UN agency warns global temperatures will soon breach the safe threshold. What are the risks?

Global temperatures are about to cross the 1.5-degree Celsius threshold that countries sought to avoid under the Paris Agreement, the UN Environment Programme warned in its latest report, titled *Limiting Overshoot*.

UNEP says the best option still available is an “overshoot, peak and decline” pathway. Under that approach, temperatures would rise above 1.5 degrees, reach a peak and then fall. The report says this would limit both the scale and duration of warming beyond the threshold.

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The scorching heatwaves, raging wildfires and deadly floods this summer are warnings of what is to come. We must make the overshoot of 1.5 degrees as small and short as possible. That requires a leap in ambition.

UN Secretary-General Antonio Guterres pointed to recent extreme weather as a warning of what lies ahead. “The scorching heatwaves, raging wildfires and deadly floods this summer are warnings of what is to come. We must make the overshoot of 1.5 degrees as small and short as possible. That requires a leap in ambition,” he said, according to a UNEP press release.

UNEP said the pathway requires immediate and sustained cuts in greenhouse-gas emissions, including methane. Temperatures could later decline through long-term net-negative emissions, with carbon dioxide removal as one component. Such removal takes carbon dioxide out of the atmosphere and stores it, including through reforestation.

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There is no good outcome if we remain above 1.5 degrees Celsius. Extreme heatwaves around the world have proved that climate impacts are coming faster, hitting harder and lasting longer, taking more lives and causing deeper disruption.

Adaptation will also be needed to reduce the vulnerability of people, communities and economies. But UNEP warned that adaptation has limits and that irreversible damage could occur if the temperature peak is not kept down. “There is no good outcome if we remain above 1.5 degrees Celsius,” UNEP Executive Director Inger Andersen said. “Extreme heatwaves around the world have proved that climate impacts are coming faster, hitting harder and lasting longer, taking more lives and causing deeper disruption.”

UNEP said even its most optimistic scenario produces a peak of about 1.8 degrees above preindustrial levels. Other scenarios project higher peaks, increasing threats to ecosystems, small island states, coastal cities, human health, food security, water supplies, infrastructure and economies.

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Now is the time to double down on climate action. We can and must get on the right track by cutting greenhouse-gas emissions, strengthening resilience and adaptation, and ensuring that the overshoot of 1.5 degrees Celsius is as small and short as possible.