Scientists have warned that greenhouse gas emissions have reached an all-time high, and they also threaten to push the world into “unprecedented” levels of global heating.
From 2013 to 2022, “human-induced warming has been increasing at an unprecedented rate of over 0.2 degrees Celsius per decade,” researchers reported in a peer-reviewed study aimed at policymakers.
The world is rapidly running out of the “carbon budget”, this refers to the amount of carbon dioxide that can be poured into the atmosphere if we stay within the vital threshold of 1.5C above pre-industrial temperatures.
Only 250bn tonnes of carbon dioxide can now be emitted, down from 500bn tonnes just a few years ago.
At current annual rates of greenhouse gas emissions, of about 54bn tonnes a year, it would run out well before the end of this decade.
Prof Piers Forster, the director of the Priestley Centre for Climate Futures at the University of Leeds, and lead author of the paper said: “This is the critical decade for climate change. Decisions made now will have an impact on how much temperatures will rise and the degree and severity of impacts we will see as a result.”
He said the rate of annual increase in emissions had slowed down, but far more decisive action was needed. “We need to change policy and approaches in light of the latest evidence about the state of the climate system. Time is no longer on our side,” he said.
World leaders will be confronted with new data at the COP28 climate summit in Dubai, where a “Global Stocktake” will assess progress towards the 2015 Paris Agreement’s temperature goals. The findings would close the door on capping global warming under the 1.5C target, long identified as a guard rail for a climate-safe world.
The IPCC has calculated that to stay under the 1.5C threshold, emissions of carbon dioxide, methane, and other drivers of warming generated mainly through burning fossil fuels must not exceed 250 billion tons (Gt).
Keeping the Paris temperature targets in play would require slashing CO2 pollution by at least 40 percent by 2030 and eliminating it entirely by mid-century.
Unfortunately, one of the big climate success stories of the last decade has inadvertently hastened the pace of global warming.
A gradual drop in the use of coal has slowed the increase in carbon emissions. It has also reduced air pollution that shields Earth from the full force of the Sun’s rays.
Particle pollution from all sources dampens warming by about half-a-degree Celsius, meaning more heat will reach the planet’s surface as the air becomes cleaner.
- Piers M. Forster et al., ‘Indicators of Global Climate Change 2022: annual update of large-scale indicators of the state of the climate system and human influence’, Earth System Science Data, 8 June 2023, https://www.theguardian.com/environment/2023/jun/08/global-greenhouse-gas-emissions-at-all-time-high-study-finds