According to the new report by the United Nations Environment Programme (UNEP), it is now inevitable that global temperatures will rise more than 1.5 degrees Celsius above pre-industrial levels within the next few years. Scientists state that a new phase in climate policy is therefore necessary. The UN has consequently introduced a new approach focused on making the overshoot as low and short-lived as possible.
The UN report compiles assessments from approximately 50 leading climate scientists. For the first time, the UN acknowledges in this report that the 1.5-degree threshold will inevitably be exceeded. Nevertheless, the 1.5-degree target set by the Paris Agreement remains valid, but current emission reduction policies are not progressing fast enough to prevent this limit from being surpassed.
New roadmap for temperature increase
UNEP's proposed approach is defined as "overshoot, peak, and decline." According to this, the goal is for global temperatures to first rise above 1.5 degrees, then peak at a certain level, and subsequently decrease again through the reduction of greenhouse gases in the atmosphere.
For this scenario to be implemented, global greenhouse gas emissions need to be reduced by 55 percent by 2035, and emissions must be almost entirely eliminated by the middle of the century.
According to the report, if these steps are taken, the global temperature increase could peak at approximately 1.8 degrees Celsius. Afterwards, it might be possible to lower temperatures again through methods like carbon removal.
Even under current conditions, we are experiencing radical climate events. A peak of 1.8 degrees will lead to much more severe consequences. Rising sea levels will threaten small island nations and coastal communities. Heatwaves, hurricanes, forest fires, and floods will become much more intense than they are currently.
It is predicted that global food production could decrease by 14 percent if necessary adaptation measures are not taken.
Carbon removal from the atmosphere will be necessary
To reduce temperatures again later, simply cutting greenhouse gas emissions will not be enough. According to the report, large quantities of carbon dioxide will also need to be removed from the atmosphere.
For this, in addition to natural methods like expanding forests, technologies that directly capture carbon dioxide from the air and store it underground can also be utilized. In the best-case scenario, these methods could limit the duration for which the world remains above 1.5 degrees to a few decades.
However, carbon removal is not an easy solution that can replace emission reductions. The world currently removes approximately 2 gigatons of carbon dioxide from the atmosphere annually. This amount corresponds to only 5 percent of humanity's annual emissions.
According to calculations, even increasing carbon removal efforts fivefold from current levels could require approximately 50 years to reverse 10 years of temperature increase occurring at the current rate of warming.
Although the report suggests methods like afforestation and carbon removal, it does not claim they will be easy. Even if massive forests are created, carbon stored for years could be released into the atmosphere as a result of just one fire.
Technologies that directly capture carbon dioxide from the air are still very expensive. Moreover, there is no proof that they will work on a large scale.
Returning will not bring back what was lost
A future reduction in global temperatures does not mean that all damages incurred during the overshoot of the 1.5-degree threshold will be eliminated.
According to the report, at least a quarter of the world's glaciers could melt permanently. Extinct species cannot be brought back. Some ecosystems damaged by extreme weather events will also not be able to return to their former state.
Even a temporary overshoot of the 1.5-degree threshold increases the risk of triggering certain critical "tipping points." The report cites the collapse of the Amazon rainforest and the sudden disintegration of polar ice sheets as examples of these risks. Once these processes begin, reversing them is very difficult and likely impossible.
Remaining above the 1.5-degree global warming threshold for an extended period will further inflate the cost. Millions, even billions, of people will be forced to live in a more dangerous and unequal world under this scenario.
2025 record broken
Despite UN reports and calls from scientists, global greenhouse gas emissions reached record levels in 2025. Last year, global temperatures rose 1.3 to 1.4 degrees Celsius above the pre-industrial average, and according to UNEP's 2025 assessment, current policies could lead to a 2.8-degree warming by the end of the century. Even if the most ambitious net-zero targets are fully implemented, the increase is still expected to be around 1.9 degrees.
The new report, however, paints a clearer picture than previous assessments. There is no longer any possibility on the table. The 1.5-degree threshold will inevitably be exceeded within the next few years.
For temperatures to be brought back down to the 1.5-degree level, the peak warming must not exceed approximately 1.8 degrees Celsius. This requires moving away from fossil fuels, transforming energy systems, and reducing potent greenhouse gases like methane. Moreover, time is certainly not on humanity's side, as every five-year delay in emission reductions raises the eventual temperature peak by at least 0.1 degrees Celsius.
Even if emissions are rapidly reduced and large amounts of carbon are removed from the atmosphere, it is not certain that temperatures will fall back below 1.5 degrees Celsius.
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