How climate change spreads malaria in Africa, by scientists

A new study, journal Biology Letters, has shown how mosquitoes that transmit malaria have dramatically increased their range over the last century, as temperatures warmed.

The research offers a glimpse of the future by reviewing the past. Mosquitoes transmitting malaria in Sub-Saharan Africa have gone up by about 6.5 metres (roughly 21 feet) yearly and away from the Equator by 4.7 kilometres (about three miles) in the period.

The pace is consistent with climate change and might explain why the disease’s range has expanded over the past few decades, the authors said.

The results have serious implications for countries that are unprepared to cope with the disease.

A biologist at Georgetown University’s Centre for Global Health Science and Security and paper’s lead author, Colin Carlson, said: “If this were random and unrelated to climate, it would not look as cleanly climate-linked.”

Most studies on impact of climate change on health tend to focus on spread of the disease – which could be tricky to trace to any single cause – and be unpredictive. The new study is instead, a retrospective look at how mosquitoes have moved.

The study, also published by New York Times, showed that as the planet warms, plants and animals — particularly invertebrates – are seeking cooler temperatures, either by moving to higher altitudes or by moving closer to the poles. One meta-analysis estimated that, to date, terrestrial species have been moving uphill at a pace of 1.1 metre (3.6 feet) yearly and towards the poles at a pace of 1.7 kilometres (1.1 miles) every year.

Ticks that transmit Lyme disease, for example, are dramatically expanding their range in northern United States. Bats are also on the move, and with them diseases that they transmit, such as rabies.

In the Northeast, lobsters are dying of a fungal disease linked to warming and fish are migrating North or into deeper waters in search of cooler temperatures. That leaves seabirds like puffins with a dwindling food supply and forces commercial fisheries to switch to new types of catch.

“Often we reduce impacts of climate change down to the world just generally getting warmer, and we don’t often think about the vastly interconnected world in which we live,” said Morgan Tingley, an ecologist at the University of California, Los Angeles, United States.

While species have been redistributed on the planet for millions of years in response to the climate, the changes are now “happening radically fast,” he noted.