CO2 levels surge at unprecedented rate in 2024, pushing global climate goal at risk

A major global climate objective is in jeopardy as levels of the most important planet-warming gas in our atmosphere increased faster than ever before last year, according to scientists.

Carbon dioxide (CO2) concentrations have increased by over 50% since people began using fossil fuels extensively.

The natural environment was unable to absorb as much CO2 last year because of drought and wildfires, which led to record-high emissions from fossil fuels and more CO2 building up in the atmosphere.

The United Kingdom (UK) Met Office claims that the worldwide commitment to make efforts to keep global warming to 1.5C over pre-industrial levels is "incompatible" with the quick rise in CO2.

In order to prevent some of the worst effects of climate change, nearly 200 nations committed to this ambitious objective during a historic UN meeting in Paris in 2015.

The fact that 2024 was the hottest year on record and the first one with annual average temperatures more than 1.5 degrees Celsius above pre-industrial levels was confirmed last week.

The Paris Goal, which calls for a longer-term average across decades, was not broken by this, but sustained rises in atmospheric CO2 essentially condemn the globe to doing so.

"Limiting global warming to 1.5C would require the CO2 rise to be slowing, but in reality the opposite is happening," said Richard Betts, head of climate impacts research in the met office Hadley centre, UK.

Human activity—primarily the burning of coal, oil, and gas, as well as the clearing of forests—is to blame for the long-term rise in CO2.

According to the UN, CO2 levels are at their highest point in at least two million years, based on records of the Earth's climate from the distant past found in marine sediments and ice cores.

However, because of variations in how carbon is absorbed by the natural environment and variations in human emissions, the increase fluctuates from year to year.

According to early statistics from the Global Carbon Project team, CO2 emissions from fossil fuels hit all-time highs last year.

Additionally, the weather was impacted by the natural El Niño phenomena, which causes the surface waters of the eastern tropical Pacific Ocean to grow abnormally warm.

About half of human CO2 emissions have been absorbed by the natural world, such as increased plant growth and increased gas dissolution in the ocean.

However, last year's natural carbon sinks on land did not absorb as much CO2 as usual due to the additional heat blast from El Niño and climate change.

Additional CO2 was also emitted by widespread wildfires, even in areas that are not typically impacted by El Niño.

"Even without the boost from El Niño last year, the CO2 rise driven by fossil fuel burning and deforestation would now be outpacing the [UN climate body] IPCC's 1.5C scenarios," said Prof Betts.

Due to these reasons, CO2 levels rose by around 3.6 parts per million (ppm) of air molecules between 2023 and 2024, reaching a new high of over 424 ppm.

This is the highest annual increase since 1958, when atmospheric data were first recorded at the distant Mauna Loa research site in Hawaii.

Perched high on the edge of a volcano in the Pacific Ocean, the station's remote location, distant from major pollution sources, makes it ideal for monitoring global CO2 levels.

"These latest results further confirm that we are moving into uncharted territory faster than ever as the rise continues to accelerate," said Prof Ralph Keeling, who leads the measurement program at the Scripps Institution of Oceanography in the US.

The record rise heightens concerns that the environment may eventually lose its capacity to absorb chemicals that cause global warming.

According to the US science agency NOAA, warming and frequent fires are turning the Arctic tundra into a total source of CO2.

Drought, wildfires, and intentional deforestation are also affecting the Amazon rainforest's capacity to absorb CO2.

"It's an open question, but it's something we need to keep a close eye on and look at very carefully," Prof Betts said.

Although less drastic than in 2024, the Met Office projects that the rise in CO2 concentration in 2025 will still fall well short of the 1.5C target.

El Niño, which tends to allow the natural world to absorb more CO2, has been replaced by La Niña circumstances, where surface waters in the eastern tropical Pacific Ocean are cooler than usual.

"While there may be a temporary respite with slightly cooler temperatures, warming will resume because CO2 is still building up in the atmosphere," Prof Betts added.