【】

The pandemic couldn't thwart the relentlessly rising carbon dioxide in Earth's atmosphere.

Scripps Institution of Oceanography, which collects daily measurements of atmospheric CO2 atop Hawaii's Mauna Loa, announced Thursday that CO2 levels reached a record high in May 2020 (atmospheric CO2 hits its annual high point each May). The research institute measured an average of just over 417 parts per million, or ppm, last month, likely the highest amount in millions of years. This new record was expected: CO2 levels have been accelerating in the atmosphere since 1958, when record-keeping began at the Mauna Loa Observatory.

As the Scripps chart below depicts, atmospheric CO2 was around 317 ppm in the late 1950s. This May, it hit 417.2 ppm.

(You’ll notice the saw-like line going upward in the chart. This "saw" appearance shows how each year atmospheric CO2 levels also naturally rise and fall when the great forests of the Northern Hemisphere gulp up CO2 during the spring, and then decomposed leaves release it back into the atmosphere during the fall and winter. May is the "turning point," when atmospheric CO2 reaches its annual apex and then starts to temporarily decline as hundreds of millions of trees suck up CO2.)

Atmospheric CO2 hit a record high in 2020.Credit: Scripps Institution of Oceanography

Though global carbon emissions plummeted in April 2020 (by 17 percent compared to 2019) due to wide-scale societal shutdowns intended to curb the spread of the new coronavirus, there was still a profound amount of CO2 being emitted into the air — just not as much as there would have been without a historic pandemic.

Atmospheric CO2 levels are like a massive bank account that’s been accruing more and more carbon every year for well over a century (this bank account is now at its highest levels in at least800,000 years, but more likely millions of years). This year’s carbon emissions, however, are just a deposit. So the 2020 deposit may be smaller than in 2019, but it’ll still add to the burgeoning bank account, or "pile" of atmospheric CO2.

"The pile is still there," Ralph Keeling, the director of the Scripps CO2 Program at the Scripps Institution of Oceanography, told Mashable in March. "We're not getting rid of the pile [with temporary shutdowns]."

Mashable Light SpeedWant more out-of-this world tech, space and science stories?Sign up for Mashable's weekly Light Speed newsletter.By signing up you agree to our Terms of Use and Privacy Policy.Thanks for signing up!

To significantly slow the relentless upward atmospheric CO2 trajectory, unprecedented emissions reductions of 20 to 30 percent would have to be sustained for six to 12 months, Scripps noted.

Overall, it’s fair to say that atmospheric CO2 is now skyrocketing, as fossil fuels are currently the dominant source of energy on Earth. In the 1970s, around the first Earth Day, CO2 levels were going up by about 1 ppm per year. But the rate has increased to, on average, 2.4 ppm over the last decade.

In May 2019, CO2 averaged 414.8 ppm, making this year’s average about 2.4 ppm higher.

"The rate of CO2 increase since the first Earth Day is unprecedented in the geologic record," Dan Breecker, a paleoclimatologist at The University of Texas at Austin, told Mashable last year.

We've got skyrocketing carbon emissions.Credit: SCRIPPS INSTITUTION OF OCEANOGRAPHY

The reason why is clear. 

"There is abundant and conclusive evidence" that the acceleration is caused by increased [carbon] emissions, Pieter Tans, a senior scientist with NOAA’s Global Monitoring Laboratory, said in the Scripps press release.

The planet continues to react to rising concentrations of CO2 in the air. CO2 is a potent heat-trapping greenhouse gas, which can live in the atmosphere for 300 to 1,000 years. This means the decisions we make today about how we power our homes, cars, and lives will make a critical difference in how much Earth will warm in the future. Already, 19 of the last 20 years are now the warmest on record.

"Thus, as humans change the atmosphere by emitting carbon dioxide, those changes will endure on the timescale of many human lives," writes NASA

(责任编辑：熱點)