Global average temperature rise should not exceed 1.5°C if catastrophic climate change is to be avoided, the Intergovernmental Panel on Climate Change (IPCC) says.
To meet this goal, IPCC has set a limit on how much carbon the world can emit in the future. This limit is called the carbon budget or the emissions budget.
In 2014, the IPCC had estimated that the carbon budget was 2,900 Gigatonnes (GT). This carbon budget was from pre-industrial times to the end of the 21st century.
But by 2017, the world had already emitted 2,200 GT or about three-fourths of this budget. To avoid breaching the 1.5°C mark, the world can emit only 420-570 GT till century-end.
Historically, the US and the EU (28) usurped most this carbon budget. Americans, some 4.3 per cent of the world population, caused 25% of historical emissions (1751-2017). The EU, which consists of 6.8 per cent of the world population, caused 22 per cent of the emissions (1751-2017).
However, India, which houses nearly 18 per cent of the world population, had emitted only 3 per cent. Carbon budget is not the same as greenhouse gas (GHG) budget. Fossil CO2 was responsible for 68% of all emissions in 2018
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