Scientists said Friday that the amount of global warming carbon dioxide in the atmosphere broke records in May and continued to rise. Before humans began widespread burning of oil, gas and coal in the late 19th century, it is now 50 percent higher than the pre-industrial average.
At least more carbon dioxide is present in the atmosphere than at any point in at least 4 million years, according to officials from the US National Oceanic and Atmospheric Administration.
As power plants, vehicles, farms and other sources around the world continued to emit large amounts of carbon dioxide into the atmosphere, gas concentrations reached about 421 ppm in May, peaking this year.Total emissions 36.3 billion tons in 2021The highest level in history.
As the amount of carbon dioxide increases, the planet continues to warm, with the effects of increased floods, extreme heat, droughts and the exacerbation of wildfires already experienced by millions of people around the world. Currently, the average temperature in the world is about 1.1 degrees Celsius and 2 degrees Fahrenheit, which is higher than before the Industrial Revolution.
Elevated carbon dioxide levels are evidence that countries have made little progress towards the goal set in Paris in 2015 to limit warming to 1.5 degrees Celsius. This is the threshold at which scientists say the potential for catastrophic effects of climate change is greatly increased.
“It clearly reminds us that we need to take urgent and serious steps to become a climate-responsive country,” NOAA administrator Rick Spinrad said in a statement. I am saying.
Carbon dioxide levels fell somewhat around 2020 during the coronavirus pandemic slowdown, but did not affect long-term trends, Pieter Tans, senior scientist at NOAA’s Global Monitoring Institute, said in an interview. rice field.
The rate of increase in carbon dioxide concentration “just continued,” he said. “And it’s progressing at about the same pace as in the last decade.”
Carbon dioxide levels change throughout the year, increasing as vegetation withers and rots in autumn and winter, and decreases as growing plants absorb gas by photosynthesis in spring and summer. It peaks in May each year, just before plant growth accelerates in the Northern Hemisphere. (North has a greater impact than the Southern Hemisphere because there is much more surface and vegetation in the north.)
Based on data from the NOAA Meteorological Observatory at the top of Mauna Loa volcano in Hawaii, Dr. Tans and colleagues at the institute calculated this year’s peak concentration to be 420.99 ppm. Observations began in the late 1950s by Charles David Keeling, a scientist at the Scripps Institution of Oceanography. The long-term record is known as the Keeling curve.
Scripps scientists are still observing in Mauna Loa under a program run by Dr. Keeling’s son, Ralph Keeling. Using independent data similar to NOAA, they calculated the concentration at 420.78.
Both numbers are about 2ppm higher than last year’s record. This peak is 140 ppm, consistently above the pre-industrial average concentration of about 280 ppm. Since then, humans have emitted about 1.6 trillion tons of carbon dioxide into the atmosphere.
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To reach the Paris Agreement target of 1.5 degrees Celsius, emissions must reach “net zero” by 2050. This means a sharp reduction, with the remaining emissions offset by the absorption of carbon dioxide by the ocean and vegetation. As the world approaches that goal, the rate of increase in carbon dioxide levels slows and the Keeling curve flattens.
If emissions are completely eliminated, the Keeling curve will begin to fall as the ocean and vegetation continue to absorb existing carbon dioxide from the air, Dr. Tans said. He said the decline in atmospheric concentrations will continue for hundreds of years, but will gradually slow down.
He said that equilibrium would be reached at some point, but carbon dioxide concentrations in both the atmosphere and the ocean would be higher than pre-industrial levels and would remain that way for thousands of years.
On such a long time scale, sea level can rise significantly due to melting polar ice and other changes such as the conversion of Arctic tundra to forests.
“What really matters to me is its long tail,” said Dr. Tans. “It can really change the climate.”