IPCC report on Carbon budget

Carbon budget will exhaust in 10 years at current emission levels: IPCC report.

  • The world can emit approximately 400 billion tonnes more of carbon dioxide before hitting the 1.5°C limit.

  • The 16th Assessment Report (AR6) by the Intergovernmental Panel on Climate Change released 09 August 2021 has provided an updated estimate of the carbon budget the maximum amount of carbon dioxide (CO2) that can be emitted while still having a chance to limit warming to 1.5°C or 2°C.

  • The world can emit only about 500 giga tonnes of carbon dioxide (GtCO2) starting January 1, 2020 for a 50 per cent chance of limiting warming to 1.5°C. For a 67 per cent chance of avoiding 1.5°C, the budget will come down to 400 GtCO2.


The AR6 estimate of the remaining carbon budget from 2020 was developed on the basis of five components:


  • Historical warming till date.
  • Warming produced per tonne of CO2, also known as transient climate response to cumulative emissions of CO2 (TCRE); the AR6 says “each 1,000 GtCO2 of cumulative CO2 emissions is assessed to likely cause a 0.27°C to 0.63°C increase in global surface temperature with a best estimate of 0.45°C”
  • Warming that will occur once CO2 emissions reach net-zero levels, known as the zero emissions commitment (ZEC)
  • Warming from non-CO2 gases such as methane and nitrous oxide
  • Earth system feedbacks such as thawing of permafrost that would release additional carbon, and which were not considered in methodology earlier but are now added.

At least 40 countries in Europe, North America, Asia, Oceania and Africa have been hit by devastating disasters such as floods, storms, heat waves, wildfires and drought this year, and such extreme weather events are likely to be more frequent and severe.

Source: IPCC & DoE 

Topic GS-3: Environment, Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.