THE CLIMATE IS CHANGING? SHOW ME THE DATA-Part 2

Part 2: Extreme and costly events, attributable in part to the warming planet, are increasing in frequency and intensity

The warming of the planet is worrisome because it is producing recognizable, strong climate change impacts with severe consequences for human health and welfare. This second installment in our three-piece series suggests ways to read, understand and communicate figures from climate studies that focus attention on the consequences of observed climate-driven risks.

To people who are paying attention to current events, it would seem that the list of climate-related impacts that can be attributed to higher global mean surface temperatures is growing nearly every day. The cover figure above shows how, in its Sixth Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) organized this ever-expanding list. It was combined into four categories: water availability/food production, health and well-being, cities, settlements and infrastructure, and biodiversity and ecosystems. In the figure, circles with red backgrounds indicate global adverse effects; grey circles are observed effects with no global assessment; and red/grey circles, observed negative and positive effects agreement on sign.

Each category identifies a distinct macro-scale context, and that is helpful in revealing what we do and do not yet know about effects on public welfare. The value of identifying large categories can be further understood if the underlying content is explored. Consider, for example, what falls under “Cities, settlements, and infrastructure”. Figure 1, in three panels, presents data collected by the U.S. National Oceanographic and Atmospheric Administration (NOAA) for its annual reports on Billion-dollar Weather and Climate disasters.

Panel A depicts the locations of 27 of the billion-dollar (or more) events that occurred in 2024 – one shy of the historical record that was set in 2023.

Figure 1 – Panel A. Billion-dollar weather and climate disasters across the United States in 2024. The icons displayed on the map show the locations and dates for 27 weather/climate disasters.

These events include:

• 2 winter storm/cold wave events (across the Northwest and central/southern U.S. in mid-January);

• 1 wildfire event (the South Fork Fire in New Mexico that destroyed many homes, vehicles, businesses and other infrastructure);

• 1 drought and heat wave event (causing impacts across the southern, eastern and northwestern U.S.);

• 1 flooding event (the Upper Midwest Flooding in mid-June across several states).

• 6 tornado outbreaks (across the central and southeastern U.S.);

• 5 tropical cyclones (Beryl, Debby, Francine, Helene and Milton – the final two were the costliest U.S. disasters of 2024); and

• 11 severe weather/hail events (across many parts of the country).

Panel B displays monthly patterns in billion-dollar disasters since 1980. The numbers in parentheses in the caption highlight the six years with the highest total number of such events, indicating where those years lie in the ranking of global mean surface and/or ocean temperature shown in Figures 1 and 2 in Part 1 of this collection. Five of the six (not 2011) were experienced within the last 7 years, which are among the warmest 10 years on record.

Figure 1 – Panel B. The monthly incidence of billion-dollar disasters for the six most turbulent years since 1980. The six years with the most damaging climate-related episodes listed from the top down in annual number of billion-dollar disasters are portrayed: 2023 (28), 2024 (27), 2020 (22), 2021 (20), 2017 (19), and 2022 (18).

Finally, Panel C plots monthly accumulations of damages from January through December over the same time period. They are expressed in real terms to account for the effects of 240% inflation over the past 45 years. The total cost of U.S. billion-dollar disasters over the last 5 years (2020-2024) is $747 billion. That total reflects and average of $149 billion, twice the $65 billion 45-year average from 1980 through 2024.

Figure 1 – Panel C. The accumulated monthly incidence of billion-dollar disasters for the six most turbulent years since 1980. Month-by-month accumulation of estimated annual costs of billion-dollar disasters.

What will the 2025 data look like? This past January the California wildfires were estimated to have caused between $76 and $131 billion in property and capital losses (with insured losses up to $45 billion) plus $5 billion in lost GDP. These estimates do not include exploding insurance premiums for those policies that are still available and dramatic increases in rental fees to clear local markets with with an extraordinarily scarce supply of habitable units.[1] As a result, the cumulative plot for 2025 could begin in January well over $100 billion – 25 times the historical record for January billion dollar catastrophes for the entire country.

These data had been released every month and summarized every year since 1980. They have already shown that climate-driven natural disasters have increased in intensity and frequency over the past decade or so, but I was already worried that increased frequency of noteworthy events has numbed the public’s sensitivity to even horrific. Now I worry even more. If these events blend together over time and there is no place to go to see consolidated records, then they can become expected as a matter of course or they and fall quickly out of mind because it is easier to live that way.

On the fourth of July, the Texas hill-country suffered a catastrophic flash flooding event that cost more than 110 lives as of July 8^th with 160 others missing. On July sixth, I heard a local leader say in a television interview something like “How could this have been expected? Nothing like this has ever happened before – 26 feet river rise in less than an hour was unimaginable.” Except that it happened last year on September 24^th in Asheville, North Carolina – with the French Broad River increasing the previous 15 foot record high flow by more than another 10 feet.

This is why I worry that society’s ability to grasp the seriousness of growing climate risks will fade despite our communicating the evidence that extreme events are becoming not only more frequent but also more consequential. We have to do a better job presenting the past because we have a gap to fill.

The third part of this series will follow in a few days with evidence that we can also do a better job presenting what might happen in the future.

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[1] For these recently up-dated cost estimates, see https://www.anderson.ucla.edu/about/centers/ucla-anderson-forecast/economic-impact-los-angeles-wildfires; and, for a revealing chronical of life in the fire zone over the past 6 months, see https://laist.com/brief/news/climate-environment/six-months-after-fires.

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Gary Yohe is the Huffington Foundation Professor of Economics and Environmental Studies (emeritus), Wesleyan University.