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 EvidenceThe Keeling Curve tracks changes in the concentration of CO2 in the Earth’s atmosphere using data from a research station on Mauna Loa in Hawaii.Encyclopedia Britannica/UIG/Getty ImagesThe 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 TestifiesIn 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 C …
5 Key Moments That Forced Americans to Confront Climate Change – History
