People walk through a cooling mist sprayer in Las Vegas on June 4, 2024. Tens of millions of people from California to Texas are experiencing extreme heat as new data shows the amount of global-warming carbon dioxide in the atmosphere hits a new record.
John Rocker/AP
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John Rocker/AP
The amount of planet-warming carbon dioxide in the Earth’s atmosphere has reached a new record as humanity struggles to curb greenhouse gas emissions from burning fossil fuels.
The new record comes as tens of millions of people in the United States are suffering extreme weather. Much of the Western U.S. is experiencing the first major heat wave of the year, with temperatures 20 to 30 degrees Fahrenheit above normal for June. In the Southwest, temperatures have continued to reach well above 100 degrees Fahrenheit.
Scientists say these extreme and prolonged heat waves are directly linked to human-induced climate change: Excess carbon dioxide (CO2) in the atmosphere traps heat, leading to more intense, frequent and persistent heatwaves and extreme weather events like powerful hurricanes and torrential rainstorms.
“Over the past year, we’ve experienced the hottest year on record, the warmest ocean temperatures on record, and endless heat waves, droughts, floods, wildfires and storms,” National Oceanic and Atmospheric Administration (NOAA) Administrator Rick Spinrad said in a statement. “These are clear signs of the damage that carbon pollution is doing to our climate system and we must take immediate action to reduce our fossil fuel use as quickly as possible.”
Atmospheric carbon dioxide concentrations are measured in parts per million and are measured at an observatory in Hawaii. Atmospheric carbon dioxide concentrations peak in May because more carbon dioxide gas accumulates during the winter months when there are fewer leaves around the world to absorb the carbon dioxide.
In May, atmospheric carbon dioxide levels hit nearly 427 parts per million, an increase of about 3 parts per million from last year’s peak, one of the largest annual increases on record, scientists say.
Most of the global warming pollutants in the atmosphere come from humans burning fossil fuels such as oil, gas and coal.
The amount of carbon dioxide in the atmosphere has been steadily increasing since scientists began making regular measurements in 1958. At that time, atmospheric CO2 levels were 313 parts per million, slightly higher than in the 19th century, when the Industrial Revolution led to widespread fossil fuel consumption.
But the increase in atmospheric carbon dioxide has accelerated in recent years: Carbon dioxide levels have increased more rapidly in the first four months of this year than they have in the first four months of any previous year, according to scientists at NOAA and the Scripps Institution of Oceanography at the University of San Diego.
Routine direct measurements of atmospheric carbon dioxide began in the 1950s, but scientists can use other methods to estimate how much carbon dioxide was in the atmosphere going back millions of years — and there is more carbon dioxide today than there was in those millions of years.
The rising carbon dioxide levels highlight that humanity’s collective efforts to cut greenhouse gas emissions and switch to renewable energy sources are falling short of what’s needed to limit rising global temperatures. While U.S. greenhouse gas emissions fell slightly last year, the decline doesn’t put the country on track to meet the climate goals set by the Biden administration.
