Scientists issue 'ultimatum' about Earth's last endurance

The much-anticipated report was delayed due to last-minute arguments over the exact wording of the document. Limiting global warming to 1.5 degrees Celsius above pre-industrial levels would require greenhouse gas emissions to peak by 2025 at the latest. At the same time, methane emissions would also need to be reduced by about 1/3.

The United Nations Intergovernmental Panel on Climate Change (IPCC) said it was almost inevitable that humanity would quickly surpass the critical temperature threshold of 1.5 degrees Celsius in this scenario. But Earth's temperature could be back below this level by the end of the century.

Jim Skea, co-chair of the IPCC's Working Group III, said in a statement accompanying the report: "We need to act now or never, if we are to limit global warming in 1.5 degrees Celsius. Without immediate and far-reaching emissions cuts across all sectors, it will not be possible to do so in the future."

An immediate reduction in greenhouse gas emissions is needed if global warming is to be limited.

The 1.5 degrees Celsius target is the heat threshold set forth in the landmark 2015 Paris Agreement. It is recognized as a global target because if it exceeds this level, the Earth is at risk of reaching " tipping point". This is the threshold where small changes can lead to more catastrophic changes in Earth's entire life-support system.

Julia Steinberger, an ecological economist and professor from Switzerland's University of Lausanne, told CNBC by phone: "The first thing is, we're on the wrong track, both in terms of trajectory and also in policy, we're not. We can't continue to keep 1.5 or even 2 degrees Celsius."

The IPCC's latest report comes after a series of extreme weather events that shook the world. A few weeks ago, for example, an iceberg the size of New York City collapsed in Antarctica.

The disaster scenario prompted a climate strike last month. Hundreds of thousands of environmental activists from 93 countries around the world marched with the banner #PeopleNotProfit.

IPCC President Hoesung Lee said humanity was at a "crossroads", but the tools and know-how needed to limit global warming were still available.

The United Nations Climate Commission has said that to keep global temperature rise below 1.5 degrees Celsius this century, emissions must be halved.

The IPCC scientists also echoed their call to cut fossil fuel use to limit global warming to 1.1 degrees Celsius above pre-industrial levels.

Global average annual greenhouse gas emissions were at their highest levels in human history from 2010 to 2019, the report said, but the rate of increase has slowed. This coincides with a growing body of evidence for climate action.

But the report warns that limiting global temperatures to 1.5 degrees Celsius will not be possible without immediate and profound emissions reductions across all sectors.

These cuts will require major transformations in the energy sector, including a drastic reduction in fossil fuel use, widespread electrification, improved energy efficiency and the use of renewable energy, the report said. alternative fuels such as hydrogen.

Cities are believed to offer significant emissions reduction opportunities. This can be achieved through lower energy consumption, vehicle electrification, combined with low-emission energy sources, and increased carbon sequestration and storage naturally, the report says. .