Scientists warn of unprecedented increase in global warming at over 0.2 degrees Celsius per decade

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8th January 2023 – (Leeds) A group of 50 top scientists has issued a stark warning about the acceleration of global warming due to record-high greenhouse gas emissions and diminishing air pollution. In a sweeping climate science update, they reported that from 2013 to 2022, human-induced warming has been increasing at an unprecedented rate of over 0.2 degrees Celsius per decade. The report was peer-reviewed and aimed at policymakers.

The study found that average annual emissions over the same period hit an all-time high of 54 billion tonnes of CO2 or its equivalent in other gases, which equates to about 1,700 tonnes every second. These findings will be presented to world leaders at the critical COP28 climate summit later this year in Dubai, where a “Global Stocktake” at the UN talks will assess progress towards the 2015 Paris Agreement‘s temperature goals.

The data would appear to close the door on capping global warming under the Paris treaty’s more ambitious 1.5 degrees Celsius target, which has long been identified as a guard rail for a relatively climate-safe world, albeit one still roiled by severe impacts. Lead author Piers Forster, a physics professor at the University of Leeds, warned that even though the world has not yet reached 1.5C warming, “the carbon budget” – the amount of greenhouse gases humanity can emit without exceeding that limit – “will likely be exhausted in only a few years.”

The carbon budget has shrunk by half since the UN’s climate science advisory body, the Intergovernmental Panel on Climate Change (IPCC), gathered data for its most recent benchmark report in 2021, according to Forster and colleagues, many of whom were core IPCC contributors. To have even a coin-toss chance of staying under the 1.5 degrees Celsius threshold, emissions of carbon dioxide, methane, and other drivers of warming generated mostly by burning fossil fuels must not exceed 250 billion tonnes (Gt), they reported.

For a two-thirds or four-fifths chance of staying under the 1.5 degrees Celsius threshold, the carbon allowance would reduce to only 150 Gt and 100 Gt, respectively, which would provide a two- or three-year lifeline at the current rate of emissions. The IPCC has calculated that keeping the Paris temperature targets in play would require slashing CO2 pollution by at least 40% by 2030 and eliminating it entirely by mid-century.

The new data also revealed an unintended consequence of the gradual drop in the use of coal – significantly more carbon-intensive than oil or gas – to produce power, which has inadvertently hastened the pace of global warming. While reducing carbon emissions, it has also reduced the 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, which means – at least in the short term – more of that heat will reach the planet’s surface as the air becomes cleaner.

The new study, published in the peer-reviewed journal Earth System Science Data, is the first in a series of periodic assessments that will help fill the gaps between IPCC reports, released on average every six years since 1988. Co-author Valerie Masson-Delmotte, a co-chair of the 2021 IPCC report, said the new data should be a “wake-up call” ahead of the COP28 summit, even if there is evidence that the increase in greenhouse gases has slowed.

The report also revealed a startling rise in temperature increases over land areas, excluding oceans, since 2000. The study reported that land average annual maximum temperatures have warmed by more than half a degree Celsius in the last ten years (1.72C above preindustrial conditions) compared to the first decade of the millennium (1.22C). Recent research has shown that longer and more intense heat waves will pose a life-and-death threat in the coming decades across large swathes of South and Southeast Asia, along with areas straddling the equator in Africa and Latin America.