'Timely wake-up call': Greenhouse gas emissions at all-time high

The team of 50 scientists, led by the University of Leeds with researchers from around the world including Maynooth University, found that even since the last assessment two years ago, human-caused global warming has continued to gather pace.

A record level of greenhouse gases is being emitted each year, equivalent to 54 billion tonnes of carbon dioxide, the researchers calculated. 

They added that the remaining carbon budget — how much carbon dioxide can be emitted to have a better than 50% chance of holding global warming to 1.5C — has halved over three years.

In 2020, the UN-backed Intergovernmental Panel on Climate Change (IPCC) calculated the remaining carbon budget was around 500 gigatonnes of carbon dioxide. By the start of 2023, the figure was roughly half that at around 250 gigatonnes of carbon dioxide.

Prof Thorne said it is a "timely wake-up call" that climate crisis action taken so far is not nearly enough.

“It is critical that policy makers and the general public be made aware of how quickly we are changing the climate through our collective activities. Already since the IPCC assessment of the physical science basis in 2021, key numbers have changed markedly and we remain well off track globally to avert warming above 1.5C," he said.

The IPCC concluded in August 2021 that it was "unequivocal" that human activity is warming the planet, causing rapid and widespread changes to land, atmosphere, and oceans.

The changes, which are unprecedented for many centuries or even many thousands of years, have pushed up global temperatures by 1.1C, and are driving weather and climate extremes in every region across the world.

It said global warming of between 1.5C and 2C — limits countries have committed to in order to avoid the most dangerous impacts of climate change — will be unless deep reductions in greenhouse gas emissions occur in the coming decades.

Human-induced warming averaged 1.14C over the last decade, the latest research found.

This is up from 1.07C between 2010 and 2019. Human-induced warming is now increasing at a pace of over 0.2C per decade, the research calculated.

The Indicators of Global Climate Change Project is being co-ordinated by Professor Piers Forster, Director of the Priestley Centre for Climate Futures at Leeds. 

He 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.

“Long-term warming rates are currently at a long-term high, caused by highest-ever levels of greenhouse gas emissions. But there is evidence that the rate of increase in greenhouse gas emissions has slowed.

“We need to be nimble footed in the face of climate change. We need to change policy and approaches in the light of the latest evidence about the state of the climate system. Time is no longer on our side."