"The well-established scientific consensus that human activity is causing the climate to change does not extend to judgments about severity. The most comprehensive and often-cited efforts to synthesize the disparate range of projections—for instance, the United Nations’ Intergovernmental Panel on Climate Change (IPCC) and the Obama administration’s estimate of the “Social Cost of Carbon”—consistently project real but manageable costs over the century to come. To be sure, more speculative worst-case scenarios abound."
"Catastrophism can also lead to the trampling of democratic norms. It has produced calls for the investigation and prosecution of dissenters and disregard for constitutional limitations on government power. In The Atlantic, for example, Peter Beinart offered climate change as his first justification for an Electoral College override of the election of Donald Trump as U.S. president."
"Catastrophists typically condemn fracked natural gas because, although it results in much lower greenhouse-gas emissions than coal, it does not move the world toward the zero-emissions future necessary to avert climate change entirely. Yet fracking has done more in recent years to reduce carbon-dioxide emissions in the United States than all renewable energy investments combined. It has boosted U.S. economic growth as well."
"A strong scientific consensus holds that human activity is producing climate change. But from that starting point, scientists have produced a range of estimates in response to a variety of complicated questions: How quickly will greenhouse gases accumulate in the atmosphere? What amount of warming will any given accumulation cause? What effect will any given level of warming have on ecosystems and sea levels and storms? What effect will those changes in the environment have on human society? The answers to all of these questions are much debated, but broad-based efforts to synthesize the best research in the physical and social sciences do at least offer useful parameters within which to assess the nature of the climate threat.
On scientific questions, the gold-standard summary is the Assessment Report created every few years by thousands of scientists under the auspices of the United Nations’ Intergovernmental Panel on Climate Change (IPCC). By averaging widely varying projections and assuming no aggressive efforts to reduce greenhouse-gas emissions, they estimate an increase of three to four degrees Celcius (five to seven degrees Fahrenheit) by the year 2100. The associated rise in sea levels over the course of the twenty-first century, according to the IPCC, is 0.6 meters (two feet).
Most of the rise in sea levels results not from melting glaciers, but from the thermal expansion of ocean water as it becomes warmer. Melting ice from Greenland and Antarctica, which may eventually threaten a dramatic increase in sea levels, will barely begin in this century—in the IPCC analysis, the Antarctic ice sheet will have almost no effect and may even slow sea level rise as increased precipitation adds to its snowpack. Meanwhile, melting from Greenland’s ice sheet will contribute 0.09 meters (3.5 inches). In fact, “the near-complete loss of the Greenland ice sheet,” which could raise sea levels by seven meters, the IPCC reports, “would occur over a millennium or more.”
What about ecology? Predicting or quantifying damage to vulnerable ecosystems and specific species is notoriously difficult, but the IPCC offers a helpful heuristic for the likely magnitude of damage from climate change: “With 4°C warming, climate change is projected to become an increasingly important driver of impacts on ecosystems, becoming comparable with land-use change.” In other words, the impact should be similar to that which human civilization has imposed on the natural world already. Substantial and tragic, to be sure; but not something that modern society deems intolerable or a threat to human progress.
Economic tools called “integrated assessment models” attempt to convert the potential effects of climate change—on sea level and ecosystems, storms and droughts, agricultural productivity, and human health—into tangible cost estimates. This exercise is as much art as science, but it represents the best available exploration of how the impacts of climate change will likely stack up against society’s capacity to cope with them. Three of these models form the basis of the Obama administration’s analysis of the “Social Cost of Carbon”—the U.S. government’s official estimate of how much climate change will cost and thus what benefits come from combatting it. Economists and policymakers who want to place a price (that is, a tax) on carbon-dioxide emissions to force emitters to pay for potential damage resulting from climate change typically embrace the analysis as well.
According to the assessment models, a warming of three to four degrees Celcius by 2100 will cost the world between one and four percent of global GDP in that year. To put the high end of that range concretely, the Dynamic Integrated Climate-Economy (DICE) model developed by economics professor William Nordhaus at Yale University estimates that in a world without climate change, the global economy’s GDP would grow from $76 trillion in 2015 to $510 trillion in 2100 (an annual growth rate of 2.3 percent). A rise in temperatures of 3.8 degrees Celcius would cost 3.9 percent of GDP ($20 trillion) that year, effectively reducing GDP to $490 trillion.
Twenty trillion dollars is a very large number—representing a cost greater than the entire annual economic output of the United States in 2016. But from the perspective of 2100, such costs represent the difference between the world being 6.5 times wealthier than in 2015 or 6.7 times wealthier. In the DICE model, moreover, the climate-change-afflicted world of 2105 is already more prosperous than the climate-change-free world of 2100. And because the impacts and costs of climate change emerge gradually over the century—0.3 percent of GDP in 2020, 1.0 percent in 2050—in no year does the model foresee a reduction in economic growth of even one-tenth of a percentage point. Average annual growth over the 2015–2100 period declines from 2.27 percent to 2.22 percent."
"Among the three models the Obama administration picked for its analysis alone, the range of outputs is enormous: the DICE model’s four percent-of-GDP estimate is near the 95th percentile of the projections from the middle-case model, while the low-case model’s one percent-of-GDP estimate is below the middle-case’s 5th percentile. But nowhere is catastrophe to be found."
"the societal collapse that catastrophists envision—one that poses an “existential” threat beyond the scope of other human problems, one that makes procreation an ethically dubious proposition—is simply irreconcilable with the outlook the science and economics offers."
"what if, rather than not caring about their grandchildren, people have confidence that their grandchildren will enjoy a far higher standard of living and have a greater capacity to cope with whatever climate change might bring? In purely economic terms, both seem likely. Even after accounting for climate change, the DICE model forecasts a world 6.5 times richer than today’s for a population only 40 percent larger. Condemn mainstream economic estimates as hopelessly optimistic, increase the annual cost estimate for 2100 tenfold from $20 trillion to $200 trillion, and the world is still four times richer than today."
"Environmentalists, for example, have long worried about global population outstripping food supply. In 1970, the biologist Paul Ehrlich warned that, due to population growth, “at least 100-200 million people per year will be starving to death during the next ten years.” Instead, a technological revolution caused agricultural yields to surge. Today, even as concern grows about potential water crises around the world, the seeds of their resolution may be sprouting as well. Israel, suffering from the same drought often blamed for helping plunge Syria into civil war, is using desalination technology to make the desert bloom. Recently, it found itself with a water surplus. India is constructing more than one million irrigation ponds that will increase agricultural yields by as much as 300 percent and buffer against changes in the timing of the monsoon season."
"Richer countries experience significantly lower fatality rates from natural disasters and also significantly lower damages relative to the size of their economies. The World Health Organization reports that in the three cyclones of maximum severity striking Bangladesh in 1970, 1991, and 2007, total fatalities declined from 500,300 to 138,958 to 4,234. The diffusion of existing technologies worldwide, and the development of new ones—coupled with unprecedented resources for implementation—should ensure that these trends continue."
"Take, for instance, the EPA’s “Climate Change Risks and Analysis” project. Among its most prominent claims: Unmitigated climate change will cause more than 12,000 annual deaths from extreme heat in major U.S. cities by 2100. (The U.S. Centers for Disease Control and the EPA report fewer than 500 heat-related deaths in 2014, a figure that has been on a downward trajectory over the past 15 years). To reach 12,000 by 2100, the analysis took each city’s mortality rate from extreme heat in 2000 and applied it to the hotter temperatures forecast for 2100. It concluded that, by 2100, the heat in New York City would be killing at 50 times the rate in Phoenix in 2000 (even though the New York City of 2100 is not expected to be as hot as the Phoenix of 2000). If one believes that residents of New York City will be dropping like flies from heat in the future, climate change must seem terrifying indeed. But that is not a rational belief."
"even if fully half of global agricultural production must relocate over a century, the required shift each year is only 0.5 percent of total production. For comparison, annual additions to global food production have averaged more than two percent over the past 50 years."
"Even stipulating that adaptations will displace hundreds of millions of people, that displacement will not happen all at once. Spread over decades, such a disruption would look little different from the status quo. China alone currently supports a domestic migrant worker population of 278 million. According to estimates by the United Nations, there are currently 232 million international migrants. The organization projects that the figure will grow by several million each year. By 2050, the World Bank estimates that 2.5 billion people will migrate to cities for reasons unrelated to climate change."
"If people allocating capital—be they small-town farmers, resort designers, or mayors—have the information and incentives to incorporate climate adaptation into their planning, it need not impose sudden and unmanageable recovery costs."
"Although climate impacts may be permanent and on-going, costly adaptation—if done wisely—need occur only once. A Manhattan properly insulated from rising waters will not require new protection each time sea level climbs another foot. Conversely, that hypothetical $20 trillion represents the resources that society might commit to the problem in the single year 2100. In Nordhaus’ DICE model, the total allocated to climate costs between 2050 and 2150 is more than $2.5 quadrillion, all without ever slowing annual growth by more than one-tenth of one percentage point. The world’s productive capacity, bolstered by innovation and adaptation over time, is orders of magnitude larger than the demands climate change is expected to impose. Such adaptation may represent a tragic long-term drain on society’s resources, but that does not mean it will noticeably alter the trajectory of human civilization."
"Working with a catastrophic mindset and a century-long timeline, one can construct an apocalyptic scenario from almost any problem."
"the Global Priorities Project at Oxford observes that climate change could “render most of the tropics substantially less habitable than at present,” as compared to the hundreds of millions or billions of deaths associated with other challenges. Another Oxford study surveyed conference participants about the extinction-level risks of various catastrophes and neglected to even consider climate change; respondents gave molecular nanotechnology, superintelligent AI, and an engineered pandemic all at least a two percent chance of erasing humanity by 2100."
"arguments against catastrophism rarely reach the audience that might benefit most from hearing them."
"As Paul Romer, the chief economist of the World Bank, recently observed:
During the 1970s, the Club of Rome famously argued that our economic system was on the verge of collapse because we were running out of fossil fuel. This analysis was flawed not simply because it got the magnitudes wrong. It got the signs wrong. The problem facing the world is not that the earth’s crust contains too little fossil fuel and that we won’t have enough innovation to solve this problem. The real problems are that the earth’s crust contains far too much fossil fuel and that too much [innovation] is making this problem much worse.
In other words, even though the Club of Rome was wrong in the 1970s, Romer believes its broader perspective should be embraced. Seemingly oblivious to the irony, he attributes the failure last time around to “an instance of motivated reasoning. Advocates seem to have been too eager to generate a sense of pessimistic urgency.”
Schrag, the Harvard geology professor, is even more blunt. Reflecting on Ehrlich’s predictions of eminent mass starvation in the 1970s, Schrag acknowledges that “none of his predictions came true.” Nevertheless, says Schrag, “It’s quite amazing that we’re actually able to feed the world at all. Ehrlich wasn’t wrong in ’68, he’s just wrong today.” In this view, the catastrophist is not accountable for considering how growth, innovation, and adaptation might avert catastrophe. But Ehrlich was indeed wrong in 1968, for the same reasons his intellectual heirs are likely wrong about climate change today."
Friday, March 24, 2017
The Problem With Climate Catastrophizing
By Oren Cass in Foreign Affairs. Oren Cass is a senior fellow at the Manhattan Institute, where he focuses on energy, the environment, and antipoverty policy. Excerpts: