Every year, researchers at the Global Carbon Project analyse the global carbon cycle. Both human-caused emissions and emissions and uptake from natural sources are included. Researchers from the CICERO Center for International Climate Research participate in this work.
The project began in 2001. Despite the fact that countries around the world largely agree that greenhouse gas emissions must be reduced, global emissions have mostly increased year after year, apart from some temporary declines during the financial crisis and the Covid-19 pandemic.
In 2025, the world’s total CO2 emissions reached a record high. This year, researchers expect a slight decline. Will it last?
"Unfortunately, this is not due to structural changes and climate measures," says Kjetil Aas.
He is a a climate researcher at CICERO.
"That's part of the picture, but the main reason emissions are expected to fall this year is the closure of the Strait of Hormuz, which led to higher prices and reduced access to fossil energy, particularly oil and gas," says Aas, who contributed to the report.
Researchers estimate that solar and wind power now meet about two-thirds of the world's increased energy demand.
"This has visibly slowed the increase in CO2 emissions, but we would not have seen a decline this year if it had not been for the crisis in the oil market," he says.
If fossil fuel prices fall again, emissions could rise again next year.
"But because this is a crisis that directly affects the energy market, it's reasonable to think that it could accelerate the transition in some countries," says Aas.
The motivation to phase out fossil fuels could increase when they are perceived as a less reliable energy source than before, he believes.
The trend in global emissions.(Graph: Global Carbon Project)
Will exceed 1.5 degrees
The concentration of CO2 in the atmosphere will reach 427.7 ppm in 2026, which is 54 per cent above pre-industrial levels, according to the report.
There is very little room left in the carbon budget if global warming is to be limited to 1.5 degrees.
At current emission levels, that budget could be exhausted in less than four years.
"The 1.5-degree target now seems completely unrealistic, at least if the aim is to remain below that threshold without temporarily exceeding it," says Aas.
In the longer term, it may be possible to bring temperatures back down if emissions first reach net zero and then become negative.
Annonse
"But it's now absolutely clear that we will exceed 1.5 degrees, at least temporarily," the researcher says.
Slight decline in China
China, which accounts for approximately 32 per cent of global greenhouse gas emissions, is expected to see a slight decline of 0.9 per cent this year.
This follows several years of relatively stable emissions and a major expansion of renewable energy. Many have suggested that emissions may soon start to decline.
"China has seen a noticeable decline this year. The major question is whether this marks the peak in its emissions," says Aas.
At the same time, China has also been affected by the crisis in the oil market, so it is still a little too early to say whether the decline represents a lasting trend, according to Aas.
Annual CO2 emissions by region.(Graph: Global Carbon Project)
In the United States, emissions are expected to fall by 1.3 per cent this year.
"The United States has experienced a fairly long-term downward trend. This is due to a structural shift away from coal, the worst energy source when it comes to CO2 emissions," says Aas.
Although emissions associated with natural gas have increased, the overall shift in the American energy system has contributed to lower CO2 emissions over the past two decades, the researcher explains.
"We are seeing some decline in oil consumption this year, which can probably be partly attributed to the disruption caused by the closure of the Strait of Hormuz," he says.
EU countries account for 6 per cent of global emissions and continue to make reductions. Emissions are expected to fall by 1.5 per cent this year.
"In Europe, deliberate climate and energy policies have played a greater role in driving the downward trend than in the United States. But the EU is also being affected by what's happening in the global energy market," he says.
Will nature continue absorbing as much carbon?
Kjetil Aas works on the part of the carbon accounting that deals with nature's capacity to absorb carbon – how vegetation on land responds to climate change and increased CO2 in the atmosphere.
"We are beginning to see that a warmer climate inhibits CO2 uptake, especially in the tropics," says Aas.
Around half of our emissions are absorbed by the oceans and on land, while the rest remain in the atmosphere.
"This has been fairly stable over a long period, although uptake on land varies more with weather conditions from year to year," he says.
In 2023 and 2024, there was a fairly strong El Niño. Researchers then saw that carbon uptake on land declined.
"We began to worry that this might indicate a lasting decline in vegetation's capacity to absorb carbon. Based on last year's figures and estimates for 2026, it seems that the land has recovered more than we feared," the researcher says.
This year, however, an exceptionally strong El Niño has taken hold. This is making large parts of the Amazon drier.
"We won't see the effect until next year. The fact that vegetation recovered for one year is not enough to declare it healthy and say that everything is fine. This will be particularly important to monitor going forward," he says.
One encouraging development is the reduction in CO2 emissions associated with land-use changes, such as deforestation.
Over the past decade, total emissions from fossil fuels and lang-use changes combined have increased by an average of 0.3 per cent per year, compared with 1.7 per cent in the previous decade.
"There has been a decline in deforestation. This year, emissions appear to be somewhat higher, but the estimates are highly uncertain. We therefore need to be careful about drawing conclusions from individual years," Aas says, adding:
"In some regions, forests are expanding faster than they're being cut down. Europe has long been an example of this. We also see it in China. But there are some countries in the tropics that account for large emissions."
54 per cent of emissions from land-use changes come from deforestation in Brazil, Indonesia, and the Congo.
"The first milestone"
Aas concludes by saying that the researchers wish total emissions were declining this year for reasons other than war.
"There is still more work to be done before we reach the peak. The peak is the first milestone we need to reach, but the major task is to bring emissions down towards zero or compensate by removing CO2 from the atmosphere," says Kjetil Aas.
