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Stop burning fossil fuels: Stay within the IPCC carbon budget of 420Gt CO2

  • The IPCC SR15 report of October 2018 gave 420 billion tonnes (420Gt) as the maximum amount of CO2 that can be emittted globally without a major risk of devastating consequences [1]. To be precise, this is 420Gt from 1 Jan 2018.

  • The global population emitted another 34Gt of CO2 in 2018, leaving a budget of 386Gt from 1 Jan 2019 (420 - 34 is 386).

  • With a world population of 7.7 billion, this 386 billion tonnes of CO2 is 50 tonnes per person when shared equally.

  • The UK CO2 emissions are around 10 tonnes per person per year [2]. The UK took little action during 2019, and so will emit another 10 tonnes per person in 2019 - so we have just used one fifth of our remaining CO2 budget, and now have 40 tonnes per person left from 1 Jan 2020.

  • To stay within this budget, we now need to make radical reductions in emissions (as explained by the IPCC[3]). Some simple maths tells us that reducing the UK average by 20% per year as an exponential decline will achieve this - see chart.


[1] IPCC SR15 Report p108 (p16 of chapter 2)

First published: Dec 2019
Last updated: 9 Feb 2020