Record Rise in CO2 Concentrations in Atmosphere Puts World Off Track For 1.5C Warming Goal: Met Office

Atmospheric CO2 concentrations are now 51% higher than before the onset of the Industrial Revolution.

—

A record year-on-year growth of concentrations of carbon dioxide (CO2) in the atmosphere last year has put the world off track to keep global warming below the key 1.5C target, the UK’s Met Office said last week.

CO2 concentrations rose 3.58 parts per million (ppm) in 2024, far exceeding the weather forecaster’s prediction. The record rise is inconsistent with the 1.8ppm annual increase the Intergovernmental Panel on Climate Change (IPCC) – the world’s most authoritative – said is needed to limit warming below the goal set out by countries in the 2015 Paris Agreement.

The substantial increase is mostly due to record high emissions from fossil fuel combustion, weaker carbon sinks – particularly in tropical forests – and an exceptionally active wildfire season throughout 2024, the forecasters said. Destructive wildfires were triggered by widespread hot and dry conditions, influenced partly by the return of the El Niño weather pattern and other factors, including the effects of climate change.

More on the topic: Destructive Wildfires At Least Three Times More Likely Due to Climate Change, Report Finds

Global CO2 emissions from fossil fuels have increased by more than 60% since 1990, currently standing at 425.40 ppm. Atmospheric concentrations are now 51% higher than they were before the onset of the Industrial Revolution.

Carbon dioxide, a by-product of burning fossil fuels, biomass, land-use changes, and industrial processes such as cement production, is the principal anthropogenic greenhouse gas in the atmosphere, responsible for about three-quarters of planet-warming emissions, followed by methane and nitrous oxide. 

Methane – a gas mainly associated with fossil fuel use, agriculture and waste – is responsible for 25% of global warming. It is 84 times more potent in trapping heat in the atmosphere than CO2 over a two-decade period and it possesses a 100-year global warming potential 28-34 times that of CO2. Global methane emissions have been on the rise and atmospheric concentrations of the potent gas are now more than 165% higher than pre-industrial levels in 1750.

Nitrous oxide is the third-most significant human-caused greenhouse gas, mainly associated with the use of nitrogen fertilizer and manure from the expansion and intensification of agriculture. Atmospheric concentrations of this gas are now 25% higher than the pre-industrial level of 270 parts per billion.

Off Track

Last year, the World Meteorological Organization warned that the world is “more likely than not” to surpass the critical global warming threshold by 2027, while the UN Environment Programme said current emissions reduction pledges put us on track for a temperature increase of 2.6-3.1C over the course of this century. A survey of 380 IPCC scientists conducted by the Guardian last May also revealed that 77% of them believe humanity is headed for at least 2.5C of warming.

Last year, the hottest year on record, also marked the first calendar year that the average global temperature exceeded 1.5C above its pre-industrial level. While this does not signal a permanent breach of the critical limit, which scientists say is measured over decades, it sends a clear warning to humanity that we are approaching the point of no return much faster than expected.

The Earth has already warmed 1.3C. According to scientists, every fraction of a degree of warming matters, with every additional increment of global warming causing “clearly discernible increases in the intensity and frequency of temperature and precipitation extremes, as well as agricultural and ecological droughts in some regions.”