1°C between life and death!

Limiting warming to half-degree Celsius from now means the world can keep "a semblance" of the ecosystems we have.

• In gloomy state of Earth report, UN climate panel sets a deadline to act.

Preventing an extra single degree of heat could make a life-or-death difference in the next few decades for multitudes of people and ecosystems on this fast-warming planet, an international panel of scientists reported on Sunday. But they provide little hope the world will rise to the challenge.

The Nobel Prize-winning Intergovernmental Panel on Climate Change issued its gloomy report at a meeting in Incheon, South Korea. In the 728-page document, the UN organisation detailed how Earth's weather, health and ecosystems would be in better shape if the world's leaders could somehow limit future human-caused warming to just a half degree Celsius from now, instead of the globally agreed-upon goal of 1° Celsius."For some people this is a life-or-death situation without a doubt," said Cornell University climate scientist Natalie Mahowald, a lead author of the report.

Limiting warming to half-degree Celsius from now means the world can keep "a semblance" of the ecosystems we have. Adding another half-degree Celsius on top of that - the looser global goal - essentially means a different and more challenging Earth for people and species, said another of the report's lead authors, Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland, Australia.

But meeting the more ambitious goal of slightly less warming would require immediate, draconian cuts in emissions of heat-trapping gases and dramatic changes in the energy field. While the UN panel says technically that's possible, it saw little chance of the needed adjustments happening.

In 2010, international negotiators adopted a goal of limiting warming to 2°C since pre-industrial times. It's called the 2-degree goal. In 2015, when the nations of the world agreed to the historic Paris climate agreement, they set dual goals: 2°C and a more demanding target of 1.5°C from pre-industrial times. The 1.5 was at the urging of vulnerable countries that called 2 degrees a death sentence.