In a comprehensive climate science update released on Thursday, 50 leading scientists cautioned that historically high greenhouse gas emissions and declining air pollution had triggered an unmatched acceleration of global warming.
In a peer-reviewed paper geared at policymakers, they stated that from 2013 through 2022, “human-induced warming has been increasing at an unprecedented rate of over 0.2 degrees Celsius per decade.”
Over the same time period, average annual emissions reached a record 54 billion tonnes of CO2 or its equivalent in other gases, or about 1,700 tonnes per second.
At the crucial COP28 climate summit later this year in Dubai, when a “Global Stocktake” at the UN talks will evaluate progress towards the 2015 Paris Agreement’s temperature goals, world leaders will be confronted with the new statistics.
The findings would seem to rule out limiting global warming under the Paris Treaty’s more aggressive 1.5C target, which has long been regarded as a safety net for a world that is mostly climate-safe, although still being rocked by severe consequences.
The quantity of greenhouse gases that humans can produce without going over that threshold, or the “carbon budget,” “will likely be exhausted in only a few years,” according to lead author Piers Forster, a physics professor at the University of Leeds.
According to Forster and colleagues, many of whom were core IPCC contributors, that budget has decreased by half since the Intergovernmental Panel on Climate Change (IPCC), the UN organisation that advises on climate science, gathered information for its most recent benchmark report in 2021.
They concluded that emissions of carbon dioxide, methane, and other warming agents, which are mostly produced by burning fossil fuels, must not surpass 250 billion tonnes (Gt) in order to have even a coin-toss chance of staying below the 1.5C threshold.
A two- or three-year lifeline at the current rate of emissions would be provided by cutting that carbon allowance to only 150 Gt or 100 Gt, respectively, by increasing the odds to two-thirds or four-fifths.
According to the IPCC, in order to maintain the Paris temperature targets, CO2 emissions must be reduced by at least 40% by 2030 and completely eliminated by the middle of the century.
The new data show that, ironically, one of the major climate success stories of the past ten years has unintentionally accelerated the rate of global warming.
The usage of coal, which emits substantially more carbon dioxide per unit of energy produced than either oil or gas, has gradually decreased.
However, it has also lessened air pollution, which protects Earth from the Sun’s rays at their full intensity.
Particle pollution from all sources dampens warming by around half a degree Celsius, so as the air gets cleaner, more heat will eventually reach the planet’s surface.
The new analysis, the first in a series of periodic evaluations that will help bridge the gaps between IPCC reports, which have been published on average every six years since 1988, was published in the peer-reviewed journal Earth System Science Data.
“An annual update of key indicators of global change is critical in helping the international community and countries to keep the urgency of addressing the climate change crisis at the top of the agenda,” said co-author and scientist Maisa Rojas Corradi, who is also Chile’s environment minister.
Even if there is evidence that the increase in greenhouse gases has moderated, co-author Valerie Masson-Delmotte, a co-chair of the 2021 IPCC assessment, said the new data should be a “wake-up call” before the COP28 session.
“The pace and scale of climate action is not sufficient to limit the escalation of climate-related risks,” she claimed.
Apart from oceans, researchers also noted a remarkable surge in temperature increases across land since 2000.
“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),” the study found.
In the next decades, significant swaths of South and Southeast Asia, as well as regions straddling the equator in Africa and Latin America, could face a life-and-death threat from longer and more powerful heat waves, according to recent study.