5 Key Moments That Forced Americans to Confront Climate Change – History
Almost two centuries after the discovery that gases in Earth’s atmosphere help warm the planet’s surface, public polling has found that more than half of Americans believe climate change poses a “critical threat” to the country’s vital interests, an increase of 10 percentage points from a June 2017 poll and six points from March 2019. U.S. public resistance to the science of climate change and the behavioral changes required to combat it has been particularly persistent relative to much of the rest of the world; but over the last several decades, a number of events and discoveries have helped accentuate the issue’s importance. Here is a selection of some of key developments.
1. Early Evidence
The scientific rationale for global warming was established in the 19th century. Joseph Fourier discovered in 1824 that Earth would be colder without an atmosphere. John Tyndall determined in 1859 that carbon dioxide and water vapor block infrared radiation and that an increase in their atmospheric composition could induce warming. And in 1896, Svante Arrhenius published the first calculation of how much warming would be created by increased levels of carbon dioxide in the atmosphere.
But not until the second half of the 20th century did updated scientific assessments begin to permeate into public consciousness—albeit slowly at first. In 1958, Ralph Keeling began plotting levels of CO2 in the atmosphere from atop Mauna Loa in Hawaii, producing the famous Keeling Curve, which updates daily. (When he began, levels of CO2 in the atmosphere were 313 parts per million (ppm); by 2022 they were around 420 ppm.)
In 1965, scientists on the U.S. President’s Science Advisory Committee first put forward concerns about greenhouse warming, arguing that the continued release of CO2 into the atmosphere would “almost certainly cause significant changes” and “could be deleterious from the point of view of human beings.” And in 1983, back-to-back reports from the National Academy of Sciences and the Environmental Protection Agency sounded the alarm about rising greenhouse gas levels, with the EPA report warning that “Substantial increases in global warming may occur sooner than most of us would like to believe.”
2. Jim Hansen Testifies
In the wake of the EPA and NAS reports, and other growing evidence of the reality of greenhouse warming, Congress held a number of hearings on the issue and invited the testimony of outside experts. The most impactful came on June 23, 1988 when, on a hot day in Washington, D.C., James Hansen of the NASA Goddard Institute of Space Studies told senators that, “The earth is warmer in 1988 than at any time in the history of instrumental measurements,” and that there was “only a 1 percent chance of an accidental warming of this magnitude … The greenhouse effect has been detected, and it is changing our climate now.” The New York Times declared that Hansen’s testimony “sounded the alarm with such authority and force that the issue of an overheating world has suddenly moved to the forefront of public concern.”
Scroll to Continue
3. ‘An Inconvenient Truth’
Following his razor-thin defeat in the 2000 U.S. Presidential election, Al Gore—who initiated the first congressional hearing on global warming in 1981—began presenting a slide show on the science and policy issues of climate change, which producer Laurie David and director David Guggenheim transformed into the documentary An Inconvenient Truth. The documentary, which was generally lauded by scientists for its accuracy, increased awareness of global warming and a willingness to take action to prevent it (even as it helped accentuate a growing partisan divide on the issue). It grossed more than $50 million worldwide at the box office and won the 2007 Academy Award for Best Documentary Feature. That same year, Gore shared the Nobel Peace Prize with the Intergovernmental Panel on Climate Change.
4. Hurricanes Katrina and Sandy
” data-full-height=”1333″ data-full-src=”https://www.history.com/.image/c_limit%2Ccs_srgb%2Cfl_progressive%2Ch_2000%2Cq_auto:good%2Cw_2000/MTU4MDczOTQxMzA5NTk3MTg4/2-hurricane-katrina-97268937.jpg” data-full-width=”2000″ data-image-id=”ci02319769b00026d5″ data-image-slug=”2-Hurricane-Katrina-97268937″ data-public-id=”MTU4MDczOTQxMzA5NTk3MTg4″ data-source-name=”Michael Appleton/NY Daily News Archive/Getty Images” data-title>
” data-full-height=”1261″ data-full-src=”https://www.history.com/.image/c_limit%2Ccs_srgb%2Cfl_progressive%2Ch_2000%2Cq_auto:good%2Cw_2000/MTU4MDczOTQxMzA5NTMxODYx/4-hurricane-katrina-55320265.jpg” data-full-width=”2000″ data-image-id=”ci02319769c00026d5″ data-image-slug=”4-Hurricane-Katrina-55320265″ data-public-id=”MTU4MDczOTQxMzA5NTMxODYx” data-source-name=”Marko Georgiev/Getty Images” data-title>
” data-full-height=”1281″ data-full-src=”https://www.history.com/.image/c_limit%2Ccs_srgb%2Cfl_progressive%2Ch_2000%2Cq_auto:good%2Cw_2000/MTU4MDczOTQxNTc4MDMyNjQ0/6-hurricane-katrina-97348363.jpg” data-full-width=”2000″ data-image-id=”ci02319769e00126d5″ data-image-slug=”6-Hurricane-Katrina-97348363″ data-public-id=”MTU4MDczOTQxNTc4MDMyNjQ0″ data-source-name=”Michael Appleton/NY Daily News Archive/Getty Images” data-title>
” data-full-height=”1272″ data-full-src=”https://www.history.com/.image/c_limit%2Ccs_srgb%2Cfl_progressive%2Ch_2000%2Cq_auto:good%2Cw_2000/MTU4MDczOTQxNTc4MDMyODUz/8-hurricane-katrina-54216822.jpg” data-full-width=”2000″ data-image-id=”ci02319769d00026d5″ data-image-slug=”8-Hurricane-Katrina-54216822″ data-public-id=”MTU4MDczOTQxNTc4MDMyODUz” data-source-name=”Mario Tama/Getty Images” data-title>
” data-full-height=”1333″ data-full-src=”https://www.history.com/.image/c_limit%2Ccs_srgb%2Cfl_progressive%2Ch_2000%2Cq_auto:good%2Cw_2000/MTU4MDczOTQxNTc4MTYzNzE2/10-hurricane-katrina-54243759.jpg” data-full-width=”2000″ data-image-id=”ci02319769d0002604″ data-image-slug=”10-Hurricane-Katrina-54243759″ data-public-id=”MTU4MDczOTQxNTc4MTYzNzE2″ data-source-name=”Dave Einsel/Getty Images” data-title>
” data-full-height=”1361″ data-full-src=”https://www.history.com/.image/c_limit%2Ccs_srgb%2Cfl_progressive%2Ch_2000%2Cq_auto:good%2Cw_2000/MTU4MDczOTQxNTc4MTYzOTI1/12-hurricane-katrina-120959540.jpg” data-full-width=”2000″ data-image-id=”ci02319769f0002604″ data-image-slug=”12-Hurricane-Katrina-120959540″ data-public-id=”MTU4MDczOTQxNTc4MTYzOTI1″ data-source-name=”Daniel J. Barry/WireImage/Getty Images” data-title>
” data-full-height=”1333″ data-full-src=”https://www.history.com/.image/c_limit%2Ccs_srgb%2Cfl_progressive%2Ch_2000%2Cq_auto:good%2Cw_2000/MTU4MDczOTQxNTc4Mjk0OTk3/14-hurricane-katrina-97285306.jpg” data-full-width=”2000″ data-image-id=”ci0231976a00002604″ data-image-slug=”14-Hurricane-Katrina-97285306″ data-public-id=”MTU4MDczOTQxNTc4Mjk0OTk3″ data-source-name=”Michael Appleton/NY Daily News Archive/Getty Images” data-title>
Scientists have long predicted that a major consequence of global warming will be an increase in the amount and severity of extreme weather events, and a series of them in the 21st century drove home the potential real-world impacts of a changing climate. In 2005 Hurricane Katrina flooded 80 percent of New Orleans, and killed an estimated 1,800 people. While it is not possible to assert that climate change directly caused the storm, one study concluded that increased ocean temperatures and sea levels likely accentuated the damage it caused. Similarly, higher sea levels almost certainly accentuated the storm surge from Superstorm Sandy, which struck the coast from Maryland north to Manhattan in 2012. A 2021 study concluded that climate change was responsible for at least $8 billion in damages caused by the storm.
From the Amazon to Australia to the American West, in 2020 the world caught fire—and climate change played a significant role. The southern Amazon saw nearly 600,000 individual fires, 25 of which were larger than 190 square miles in area, while approximately 28 percent of the Pantanal—a floodplain region along the borders of Brazil, Bolivia, and Paraguay—burned. That same year, and again in 2021, raging fires across Siberia sent a pall of smoke across the North Pole.
Massive wildfires in Australia gripped the world’s attention and affected more than 3 million animals, creating “one of the worst wildlife disasters in modern history.” And with the western United States in the grip of its worst drought for more than 1,200 years, a series of wildfires burned more than four million acres of California. The scientific evidence was unequivocal: More than half of the acres burned each year in the western United States can be attributed to climate change, with the number of dry, warm, and windy autumn days in California more than doubling since the 1980s.
Studies showed that the number of fires in the Sierra Nevada could increase by 20 percent or more by the 2040s, and that the total burned area could increase by about 25 percent or more—further evidence that the warning signs of global warming have not only increased over the last several decades, they are destined to do so even more in the future.