Editor’s note: As November’s global climate conference in Glasgow draws near, important facts about climate change don’t always make it into the dominant media coverage. We’re here to help. Each Thursday contributor
will provide some important background so readers can have a better understanding of the true effects of climate change and the real costs of climate policy.
It’s easy to construct climate disasters. You just find a current, disconcerting trend and project it into the future, while ignoring everything humanity could do to adapt. For instance, one widely reported study found that heat waves could kill thousands more Americans by the end of the century if global warming continues apace—but only if you assume people won’t use more air conditioning. Yes, the climate is likely to change, but so is human behavior in response.
Adaptation doesn’t make the cost of global warming go away entirely, but it does reduce it dramatically. Higher temperatures will shrink harvests if farmers keep growing the same crops, but they’re likely to adapt by growing other varieties or different plants altogether. Corn production in North America has shifted away from the Southeast toward the Upper Midwest, where farmers take advantage of longer growing seasons and less-frequent extreme heat. When sea levels rise, governments build defenses—like the levees, flood walls and drainage systems that protected New Orleans from much of Hurricane Ida’s ferocity this year.
Nonetheless, many in the media push unrealistic projections of climate catastrophes, while ignoring adaptation. A new study documents how the biggest bias in studies on the rise of sea levels is their tendency to ignore human adaptation, exaggerating flood risks in 2100 by as much as 1,300 times. It is also evident in the breathless tone of most reporting: The Washington Post frets that sea level rise could “make 187 million people homeless,” CNN fears an “underwater future,” and USA Today agonizes over tens of trillions of dollars in projected annual flood damage. All three rely on studies that implausibly assume no society across the world will make any adaptation whatever for the rest of the century. This isn’t reporting but scaremongering.
You can see how far from reality these sorts of projections are in one heavily cited study, depicted in the graph nearby If you assume no society will adapt to any sea-level rise between now and 2100, you’ll find that vast areas of the world will be routinely flooded, causing $55 trillion in damage annually in 2100 (expressed in 2005 dollars), or about 5% of global gross domestic product. But as the study emphasizes, “in reality, societies are likely to adapt.”
By raising the height of dikes, the study shows that humanity can negate almost all that terrible projected damage by 2100. Only 15,000 people would be flooded every year, which is a remarkable improvement compared with the 3.4 million people flooded in 2000. The total cost of damage, investments in new dikes, and maintenance costs of existing dikes will fall sixfold between now and 2100 to 0.008% of world GDP.
Adaptation is much more effective than climate regulations at staving off flood risks. Compare the two types of policies in isolation. Without any climate mitigation to help, dikes would still safeguard more than 99.99% of the flood victims you’d see if global warming continued on current trends. Instead of 187 million people flooded in 2100, there would be only 15,000. Climate policy achieves much less on its own. Without adaptation, even stringent regulations that keep the global temperature rise below 2 degrees Celsius would reduce the number of flood victims only down to 85 million a year by the end of the century.
Stringent climate policy still has only a mild effect when used in concert with dikes: Instead of the 15,000 flood victims you’d get with only adaptation, you’d have 10,000. And getting there would cost hundreds of trillions of dollars, which is hardly mitigated by the $40 billion drop in total flood damage and dike costs climate regulations would achieve. As I’ve explained in these pages before, this kind of policy has a high human cost: the tens of millions of people pricey climate regulations relegate to poverty.
You don’t have to portend doom to take climate change seriously. Ignoring the benefits of adaptation may make for better headlines, but it badly misinforms readers.
Mr. Lomborg is president of the Copenhagen Consensus and a visiting fellow at the Hoover Institution. His latest book is “False Alarm: How Climate Change Panic Costs Us Trillions, Hurts the Poor, and Fails to Fix the Planet.”
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Appeared in the October 21, 2021, print edition.