The amount of heat-trapping carbon dioxide in the atmosphere has shot past a key milestone -- more than 50% higher than pre-industrial times -- and is at levels not seen since millions of years ago when Earth was a hothouse ocean-inundated planet, federal scientists announced Friday. The National Oceanic and Atmospheric Administration said its long-time monitoring station at Mauna Loa, Hawaii, averaged 421 parts per million of carbon dioxide for the month of May, which is when the crucial greenhouse gas hits its yearly high. Before the industrial revolution in the late 19th century carbon dioxide levels were at 280 parts per million, scientists said, so humans have significantly changed the atmosphere. Some activists and scientists want a level of 350 parts per million. Industrial carbon dioxide emissions come from the burning of coal, oil and gas. Levels of the gas continue to rise, when they need to be falling, scientists say. This year’s carbon dioxide level is nearly 1.9 ppm more than a year ago, a slightly bigger 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’re measuring the atmosphere, you’re not seeing anything happening right now in terms of change,” said NOAA climate scientist Pieter Tans, who tracks global greenhouse gas emissions for the agency. Outside scientists said the numbers show a severe climate change problem. Also read: WHO for making mental health support part of climate action plans “Watching these incremental but persistent increases in CO2 year-to-year is much like watching a train barrel down the track towards you in slow motion. It’s terrifying,” said University of Wisconsin-Madison climate scientist Andrea Dutton. “If we stay on the track with a plan to jump out of the way at the last minute, we may die of heat stroke out on the tracks before it even gets to us.” University of Illinois climate scientist Donald Wuebbles said without cuts in carbon pollution “we will see ever more damaging levels of climate change, more heat waves, more flooding, more droughts, more large storms and higher sea levels.” The slowdown from the pandemic did cut global carbon emissions a bit in 2020, but they rebounded last year. Both changes were small compared to how much carbon dioxide is pumped into the atmosphere each year, especially considering that carbon dioxide stays in the atmosphere hundreds to a thousand years, Tans said. The world puts about 10 billion metric tons of carbon in the air each year, much of it gets drawn down by oceans and plants. That’s why May is the peak for global carbon dioxide emissions. Plants in the northern hemisphere start sucking up 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 were 16 to 82 feet (5 to 25 meters) higher than now. South Florida, for example, was completely under water. These are conditions that human civilization has never known. The reason it was much warmer and seas were higher millions of years ago at the same carbon dioxide level as now is that in the past the natural increase in carbon dioxide levels was far more gradual. With carbon sticking in the air hundreds of years, temperatures heated up over longer periods of time and stayed there. The Antarctic and Greenland ice sheets melted over time, raising sea levels tremendously and making Earth darker and reflecting less heat off the planet, Tans and other scientists said. Scientists at the Scripps Institution of Oceanography calculated levels a bit differently based on time and averaging, and put the May average at 420.8 ppm, slightly lower than NOAA’s figure.  

The annual peak of global heat-trapping carbon dioxide in the air has reached another dangerous milestone: 50% higher than when the industrial age began. And the average rate of increase is faster than ever, scientists reported Monday. The National Oceanic and Atmospheric Administration said the average carbon dioxide level for May was 419.13 parts per million. That’s 1.82 parts per million higher than May 2020 and 50% higher than the stable pre-industrial levels of 280 parts per million, said NOAA climate scientist Pieter Tans. Carbon dioxide levels peak every May just before plant life in the Northern Hemisphere blossoms, sucking some of that carbon out of the atmosphere and into flowers, leaves, seeds and stems. The reprieve is temporary, though, because emissions of carbon dioxide from burning coal, oil and natural gas for transportation and electricity far exceed what plants can take in, pushing greenhouse gas levels to new records every year. Also read: Climate change accelerates during 2015-2019: WMO “Reaching 50% higher carbon dioxide than preindustrial is really setting a new benchmark and not in a good way,” said Cornell University climate scientist Natalie Mahowald, who wasn’t part of the research. “If we want to avoid the worst consequences of climate change, we need to work much harder to cut carbon dioxide emissions and right away.” Climate change does more than increase temperatures. It makes extreme weather — storms, wildfires, floods and droughts — worse and more frequent and causes oceans to rise and get more acidic, studies show. There are also health effects, including heat deaths and increased pollen. In 2015, countries signed the Paris agreement to try to keep climate change to below what’s considered dangerous levels. Also read: Next 10 years final chance to avert climate catastrophe: UN chief The one-year jump in carbon dioxide was not a record, mainly because of a La Nina weather pattern, when parts of the Pacific temporarily cool, said Scripps Institution of Oceanography geochemist Ralph Keeling. Keeling’s father started the monitoring of carbon dioxide on top of the Hawaiian mountain Mauna Loa in 1958, and he has continued the work of charting the now famous Keeling Curve. Scripps, which calculates the numbers slightly differently based on time and averaging, said the peak in May was 418.9. Also, pandemic lockdowns slowed transportation, travel and other activity by about 7%, earlier studies show. But that was too small to make a significant difference. Carbon dioxide can stay in the air for 1,000 years or more, so year-to-year changes in emissions don’t register much. The 10-year average rate of increase also set a record, now up to 2.4 parts per million per year. “Carbon dioxide going up in a few decades like that is extremely unusual,” Tans said. “For example, when the Earth climbed out of the last ice age, carbon dioxide increased by about 80 parts per million and it took the Earth system, the natural system, 6,000 years. We have a much larger increase in the last few decades.” By comparison, it has taken only 42 years, from 1979 to 2021, to increase carbon dioxide by that same amount. “The world is approaching the point where exceeding the Paris targets and entering a climate danger zone becomes almost inevitable,” said Princeton University climate scientist Michael Oppenheimer, who wasn’t part of the research.

Global energy-related carbon dioxide emissions rose slightly in December compared with the same month of 2019, indicating the sharp drop seen due to the pandemic was short-lived.

 A new study warns that rising temperatures driven by climate change could cause millions of deaths per year by the end of the century.