The goal established in the Paris Agreement to restrict global warming to no more than 1.5°C above pre-industrial levels, adopted over ten years ago, has recently been deemed unfeasible by the United Nations (UN).
According to a new report from the United Nations Environment Programme (UNEP), released this Wednesday (2), it is expected that the rise in global temperatures will surpass the ideal limit in a few years. Even considering the most optimistic projections, it is estimated that the average surface temperature of the Earth could reach 1.8°C this century.
The document highlights that any temperature increase above 1.5°C can generate severe consequences for the world's climate, such as ecosystem collapse, increased extreme heatwaves, and sea-level rise. Additionally, vital life support systems on the planet, such as the Amazon rainforest, are progressively becoming susceptible to irreversible changes known as 'tipping points.'
Inger Andersen, Executive Director of UNEP, stated in a note that 'there are no good outcomes if we continue above 1.5°C. Around the world, extreme heatwaves are already showing that climate impacts will occur faster, be more intense, and last longer – costing more lives and causing deeper disruptions.'
The original 1.5°C goal was set in 2015 in the Paris Agreement, an international treaty signed by 196 nations with the purpose of keeping global temperature increases 'well below' 2°C, a level considered potentially catastrophic for the global climate. Thus, signatory countries committed to implementing measures to reduce greenhouse gas emissions into the atmosphere, aiming to keep warming below this ceiling.
The ideal limit established by the agreement remained the current goal during climate discussions at the UN; the previous year, COP30, held in Belém, concluded with a resolution to 'keep 1.5°C within reach.'
However, in 2024, global surface temperatures recorded an average of 1.55°C, making it the hottest year ever documented and the first to exceed the 1.5°C mark. Although the year 2024 itself did not invalidate the Paris Agreement—as it considers the global temperature average over twenty years—recent estimates on global carbon dioxide emissions already indicated that, maintaining the current pace, the planet would cross the threshold stipulated by the agreement soon.
This new report marks the first time the UN recognizes the 1.5°C goal as impractical. Titled 'Limiting Overshoot,' the document addresses exceeding this threshold and suggests actions to mitigate its effects, minimizing the period during which the planet remains above 1.5°C.
According to the report, in a scenario where global temperatures stabilize around 1.8°C, it would be feasible to return to 1.5°C by the end of the century, following the most optimistic forecasts for temperature decline.
The report states that 'with unprecedented actions, it is possible to minimize and adapt to the impacts of overshoot and return to 1.5°C – which would keep options open to protect the poorest and most vulnerable, minimize damage to infrastructure and livelihoods, and support people and nature.'
To achieve this goal, it would be essential not only a global initiative to change the energy matrix towards clean and renewable sources but also an expansion of efforts to capture and remove carbon dioxide from the atmosphere—an existing and growing technology, but one that is still far from handling the billions of tons of CO2 that would need to be removed annually from the atmosphere.