Global Courant
Global greenhouse gas emissions have hit an all-time high amid an unprecedented acceleration in global warming, according to a new study.
From 2013 to 2022, “human-induced warming has increased at an unprecedented rate of more than 0.2 degrees Celsius per decade,” 50 top scientists warned Thursday in a major climate science update.
Average annual emissions over the same period hit a record high of 54 billion tons of CO2 or its equivalent in other gases – about 1,700 tons per second – they reported in a peer-reviewed study aimed at policymakers.
World leaders will be confronted with the new data at the critical COP28 climate summit later this year in Dubai, where a “Global Stocktake” during United Nations talks will assess progress towards the temperature targets of the 2015 Paris Agreement .
The findings appear to close the door to hedging global warming under the more ambitious 1.5°C target of the Paris Agreement, which has long been seen as a guardrail to a relatively climate-secure world, albeit one that has yet to materialize. continues to be plagued by serious consequences.
“Even though we’re not at 1.5C of warming yet, the carbon budget” — the amount of greenhouse gases humanity can emit without exceeding that limit — “is likely to be exhausted within a few years,” said lead author Piers Forster, a physics researcher. professor at the University of Leeds.
That budget has shrunk by half since the UN’s climate science advisory body, the Intergovernmental Panel on Climate Change (IPCC), collected data for its most recent benchmark report in 2021, according to Forster and colleagues, many of whom were core contributors to the IPCC.
For even a chance to stay below the 1.5°C threshold, emissions of carbon dioxide, methane and other causes of warming, mainly caused by the burning of fossil fuels, must not exceed 250 billion tons ( gigatons), they reported.
Improving the odds to two-thirds or four-fifths would reduce those CO2 emissions to just 150 Gt and 100 Gt respectively, a two- or three-year lifeline at current emissions rates.
To keep the Paris temperature targets in play, CO2 pollution would need to be reduced by at least 40 percent by 2030 and completely eliminated by mid-century, the IPCC has calculated.
Ironically, one of the great climate success stories of the past decade has inadvertently accelerated the rate of global warming, the new data shows.
A gradual decline in the use of coal – significantly more carbon intensive than oil or gas – to produce power has slowed the increase in carbon emissions. But it has also reduced the air pollution that shields the Earth from the full force of the sun’s rays.
Particle pollution from all sources dampens warming by about half a degree Celsius, meaning that – at least in the short term – more of that heat will reach the Earth’s surface as the air gets cleaner.
The new study, published in the peer-reviewed journal Earth System Science Data, is the first in a series of periodic reviews that will help fill the gaps between IPCC reports, which have been released on average every six years since 1988.
“An annual update of key indicators of global change is critical to helping the international community and countries keep the urgency of tackling the climate change crisis at the top of their agenda,” said study co-author and scientist Maisa Rojas Corradi, who also is the Minister of the Environment of Chile.
Co-author Valerie Masson-Delmotte, 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 are indications that greenhouse gas increases have slowed. .
“The pace and scale of climate action are not enough to limit the escalation of climate-related risks,” she said.
Researchers also reported a surprising rise in temperature rises over land areas — excluding oceans — since 2000.
“Mean annual maximum temperatures on land have warmed by more than half a degree Celsius (1.72C above pre-industrial conditions) over the past decade compared to the first decade of the millennium (1.22C),” the study reported. .
Longer and more intense heat waves will pose a life-and-death threat in much of South and Southeast Asia over the coming decades, along with areas straddling the equator in Africa and Latin America, recent research has shown.
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