There is an “emissions canyon” between current policies and what is required to stop the Earth heating beyond safe limits, the UN has warned.
It said international decarbonisation targets would still leave the world almost 3C hotter by 2100 than it was before the industrial era.
Scientists have frequently warned that going beyond 1.5C and 2C, key targets set in the Paris Agreement eight years ago, could set off irreversible tipping points that would heat the planet beyond human control and lead to catastrophic rises in heat, extreme weather and sea-level rise.
UN Secretary-General Antonio Guterres described this “emissions canyon” as “a failure of leadership, a betrayal of the vulnerable and a massive missed opportunity”.
His comments came at the launch of a report from the UN Environment Programme (Unep) which found global greenhouse gas emissions to have increased by 1.2% from 2021 to 2022 to a new record of 57.4 gigatonnes of carbon dioxide equivalent.
Mr Guterres described fossil fuels as the “poisoned root” of the climate crisis and said there needs to be a tripling of renewables, a doubling of energy efficiency and the availability of clean power to all by 2030.
There must also be credible action from the private sector and “no more greenwashing and no more foot-dragging”, he added.
The window for stopping the average global temperature rising 1.5C above pre-industrial levels is rapidly closing and there is now only a 14% chance of achieving this, the UN said.
Global emissions have to be reduced by 42% by 2030 to meet this target or by 28% to stop the temperature rising above 2C.
Inger Andersen, Unep’s executive director, said humanity is breaking all the wrong records following all-time high temperatures for July through to October and with 2023 almost certain to be the hottest year ever recorded.
Countries are set to publish their decarbonisation targets, known as nationally determined contributions, for 2035 in two years’ time.
The UN said all countries need to be far more ambitious and that none of the G20 nations are reducing emissions at a pace consistent with meeting their net-zero targets.
Emissions from coal, oil and gas in production or in the planning stage would “obliterate” the 1.5C target and fill almost the entire carbon budget for keeping within 2C, Ms Andersen warned.
Richer countries must also decarbonise faster and provide funding to developing nations to help them adapt to the effects of climate change while supporting their transition and growth through renewable power, Mr Guterres said.
Without urgent emissions reductions this decade, climate action in the 2030s will need to be larger and more expensive, Ms Andersen said, with carbon removal technology not yet in place to successfully mitigate greenhouse gas emissions.
She added: “The world needs to lift the needle out of the groove of insufficient action and begin setting new records, on cutting emissions, on green and just transition and on climate finance, starting now.”