Studying the Earth’s stratosphere reduces uncertainty about future climate change

New research led by the University of East Anglia (UEA) reduces uncertainty about future climate change linked to the stratosphere, which affects life on Earth.

Human-induced climate change is one of the biggest challenges we face today, but uncertainty about the true extent of global change hinders effective responses.

One source of uncertainty is related to future changes in water vapor in the stratosphere, the driest region of the atmosphere 15-50 km from Earth.

Future increases in water vapor here could lead to climate change and slow the recovery of the ozone layer, which protects life on Earth from harmful solar radiation.

Now an international team led by Peer Nowack, until recently a member of the Climatic Research Unit at UEA, has developed a new statistical study method that combines information from satellite observations and technical climate data to reduce the possible future stratospheric water vapor volume.

One of the main results is to eliminate the most dangerous events, which means that the amount of steam can increase by 25% at the level of global warming. The new method represents a 50% reduction in 95% of weather responses. The study, “Response of stratospheric water vapor to satellite-driven warming,” was published in Nature Geoscience.

“Man-made climate change affects the Earth’s atmosphere in many important and surprising ways,” said Prof Nowack, who is now at the Institute of Theoretical Informatics at the Karlsruhe Institute of Technology, Germany.

“In our paper, we look at the changes in stratospheric water vapor under global warming, the effects of which are still not fully understood. This long-term uncertainty.

“With our new data-driven approach, which uses machine learning concepts, we were able to make the most of real-world events to reduce this uncertainty. This required us to create a system that would combine scientific understanding with the mathematical relationships we learned from satellite data in ‘new methods.’

“With this method, we were able to show that most of the climate predictions of the major changes in stratospheric water vapor now do not match the observational evidence,” said one author Dr. Sean Davis, Research Scientist at the National Oceanic and Atmospheric Administration in the US, specializes in satellite measurements of stratospheric water vapor.

Estimating the amount of stratospheric water vapor under global warming is a challenge that has been ongoing for some time. The complexity of the processes that control stratospheric water vapor and the short history of high-resolution satellite observations have made this task difficult.

The existence of so-called climate change poses another problem, as it can increase or decrease global warming, leading to future warming.

The amount of water vapor that the stratosphere holds is an example of one such feedback, which climate models have predicted will increase, but the increase in variation has been very large over the years.

This is important, because the large increase in water vapor induced by the climate, as expected by many climate models, could delay the recovery of the ozone layer and the Antarctic ozone hole in this century.

However, Manoj Joshi, Professor of Climate Dynamics at UEA and a co-author of the paper, said, “Our research shows that although the amount of water vapor in the ocean continues to increase with global warming, large-scale changes that would delay the recovery of the ozone layer are highly unlikely.”