As temperatures rise, many tropical species once confined to the warmest parts of the globe are expected to climb to higher altitudes and creep farther from the equator.

That already may be happening with mosquitoes carrying malaria, one of the world’s most devastating diseases and one that already kills more than 600,000 people a year. Evidence shows the insects are flapping their tiny wings to new locales in Africa, according to a new study.

Using data dating back to 1898, a team of Georgetown University researchers found the limits of the malaria mosquitos’ ranges moved away from the equator by 4.7 kilometers (2.9 miles) a year on average over the past century.

Mosquitos did some mountain climbing, too, with species gaining an average of 6.5 meters (21.3 feet) in elevation annually on the continent during the same time period, according to a paper published Tuesday in Biology Letters.

Colin Carlson, a biologist at Georgetown who led the paper, said he needs more data to draw a direct link between the spread of malaria mosquitos and rising temperatures.

“But what we can say is a lot of these species are moving in the direction and at the speed that looks like a climate change impact,” he said.

The deadliest impacts of climate change won’t just come from floods, droughts and other disasters. According to top U.N. climate scientists, some of the worst consequences will come from disease.

Few if any diseases have beset humanity as severely or for as long as malaria. The pathogen is ancient, so old it may have infected the dinosaurs. During human history, it may be responsible for killing half of all people who have ever died, according to one estimate.