The world may surpass the key 1.5-degree-Celsius (2.7-degree-Fahrenheit) global warming threshold within the next five years, a major new outlook on climate trends shows. It’s the latest sign that we’re speeding toward the grim future that climate scientists have warned about for years unless we change course.
The report released by the World Meteorological Organisation and the UK Met Office on Thursday says the chance of reaching 1.5 degrees Celsius of heating by 2025 has “roughly doubled” compared to last year’s predictions and now sits at 40%. There’s also a 90% likelihood of at least one year between now and 2025 being the hottest on record.
The 1.5 degrees Celsius threshold is enshrined as the more ambitious goal set by the Paris Agreement. Leading climate researchers have shown that surpassing that target will usher in climate catastrophe, triggering mass species dieoffs, rendering most low-lying islands all but uninhabitable, and worsening extreme weather. Crossing the 1.5-degree-Celsius threshold for a single year would not mean immediately lead to all these consequences.
Global temperatures differ from year to year because of noise in the climate system. For example, natural climate phenomena like El Niño can bump up the annual average temperature. But passing a critical threshold even for a year is still a warning to be heeded.
“These are more than just statistics,” WMO Secretary General Petteri Taalas said in a statement.
We could still meet the target of limiting average temperature rise. But the report, boringly known as the Global Annual to Decadal Climate Update, is a scary sign that overall, warming is accelerating, so the odds that we’ll do so are shrinking — and a wake up call that we need to act quick.
“In a world that has warmed by 1.5 degrees Celsius we expect half of the years to be warmer than 1.5 degrees Celsius, and the other half cooler,” Joeri Rogelj, director of research at the Grantham Institute at Imperial College London, said in a statement, while noting even a single year above the threshold is still “very bad news.”
The dire report comes as climate activists celebrate some rare wins. In a groundbreaking ruling, a Dutch court ordered energy giant Shell to cut its carbon pollution 45% by 2030. And at their annual shareholder meetings, disgruntled investors at Exxon and Chevron rebuked both companies over their failure to implement serious climate plans. Both are positive developments, but the new report reminds us that they’re also not enough.
As UN climate scientists concluded in a groundbreaking 2018 report on the 1.5-degree-Celsius target, “unprecedented changes across all aspects of society” will be needed to secure a livable planet. That means cutting greenhouse gas pollution at an unprecedented rate, halting fossil fuel expansion (as the International Energy Agency called for earlier this month), and winding down emitting projects while phasing polluting industries out of existence.
“It tells us once again that climate action to date is wholly insufficient and emissions need to be reduced urgently to zero to halt global warming,” Rogelj said of the report.