Act now or risk climate disaster, warns UN secretary general

The world is still underestimating the risk of catastrophic climate breakdown and ecosystem collapse, the UN secretary general has warned in the run-up to Cop29, acknowledging that the rise in global heating is on course to soar past 1.5C (2.7F) over pre-industrial levels.

- Patrick Greenfield

Humanity is approaching potentially irreversible tipping points such as the collapse of the Amazon rainforest and the Greenland ice sheet as global temperatures rise, António Guterres has said, warning that governments are not making the deep cuts to emissions needed to limit warming to safe levels.

Speaking to the Guardian, the UN secretary general said that a second US departure from the Paris climate agreement under a new Donald Trump presidency would risk crippling the process but said the accord would survive.

With wildfires, drought and extreme weather already ravaging parts of the planet, new research raises concerns about the stability of natural carbon sinks that underpin decarbonisation efforts. Forests, plants and soil - as a net category - absorbed almost no carbon in 2023 during the hottest year on record. While the collapse of land carbon sinks may be temporary, scientists have warned that cracks in the resilience of the Earth's systems are beginning to show.

Guterres urged greater coordination on the interlinked environmental crises of the 21st century, warning that it was impossible to take action on global heating without action on biodiversity loss to protect forests and other carbon stores and sinks.