IIASA research shows that the remaining carbon budget to limit global warming to 1.5°C is significantly less than previously anticipated and could be depleted within the next six years.
The accurate assessment of anthropogenic CO2 emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is crucial for the assessment of future climate change impacts and the development of appropriate climate policies. The remaining carbon budget represents the net quantity of CO2 that can be emitted without overshooting a particular warming threshold.
Using updated methodologies and data published since the release of the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, a study conducted by IIASA researchers and colleagues from Imperial College London estimated that the remaining carbon budget is substantially lower than previously anticipated.
The study, published in Nature Climate Change, re-estimated the remaining carbon budget, and characterized some of the existing uncertainty. The results suggest that, as of January 2023, the remaining carbon budget for a 50% chance of keeping warming below 1.5°C is 250 gigatons of CO2 – significantly less than the number reported in the IPCC Sixth Assessment Report. This is due to the emissions that have been released since the publication of the IPCC report, as well as due to a change in the estimates of the cooling effect of aerosols on global temperatures.
The researchers suggest that at current global emissions levels of about 40 gigatons of CO2 per year, the remaining carbon budget to limit warming to 1.5°C may be exhausted within six years.
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