The 1.5C climate target is almost dead

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Global temperatures could rise as high as 1.9C above the pre-industrial average over the next five years, according to new data from the World Meteorological Organisation (WMO). It’s the first time climate models have predicted such a large increase, and 2C is not out of the question.

So what? The Paris treaty aimed to limit the increase to 1.5C, a threshold that was breached for the first time last year, while also setting the goal of keeping the rise “well below” 2C. If temperatures were to reach 2C, that could

• kill 99 per cent of coral reefs, with devastating consequences for marine life;
• wipe out 18 per cent of the world’s insects; and
• bring ever more frequent floods, droughts and wildfires, which displaced 800,000 people last year.

Rising. Surpassing 1.5C for a single year does not mean the original target of the Paris agreement is dead just yet. It would have to happen annually for several years.

High chance. The report released today by WMO says there’s now a 70 per cent chance average warming will rise by more than 1.5C between 2025 and 2029, with a strong possibility of a single year hitting 1.9C.

Throwback. That is a stark change from 2015, when the Paris accord was struck in a mood of optimism. Back then, meteorologists thought there was a zero to 1 per cent chance a single year would exceed 1.5C in the subsequent five years.

Grim outlook. Overall, the new modelling from the WMO predicts temperature rises will continue to be “at or near record levels”. Specifically, it forecasts

• warming in the Arctic at three and a half times the rate in the rest of the world, reaching 2.4C above the average for the last 30 years;
• more rainfall in Siberia, northern Europe and Africa’s arid Sahel region; and
• drier conditions in the Amazon, which is already suffering record wildfires caused by drought.

More worryingly the WMO believes there is a one per cent chance of breaching the 2C threshold at some point between now and 2029, something Professor Adam Scaife from the British Met Office says would be “completely unprecedented”.

That might sound small, but it's significant. Scientists once thought a rise of this magnitude was almost impossible in such a short time. Now it is part of the range of outcomes modelled by their supercomputers.

Down. Changes in the climate are not linear. Before 2023, the world experienced a La Niña effect for three years. This weather pattern cools global surface temperatures.

Up. The opposite is an El Niño event, which warms waters in the eastern Pacific Ocean near South America. Last year saw one of the strongest El Niños on record. Along with emissions, this was partly why temperatures were so high.

Melting the ice. For every rise of even a fraction of a degree, more ice melts in the polar regions. The particularly fast warming of the Arctic is a result of shrinking ice cover, less snow to reflect sunlight back into space, and a darker Arctic Ocean, absorbing more heat and creating a warming feedback loop.

Team effort. The WMO’s predictions are based on 220 forecasts from 15 different countries including Spain, Canada and Germany. The Met Office is the lead agency.

What’s more… the WMO factored in emissions reductions into its models. Even if we suddenly halted them all now, temperatures would still rise because the climate would not respond immediately.

Photograph by Luis Tato/AFP via Getty Images