Global warming is now projected to outpace previous estimates, with even the most optimistic climate scenario showing average temperatures rising to 1.7 to 1.8 degrees Celsius above pre-industrial levels by mid-century, according to a United Nations report released on Wednesday.
While the report acknowledges a rapid expansion of renewable energy and climate policies that are actively reducing emissions across many nations, it emphasizes that urgent and stringent cuts remain necessary to achieve even this best-case outcome.
The findings, published by the UN Environment Programme, state that global greenhouse gas emissions must fall by 18 percent from 2025 levels by 2030. The required reductions deepen significantly thereafter, calling for a 45 percent drop by 2035 and a 69 percent reduction by 2040. In contrast, current national climate plans are projected to cut emissions by only 5 to 8 percent by 2030 and just 11 to 15 percent by 2035.
Looking further ahead to the year 2100, the report projects global warming to reach 2.8 degrees Celsius under current policies, or 2.6 degrees Celsius if governments fully implement their existing climate pledges. Both long-term estimates exceed last year’s projections, a shift driven by the United States’ withdrawal from the Paris Agreement and updated assessments of historical emissions.
The updated projections arrive as countries prepare for the upcoming COP31 climate talks in Turkey. Addressing the sobering trajectory, UN Secretary-General António Guterres urged the international community not to abandon efforts to curb the emissions driving extreme weather events, including severe floods and wildfires.
“Overshoot is not surrender. We can still keep it as small and as short as possible – and bring temperatures back below 1.5 degrees by the end of the century,” Guterres said.
Under the landmark 2015 Paris Agreement, nations committed to holding the global average temperature increase to well below 2 degrees Celsius while pursuing efforts to limit the rise to 1.5 degrees Celsius. However, limiting warming to 1.5 degrees Celsius with no or limited overshoot is no longer considered possible by researchers.
Consequently, the UN Environment Programme outlined a new lowest-possible overshoot scenario. This pathway provides roughly a 50 percent chance that global temperatures could peak and eventually return to 1.5 degrees Celsius or lower by 2100.
Despite this potential pathway, the report notes that climate plans submitted over the past year have made virtually no measurable difference to future warming projections. Furthermore, successfully reversing temperature increases to meet the 1.5-degree threshold would depend heavily on large-scale carbon removal technologies, the large-scale feasibility of which remains uncertain.
