The federal government’s decision last week to stop regulating greenhouse gas emissions is personal to scientists in San Diego.
That’s because one of the scientific cornerstones of that federal policy, the endangerment finding, is rooted in local research that dates back to 1958.
It’s called the Keeling Curve. Most people may have never heard of it, but it has played a vital role in tracking the impact of human activity on the Earth.
“The Keeling Curve was really the first clear evidence of human impacts at that scale of the global climate,” said Ralph Keeling, a geochemist at Scripps Institution of Oceanography and director of the Scripps CO2 Program.
His late father, Charles David Keeling, founded the program in 1956 and oversaw it until he died in 2005.
“For decades here, starting with my father, we’ve been tracking the buildup of carbon dioxide in the atmosphere through measurements around the world. But most notably in Hawaii on Mauna Loa,” said Keeling.
Before him, measurements were inconsistent, but Charles Keeling is credited with recording the longest and most precise continuous measurements of carbon dioxide, starting in 1958 from Hawaii’s Mauna Loa Observatory. The process involved capturing air samples using glass spherical flasks and analyzing them in the lab to determine the amount of carbon dioxide present in those samples.
To this day, the measurements show a steady, rising curve with a wavy line layered on top. The highs and lows of that wave represent the Earth’s breath. It inhales as plants grow during spring and summer, and exhales as vegetation dries out during fall and winter.
“(The Keeling Curve) is also the pulse of the planet,” said Ralph Keeling. “We’re seeing what’s going on.”
Not only has the curve shown that carbon dioxide levels are consistently increasing, but it also indicates that human activity, such as burning fossil fuels, is accelerating the decades-long trend.
According to its latest measurements, levels jumped from 315 parts per million in 1958 to more than 420 parts per million today.
Because the Keeling Curve has been one of the most important data sets on global climate change, Ralph Keeling said it was influential in the government’s eventual determination that greenhouse gas emissions are harmful and must be regulated.
“It certainly played a role in setting in motion the whole process of thinking about climate change, understanding the impacts of rising CO2, eventually building a consensus that something needed to be done about it,” he said. “So, it was really at the foundation of all of that. And of course, it started right here in San Diego.”
Without the endangerment finding, the federal government has essentially removed its obligation to do something about greenhouse gas emissions.
That’s something Ralph Keeling worries about.
“CO2 is not going down, CO2 is going up,” he said. “It's going up faster than ever."
Last week, Lee Zeldin, the Environmental Protection Agency’s administrator, said the endangerment finding had led to too much red tape for automakers.
“Manufacturers will no longer be burdened by measuring, compiling, or reporting greenhouse gas emissions for vehicles and engines, and the forced transition to electric vehicles is eliminated,” he said.
The EPA has argued that the Clean Air Act, which requires the agency to regulate pollutants deemed harmful to the public, is meant to regulate pollutants that linger in the air people breathe, like smog. It doesn’t give the EPA the authority to regulate greenhouse gases that remain in the atmosphere, the administration said.
Keeling argued that it doesn’t change the fact that greenhouse gases create health harms and worsen the severity and frequency of wildfires, sea-level rise, flooding and heatwaves.
“Just because something doesn't immediately kill you doesn't mean it's (not) a pollutant,” he said. “It can mess up the systems around you that affect your health and welfare.”
Last year, environmental and science groups filed lawsuits against the EPA, challenging its first steps to rescind the endangerment finding. The state of California and environmental groups, including the Sierra Club, are vowing to go to court, following last week’s move.
