Is the climate crisis pushing the world towards a “tipping point”?

It’s a simple unanswered question. Even if humans stopped polluting the world overnight, scientists say it would take many decades for Earth’s climate to reach a new balance. This is largely related to how heat is stored in the world’s oceans, which in turn can have an influence on air temperature.

Things could be further complicated by potential “hotspots” in nature that could be triggered by global warming.

For example, rising temperatures are causing the thawing of permafrost, a frozen ground found in the high northern latitudes that stores large amounts of carbon. This thaw causes more carbon to be released into the atmosphere, which in turn adds to the rise in temperatures. There is a fear that such positive “feedback loops” could eventually lead to rapid warming, and limiting global warming is important to avoid such feedback.

A new study, published today in the journal Scientific reports, makes the bold statement that, hypothetically speaking, we could “already [be] beyond a point of no return for global warming ”.

Using a simplistic mathematical model, it simulates what would happen in a hypothetical world where greenhouse gas emissions were stopped in 2020. It notes that, in the simulations, the world continues to warm up for hundreds of years due to positive feedback cycles such as like the thawing of permafrost.

However, leading climate scientists across the UK and beyond have urged people to take the new study results with extreme caution.

This was stated by Professor Richard Betts MBE, president of climate impacts of the University of Exeter and the Met Office The independent: “Having spoken to various colleagues, we do not feel there is any credibility in the model.

“Feedback is important. The ability to ultimately commit to long-term climate change is important. But there is no real evidence that this has already happened.”

Since the model used in the new study is simplistic, it does not simulate important climate feedback loops well, explains Prof. Betts.

In addition to permafrost thawing, Arctic sea ice melting is also an important potential feedback. Warming of the world’s oceans and atmosphere is causing ice to melt at an astonishing rate. The bright white ice reflects sunlight, and once it disappears, the exposed dark ocean begins to absorb more sunlight, further warming the ocean, leading to further melting of the ice.

While this feedback is important to take into account, the model used in the new study does not well simulate how it works, says Prof. Betts.

The findings also contradict the findings of the upcoming assessment report by the Intergovernmental Panel on Climate Change (IPCC), an independent group made up of the world’s leading climate scientists.

“The results presented in the paper are interesting, but they really run counter to the scientific community’s understanding of how the climate is changing,” says prof. James Renwick, head of the school of geography, environment and earth sciences at Victoria University in Wellington.

“The latest round of climate model simulations shows that if greenhouse gas emissions cease immediately, there is likely to be a very small further rise in temperatures and no signs of warming in the future.”

The models used by the IPCC are more advanced and better able to simulate the behavior of Earth’s feedback loops, says Prof Mark Maslin, a climate scientist at University College London.

“These results need to be confirmed by more complex climate models used in the IPCC reports, because these results come from a model that has not undergone the rigorous cross-checking and testing typical of climate models,” he says.

In their article, the authors emphasize the simplicity of their model by saying that they “encourage other model builders to explore our discovery in their [bigger] models and report on their results “.

It’s important to understand that it’s not too late to take action to tackle the climate crisis, says prof. Betts: “I don’t want people to take [the research paper] seriously and start worrying that climate catastrophe is now inevitable. ”

Claiming that the world is “doomed” to extremely high levels of warming can be detrimental to global efforts to address the climate crisis, explains Leo Barasi, author of Climate Majority.

“He claims the world is irreversibly doomed to uncontrolled warming and that no emissions reductions can help us, he can always find an audience, just as he says climate change is nothing to worry about,” he said. The independent.

“But these claims are usually based on external studies or data that have been taken out of context and ignore all opposing evidence.

“Telling the world that we are doomed, when not supported by the evidence, is irresponsible and unlikely to motivate urgent action that can still prevent disastrous warming.”