A domestic research team announced findings that current carbon emissions exceed the limit the Earth can tolerate by more than double.
Professor Jeon Hae-won's team at the KAIST Graduate School of Green Growth and Sustainability said on the 6th that, through joint research with Paul Wolfram's team at the Pacific Northwest National Laboratory (PNNL) under the U.S. Department of Energy, they recalculated the carbon dioxide emission limit. The results were published in the international journal "Nature Sustainability" on Feb. 16 (local time).
Until now, climate change has been assessed based on how much carbon dioxide has accumulated in the atmosphere (stock position). In contrast, nitrogen and phosphorus pollution have been calculated based on how much is emitted per year (flow). Because different yardsticks were used, it was difficult to fairly compare which problem is more serious.
The researchers recalculated carbon using the same annual emissions metric as nitrogen. An analysis aligned with the condition of limiting the global average temperature rise to within 1.5 degrees found that the Earth's annual carbon dioxide emission limit it can tolerate is about 4–17 Gt (gigatons). But humanity's current annual emissions are about 37 Gt. This exceeds the Earth's safe operating space by more than double.
Jeon Hae-won said, "When comparing carbon emissions using the same metric as nitrogen pollution, the severity of climate change becomes much clearer," adding, "This study will help set policy priorities more clearly by allowing different environmental problems to be viewed on the same basis."
Jeon added, "The need to establish an integrated strategy that considers carbon alongside nitrogen and phosphorus pollution is growing," and emphasized, "We must further accelerate global decarbonization efforts."
References
Nature Sustainability (2026), DOI: https://doi.org/10.1038/s41893-026-01770-6