Climate crisis could cause new mass extinction, says researcher
If humanity fails to reverse the impacts of climate change, Earth could face a mass extinction event comparable to that of the Permian Period (299 to 251 million years ago), when approximately 90 percent of species perished under extreme conditions. The warning comes from Hugh Montgomery, director of the Centre for Human Health and Performance at University College London and one of the authors of the 2024 Lancet scientific report on health and climate change.
He opened the Forecasting Healthy Futures Global Summit, an international event on health and climate that began on Tuesday (Apr. 8) in Rio de Janeiro. Brazil was selected to host the meeting in light of its role as the upcoming host of the 30th United Nations Climate Change Conference (COP30) in November.
Montgomery emphasized that this extinction is already underway—“the biggest and fastest the planet has ever seen, and we’re the ones causing it,” he said. However, species loss could reach catastrophic levels if the average global temperature rises by 3 degrees Celsius above pre-industrial levels. In 2024, the world registered a record increase of 1.5°C, and scientists estimate that, if current trends continue—particularly in relation to greenhouse gas emissions—temperatures could rise by 2.7°C by 2100.
“If we keep striking the base of the unstable pillar we stand on, humanity itself will be threatened,” the expert warned. “Last year alone, we released 54.6 billion tons of CO₂ equivalent into the atmosphere—an increase of nearly 1 percent compared to the previous year. And the concentration of CO₂ in the atmosphere isn’t just rising; it’s accelerating.”
According to Montgomery, other drastic consequences could occur well before then. “If global temperatures rise—even temporarily—by between 1.7°C and 2.3°C, we could see a sudden collapse of Arctic ice sheets,” he warned. “This would also lead to a significant slowdown of the Atlantic Meridional Overturning Circulation, a key driver of our climate system, within the next 20 to 30 years. The result would be a rise in sea levels by several meters, with catastrophic consequences.”
He also highlighted other drivers of global warming, such as methane emissions—a gas with a harmful potential 83 times greater than carbon dioxide, primarily released during natural gas extraction. The British scientist emphasized that immediate action to reduce atmospheric pollution is crucial, not only for the environment but for the global economy. He warned that, starting in 2049, climate change could shrink the world economy by 20 percent annually—equivalent to a loss of $38 trillion per year.
Hugh Montgomery believes it is crucial to consider adaptation measures, as climate change is already impacting public health. However, he warns that this must not come at the expense of urgent and drastic emissions reductions. “There’s no sense in focusing solely on relieving the symptoms when we should be pursuing a cure,” he said.
