of snow. Thus the economic sales of trail-grooming machines there is low. But the authors of this paper don’t mean cause in this humble (but true) sense. Instead, they think they have identified how temperature causes non-linear changes in gross domestic product, which isn’t a thing but is instead a sum of billions (trillions?) of small things.
The figure above is from the paper and represents “Change in GDP per capita (RCP8.5, SSP5) relative to projection using constant 1980–2010 average temperatures.” Except for Europe, North America, and Central and East Asia, the economies of the world essentially end by 2100. This is what 75%-90% reductions in GDP mean. Europe, enlightened as always, is the only region which prospers. Conclusion?
If societies continue to function as they have in the recent past, climate change is expected to reshape the global economy by substantially reducing global economic output and possibly amplifying existing global economic inequalities, relative to a world without climate change.
In their favor, these authors made testable, public predictions. We’ll be able to check their model for accuracy. This is how science is supposed work. But I think anybody who claims to believe this model is lying.
Strong words, right? Okay, believers, prove me wrong. Invest right now, using your money, in the model’s conclusions. Bet big. And (not that I don’t trust you) show me your receipts. If the model is good, you’ll clean up.