Wind-whipped mayhem may ratchet up as the global climate adjusts to ever increasing concentrations of greenhouse gases in the atmosphere, according to a new study.
In particular, easterly winds associated with weather systems known as African easterly waves that bring rains critical to crops and livestock in the Sahel, transport Saharan dust within Africa and across the Atlantic Ocean, and play a role in the formation of tropical cyclones –- i.e. hurricanes –- will strengthen.
"Even though only about one in seven African easterly waves develop into a tropical cyclone, something on the order of 80 percent of the intense tropical cyclones are linked" to them, said Noah Diffenbaugh, a climate scientist at Stanford University in California and a study co-author.
There are caveats, however. Just because the winds associated with the waves will become more intense in a warming world does not necessarily mean that hurricanes will be stronger or more frequent in the future.
Rather, "in order to more fully understand the response of tropical cyclones to global warming, we need to consider how (African easterly waves) may change themselves," Christopher Skinner, a graduate student in Diffenbaugh's lab and co-author of the study, told NBC News in an email.
The scientists based their study on 17 model simulations of Earth's climate with carbon dioxide concentrations about double what they are today, which is the current trajectory for the end of this century if greenhouse gas emissions remain unchecked.
Under this scenario, they found that the waves strengthen due to a rising difference between temperatures in the Sahara and the Guinea coast, to the south. This "results in greater potential energy for weather systems such as (African easterly waves) to draw from," Skinner explained. "As a result (the waves) intensify."
Findings are published today in the Proceedings of the National Academy of Sciences.