Record-high greenhouse gas emissions accelerate global warming

Record-high greenhouse gas emissions and decreasing air pollution have created an unparalleled acceleration in global warming, said 50 top scientists on Thursday in a sweeping climate science update.

The study, published in a peer-reviewed journal, published from 2013 to 2022, said that human-induced warming has been increasing at an unprecedented rate of more than 0.2 degrees Celsius per decade.

Average annual emissions over the same period hit an all-time record high of 54 billion tonnes of CO 2 or its equivalent in other gases - about 1,700 tonnes every second.

The new data will be presented to the world leaders at the crucial COP 28 climate summit in Dubai next year, where a Global Stocktake at the UN talks will assess progress toward the 2015 Paris Agreement's temperature goals.

The findings would seem to close the door on capping global warming under the Paris treaty's more ambitious 1.5 degrees Celsius target, long regarded as a guard rail for a relatively climate-safe world, albeit still roiled by severe impacts.

Even though we are not yet at 1.5 C 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, said Piers Forster, a professor of physics at the University of Leeds.

The UN's climate scientist 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 an even a coin-toss chance of staying within the 1.5° Celsius maximum, emissions of carbon dioxide, methane and other drivers of warming generated mostly by burning fossil fuels must not exceed 250 billion tonnes Gt.

Bettering the odds to two-thirds or four-fifths would reduce that carbon allowance to only 150 Gt and 100 Gt, respectively - a two- or three-year lifeline at the current rate of emissions.

Keeping Paris temperature targets in play would require slashing CO2 pollution at least 40 percent by 2030, and eliminating it completely by mid-century, the IPCC has calculated.

The data show that one of the biggest climate achievements of the last decade has inadvertently increased the pace of global warming.