The world can no longer prevent global warming from exceeding 1.5°C above pre-industrial levels without or with only limited overshoot, raising concerns about the growing climate risks facing Africa and other vulnerable regions, according to the United Nations Environment Programme (UNEP).
The point of return, UNEP says decades of insufficient climate action have made a larger-than-previously-anticipated overshoot of the 1.5°C threshold unavoidable.
However, countries can still limit peak warming, reduce the time spent above the threshold and potentially return global warming to 1.5°C by the end of the century, the report says.
The chance of holding global warming to below 1.5°C above pre-industrial levels with no or limited overshoot is gone. Every additional fraction of a degree and additional year of warming above 1.5°C will increase climate impacts and risks, such as the deadly floods, heatwaves and wildfires that have plagued many nations this year,” UNEP Executive Director Inger Andersen said.
The report says the immediate priority is to cut greenhouse gas emissions sharply and consistently while expanding efforts to remove carbon dioxide from the atmosphere.
To follow the pathway with the lowest possible overshoot of 1.5°C, global greenhouse gas emissions would need to fall by 18 per cent by 2030, 45 per cent by 2035 and 69 per cent by 2040, compared with 2025 levels. The pathway would limit peak warming to between 1.7°C and 1.8°C around the middle of the century before bringing global temperatures back to or below 1.5°C by 2100, with about a 50 per cent chance.
However, current national climate commitments fall short of the reductions required. UNEP says full implementation of the latest nationally determined contributions submitted by around two-thirds of countries would reduce emissions by only 5 to 8 per cent by 2030 and 11 to 15 per cent by 2035, relative to 2025 levels.
The report projects that full implementation of current pledges would leave the world on course for approximately 2.6°C of warming by 2100, while current policies would result in a projected increase of 2.8°C.
UNEP cautions that returning temperatures to 1.5°C would depend on the world's ability to remove substantial amounts of carbon dioxide from the atmosphere, a process that carries significant technological and socioeconomic uncertainties.
African governments should strengthen investment conditions while pressing for international financial reforms to lower the cost of capital and support national development priorities.
The report identifies the expansion of renewable energy as one area where faster action could help close the gap between existing commitments and the climate goals agreed under the Paris Agreement.
Despite the challenges, UNEP says the global temperature trajectory has shifted since the adoption of the Paris Agreement. Projections based on current policies have fallen from around 4°C of warming before the agreement to 2.8°C today, although this remains well above the agreement's long-term temperature goal.
The report says measures need to be replicated and sustained more widely to bring the world closer to a lower-warming pathway.
Its central warning is that while the opportunity to avoid exceeding 1.5°C has passed, the scale and duration of the overshoot will depend on decisions taken now.
A Guest Editorial