Global temperatures will breach the one point five degree warming threshold

Peak warming is projected to reach 1.7 to 1.8 degrees Celsius even under aggressive emissions cuts, leaving the planet reliant on carbon removal to reverse course.

When fossil fuels burn, carbon dioxide enters the atmosphere and traps heat radiating from Earth's surface. Because carbon dioxide remains in the atmosphere for centuries, every ton emitted adds to an accumulating reservoir that continues to warm the planet. Halting that temperature increase requires reducing net emissions to zero, cutting off the addition of new heat-trapping gases. When renewable energy installations expand while fossil fuel extraction and combustion continue to increase, the atmospheric blanket thickens and global temperatures continue to rise.

That physical reality has now overtaken the primary ambition of international climate policy. In the Emissions Gap Report 2026: The Point of Return, the United Nations Environment Programme found that holding global warming to 1.5 degrees Celsius above pre-industrial levels can no longer be achieved without first exceeding that boundary.¹² Even under the most ambitious emissions-reduction scenarios evaluated in the assessment, the planet is projected to overshoot the target and experience peak warming of 1.7 to 1.8 degrees Celsius by roughly the middle of the century.¹²

The findings mark a structural change in how international climate targets must be understood. The 2015 Paris Agreement established an international commitment to keep global warming well below 2 degrees Celsius while pursuing efforts to limit the increase to 1.5 degrees Celsius, equivalent to 2.7 degrees Fahrenheit.²¹ Inger Andersen, the executive director of the United Nations Environment Programme, stated during a press briefing that exceeding the lower threshold does not mean the world should abandon the target.² Andersen emphasized that every additional fraction of a degree and every additional year of warming above 1.5 degrees Celsius magnifies climate impacts and risks, citing deadly floods, severe heatwaves, and wildfires that have afflicted communities across the world.¹²

What happens when global temperatures exceed one point five degrees?

Exceeding 1.5 degrees Celsius of warming intensifies extreme weather events, raises sea levels, and increases the frequency of severe ecological disruptions across the planet.¹² Andersen warned that a world experiencing more than 2 degrees Celsius of warming would see regular recurrences of recent climate disasters, pointing to the heatwaves that struck much of Europe, wildfires in Scandinavia, and escalating droughts and crop harvest failures.² Western Europe experienced thousands of heat-related fatalities during the spring and summer of 2025, an interval that included four of the region's 10 most severe heatwaves recorded since 1950.²

Robert Kopp, a climate scientist and professor at Rutgers University in New Jersey, said the findings of the assessment were not surprising.² Kopp noted that even when international diplomats adopted the 2015 Paris Agreement, limiting the global temperature increase to 1.5 degrees Celsius was already at the edge of what scientists considered physically and economically feasible.²

UN Secretary-General António Guterres stated in a message accompanying the report that exceeding the threshold should not be treated as a permanent defeat.¹ “Overshoot is not surrender,” Guterres said. “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.”¹

Why did rapid renewable energy growth fail to stop the warming?

Clean power generation expanded at an unprecedented pace over the past decade, but it grew alongside fossil fuels rather than fully displacing them. The report found that global renewable electricity capacity expanded three times faster than analysts anticipated in 2015, while solar photovoltaic installations expanded seven times faster than original projections.² Total energy supply derived from coal and oil grew more slowly than earlier forecast models anticipated, yet total emissions from oil, gas, and coal combustion continued to rise worldwide.¹²

Anne Olhoff, the director of the UNEP Copenhagen Climate Centre and the report's lead author, stated at a press briefing that global greenhouse gas emissions in 2025 were comparable to those recorded in 2024.² Olhoff characterized that stabilization as a welcome divergence from the upward growth trend seen over past decades, although emissions remain far above the trajectory required to halt warming.²

Jan Minx, head of the Evidence for Climate Solutions working group at the Potsdam Institute for Climate Impact Research and a co-author of a chapter in the report, described the overall warming projections as bleak even as wind and solar deployment outpaced historical expectations.² Setu Pelz, a research scholar at the International Institute for Applied Systems Analysis who also co-authored a chapter in the report, emphasized that governments must sustain this clean energy momentum to triple renewable generation capacity by 2030, a key milestone established under the Paris Agreement framework.²¹ Pelz stated that the analytical evidence provided in the report is intended to inform discussions on 2030, 2035, and 2040 sector targets, with the goal of matching the ambition of the renewable capacity scale-up within the fossil fuel transition.²

What emissions cuts would be required to reverse the overshoot?

Bringing global temperatures back to 1.5 degrees Celsius by 2100 requires immediate, steep reductions in greenhouse gas output coupled with large-scale removal of carbon dioxide from the atmosphere.¹² To achieve the lowest-warming overshoot scenario modeled in the report, global emissions must fall by 18 percent by 2030, 45 percent by 2035, and 69 percent by 2040, using 2025 emission levels as the baseline.¹² The pathway also depends on halting and reversing deforestation, curbing non-carbon-dioxide greenhouse gases, and deploying carbon dioxide removal technologies that remain in early stages of technical and commercial maturity.¹²

The assessment outlines specific sectoral benchmarks needed to keep the lowest overshoot pathway within reach. Extending the transition away from fossil fuels would require reducing the share of coal, oil, and gas in total global energy supply by at least 55 percent, 15 percent, and 5 percent respectively by 2035, relative to 2025 figures.¹ By 2040, those mandatory reductions rise to at least 75 percent for coal, 30 percent for oil, and 35 percent for natural gas relative to 2025 levels.¹

The report also evaluated the gap between these requirements and current policy trajectories. If existing government policies continue without intensification, global warming is projected to reach 2.8 degrees Celsius by 2100 and continue rising into the following century.¹² Even if every nation fulfills all current nationally determined contributions pledged under the Paris Agreement and maintains comparable efforts thereafter, global temperature rise is projected to reach 2.6 degrees Celsius.¹ These updated projections represent a worsening compared to the previous year's evaluation, driven by revised calculations of historical emissions and the withdrawal of the United States from the Paris climate agreement under President Donald Trump, which occurred for a second time in 2025.¹² Pledges submitted since the prior assessment have produced negligible changes in projected warming.¹

What can these projections tell policymakers about the future?

The scenarios in the assessment are policy projections based on integrated economic and energy models, not definitive forecasts of exact future temperatures or weather on specific calendar dates. They illustrate how atmospheric greenhouse gas concentrations and surface temperatures will evolve under explicit sets of economic assumptions, regulatory choices, and technological adoption rates. Like all century-scale climate models, the results rely on assumptions about global economic growth, energy demand trends, and the technical viability of scaling atmospheric carbon removal to billions of tons per year.

These modeled outcomes do establish the scale of immediate mitigation required from governments. International negotiations will confront these benchmarks during the second Global Stocktake process at the United Nations COP31 climate conference in Antalya, Türkiye. Achieving the 2030 target of doubling the annual rate of energy efficiency improvements and tripling renewable capacity will determine whether global warming peaks within reach of 1.7 degrees Celsius or climbs toward levels that overwhelm human adaptation.¹

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1. 1 UN UN News Third-party reporting · news.un.org · 21 Oct 2026 Global warming will breach 1.5°C – but deep, fast cuts can still bring it back See the source
2. 2 LD Lauren Dalban, Inside Climate News Document · zmescience.com · 22 Oct 2026 The World Is Set to Blow Past 1.5 Degrees Celsius of Warming and the Consequences Could Be Devastating See the source