The amount of heat-trapping carbon dioxide in the atmosphere has exceeded a major milestone — more than 50% higher than pre-industrial times — and has not seen levels millions of years ago when Earth was an ocean-drenched planet, federal scientists announced Friday.
The National Oceanic and Atmospheric Administration said Her watch station for a long time In Mauna Loa, Hawaii, it averaged 421 parts per million of carbon dioxide for the month of May, which is the time when greenhouse gases reach their highest levels of the year. Scientists said that before the Industrial Revolution in the late 19th century carbon dioxide levels were 280 parts per million, so humans changed the atmosphere dramatically. Some activists and scientists want the 350 ppm level. Industrial carbon dioxide emissions come from burning coal, oil and gas.
Scientists say gas levels keep rising, when they need to be low. This year’s CO2 level is up about 1.9 parts per million from last year, a slightly bigger jump 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 right now in terms of change,” said NOAA climate scientist Peter Tans, who tracks the agency’s global greenhouse gas emissions.
Scientists from abroad said the numbers show a severe climate change problem.
“Humanity has to make a more serious effort and see a rapid decline in greenhouse gas emissions, or else the effects of climate change will continue to worsen,” said Jonathan Overbeck, dean of the environment at the University of Michigan.
Without cuts in carbon pollution, said University of Illinois climate scientist Donald Whipples, “we will see more devastating levels of climate change, more heat waves, more floods, more droughts, more big storms, and higher sea levels.”
The slowdown caused by the pandemic cut global carbon emissions slightly in 2020, but they rebounded last year. Both changes were small compared to the amount of carbon dioxide pumped into the atmosphere each year, especially considering that carbon dioxide stays in the atmosphere for as long as Hundreds to a thousand yearsTans said.
The world puts about 10 billion metric tons of carbon into the air each year, much of it being pulled up by oceans and plants. This is why May is the peak month for global carbon dioxide emissions. Plants in the northern hemisphere begin to absorb more carbon dioxide in the summer as they grow.
The National Oceanic and Atmospheric Administration (NOAA) said carbon dioxide levels are now about the same as 4.1 to 4.5 million years ago in the Pliocene, when temperatures were 7 degrees higher and sea levels were now 16 to 82 feet higher. South Florida, for example, was completely submerged. These are conditions that human civilization has not known.
The reason was so much It was warmer and the seas were higher millions of years ago At the same CO2 level as now, the natural increase in CO2 levels in the past has been more gradual. With carbon staying in the air for hundreds of years, temperatures rose over longer periods of time and stayed there. Tans and Overbeek said that the Antarctic and Greenland ice sheets have melted over time, dramatically raising sea levels, making Earth darker and reflecting less heat off the planet.
Scientists in Scripps Institution of Oceanography Levels calculated slightly differently based on time and average, setting the May average at 420.8 ppm, which is slightly below the NOAA number.