Carbon emissions have caused the stratosphere to shrink by 400 meters since the 1980s, according to a new study published in the journal Environmental Research Letters. The study further found that if action is not taken to reduce current emission rates, the vital atmospheric layer will shrink another 1 kilometer by 2080. This would adversely affect satellite operations, GPS navigation and radio communications.
The stratosphere is the second atmospheric layer after the troposphere. It is found between 20 and 60 kilometers above the Earth’s surface and is important in many ways. It is home to the ozone layer, which protects the Earth from harmful UV rays. When carbon dioxide heats and expands in the troposphere below, it pushes the lower boundary of the stratosphere. Alternatively, as carbon dioxide reaches the stratosphere, it instead cools the air and causes it to contract.
Researchers used satellite observations taken since the 1980s in combination with modern climate models to arrive at the conclusion. Although experts have long known that the stratosphere was shrinking, it was initially thought that it was caused by the depletion of the ozone layer. However, the new study now proves that the shrinking is caused by CO2 emissions. The ozone layer has recovered since 1989, when CFCs were banned. But the stratosphere has continued to shrink over this period.
“This study finds the first observational evidence of stratosphere contraction and shows that the cause is, in fact, our greenhouse gas emissions rather than ozone,” said Paul Williams, professor at the University of Reading. Williams was not involved with the study.
“Some scientists have started calling the upper atmosphere the ‘ignorosphere’ because it is so poorly studied,” he said. “This new paper will strengthen the case for better observations of this distant but critically important part of the atmosphere.”