Climate scientists say predictions of catastrophic warming are more plausible than previously thought.

What will the future climate look like? Scientists around the world are bringing together Earth system models and large observational datasets to study climate change in hopes of understanding Earth’s climate and predicting the climate for the next 100 years. But which models are the most believable and best reflect the future of Earth’s climate?

In an attempt to answer this question and assess the validity of particular models, EPFL scientists developed a rating system to evaluate climate models produced by the global climate community and included in recent IPCC reports. I have classified the output of .

Climate scientists at EPFL found that about one-third of the models do a poor job of reproducing existing sea surface temperature data, one-third are robust and less sensitive to carbon emissions, and the remaining We found that one-third of the results were also robust, but predictive. A particularly hot future is predicted for the planet due to its high sensitivity to carbon emissions. The results will be published in the journal Nature Communications.

“We show that carbon-sensitive models – models that predict much stronger heating than the most likely IPCC estimates – are plausible and should be taken seriously.” , says Professor Athanasios (Thanos) Nenes of EPFL’s Institute of Atmospheric Processes and Their Impacts. , an affiliated researcher at the Hellas Research and Technology Foundation and author of the study along with graduate student Lucille Ricard.

“In other words, current carbon emission reduction measures based on lower carbon sensitivity estimates may not be sufficient to limit a catastrophically hot future,” Ricard said.

Assessing the validity of climate models: big data analysis

Since the mid-1800s, the scientific community has systematically observed the Earth, measuring climate variables such as temperature, humidity, pressure, wind, precipitation, ocean, and ice conditions on Earth. Particularly over the past few decades, observational networks and satellite deployments have resulted in an enormous amount of observational data, and using this information to predict all future aspects of the climate is a challenging task.

To evaluate a particular climate model, EPFL researchers use machine learning to cluster the climate model’s output, synthesize its behavior by region, and compare the results with existing data. We have developed a tool called “netCS”. With the help of netCS, scientists can determine which climate simulations best reproduce observations in the most meaningful way and rank them accordingly.

“Our approach is an effective way to quickly evaluate a given climate model, thanks to netCS’ ability to sift through terabytes of data in one afternoon,” Ricard said. “Our model assessment is a new type of model assessment and is highly complementary to what we have learned from the historical record, paleoclimate record, and process understanding outlined in the 2021 IPCC AR6 Assessment Report. ”

Mr. Nenes has been invited to participate in the IPCC AR7 scoping conference in Malaysia and is originally from Greece. He recalled that about 30 years ago, when he gave a piano concert in Athens in the middle of summer, he said, “The maximum temperature at that time was between 33 and 36 degrees Celsius, which is considered one of the highest temperatures of the year.” I’ll never forget it.” It was difficult to play the piano in that heat.

“Greece now has summer temperatures often exceeding 40 degrees Celsius. Forest fires are common and have invaded cities, most recently burning my old area. And it gets worse. The Earth is literally on fire. Temperatures are rising continuously around the world and breaking records year after year after year.”

“Sometimes I feel like climatologists are like Cassandra from Greek mythology,” Nenes concludes. “She was given the power of prophecy, but was cursed so that no one would listen to her. But this inertia and lack of action should motivate us, We shouldn’t get discouraged. We collectively have to wake up and get serious about climate change. It’s happening much faster than we thought.”