Seth Borenstein, Associated Press Published Friday, June 3, 2022, 2:47 PM EDT Last Updated on Friday, June 3, 2022, 2:47 PM EDT
The amount of heat-trapping carbon dioxide in the atmosphere has exceeded a key milestone – more than 50 percent higher than pre-industrial times – and is unprecedented millions of years ago when Earth was a greenhouse on an ocean-flooded planet, federal scientists said Friday.
The National Oceanic and Atmospheric Administration said its longtime monitoring station in Mauna Loa, Hawaii, averaged 421 parts per million carbon dioxide in May, when key greenhouse gas reached its annual peak. Before the industrial revolution in the late 19th century, carbon dioxide levels were 280 parts per million, scientists say, so people have changed the atmosphere significantly. Some activists and scientists want a level of 350 parts per million. Industrial carbon emissions come from the combustion of coal, oil and gas.
Gas levels continue to rise when they need to fall, scientists say. This year’s level of carbon dioxide is almost 1.9 ppm more than a year ago, a slightly larger jump than from May 2020 to May 2021.
“The world is trying to reduce emissions, and you just don’t see it. In other words, if you measure the atmosphere, you don’t see anything happening at the moment in terms of change, “said NOAA climatologist Peter Tans, who tracks global greenhouse gas emissions for the agency.
External scientists say the figures show a serious problem with climate change.
“Watching these growing but steady increases in CO2 from year to year is like watching a train tube down the rails to you in slow motion. It’s horrible, “said Andrea Dutton, a climatologist at the University of Wisconsin-Madison. “If we stay on the track with a plan to jump out of the way at the last minute, we could die from heat stroke on the slopes before it even reaches us.”
University of Illinois climatologist Donald Wubbles said that without reductions in carbon pollution, “we will see increasingly destructive levels of climate change, more heat waves, more floods, more droughts, more storms and higher sea levels.”
The slowdown in the pandemic did reduce global carbon emissions slightly in 2020, but they recovered last year. Both changes are small compared to how much carbon dioxide is pumped into the atmosphere each year, especially given that carbon dioxide stays in the atmosphere for hundreds to thousands of years, Tans said.
The world emits about 10 billion metric tons of carbon into the air each year, much of which is extracted from the oceans and plants. That is why it seems to be the peak of global carbon dioxide emissions. Plants in the northern hemisphere begin to absorb more carbon dioxide in the summer as they grow.
NOAA said carbon dioxide levels are now about the same as 4.1 to 4.5 million years ago in the Pliocene era, when temperatures were 7 degrees (3.9 degrees Celsius) hotter and sea levels was 16 to 82 feet (5 to 25 meters) taller than it is now. South Florida, for example, was completely underwater. These are conditions that human civilization has never known.
The reason it was much warmer and the seas were higher millions of years ago at the same level of carbon dioxide as it is now is that in the past the natural increase in carbon dioxide levels was much more gradual. Because carbon stays in the air for hundreds of years, temperatures heat up for longer periods of time and stay there. The ice sheets of Antarctica and Greenland have melted over time, raising sea levels tremendously and making the Earth darker and reflecting less heat than the planet, Tans and other scientists said.
Researchers at the Scripps Institute of Oceanography calculated the levels slightly differently based on time and averaging, and set the May average at 420.8 ppm, slightly lower than the NOAA figure.
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