Locust attacks are posing a serious threat to food security in parts of East Africa, India and Pakistan as a result of changing climate conditions that can be linked to human activity, the World Meteorological Organisation (WMO) has said.
The specialised agency of the United Nations said extreme weather events and climatic changes such as increases in temperature and rainfall over desert areas, and the strong winds associated with tropical cyclones, provide a new environment for pest breeding, development and migration.
Large and aggressive swarms of these crop-devouring short-horned insects recently invaded over two dozen districts of desert areas in Rajasthan, Madhya Pradesh and Gujarat.
In Pakistan, authorities declared an emergency in February, saying locust numbers were the worst in more than two decades.
WMO cited an article in Nature Climate Change and said while desert locusts have been here since biblical times, recent intense outbreaks can be linked to anthropogenic climate change and the increased frequency of extreme weather events.
"Attribution of a single event to climate change is difficult. However, climatic changes such as increases in temperature and rainfall over desert areas, and the strong winds associated with tropical cyclones, provide a new environment for pest breeding, development and migration.
This suggests that global warming played a role in creating the conditions required for the development, outbreak and survival of the locusts," scientists from the Intergovernmental Authority on Climate Prediction and Applications Centre said (ICPAC).
The article cited the role of Indian Ocean warming, intense and unusual tropical cyclones in the region and heavy rainfall and flooding as playing an important role.
"The recent locust outbreaks and the role of Indian Ocean warming show that the impact of climate change is not merely the consequences of changes in mean temperature, but also of increases in extreme and unprecedented events."
WMO said the first-wave of infestations at the end of 2019 destroyed 70,000 ha of farmland in Somalia and Ethiopia, and 2,400 km of pasture land in Kenya.
A recent assessment in Ethiopia estimated that between December 2019 and March 2020, locusts damaged 114,000, 41,000 and 36,000 ha of Sorghum, maize and wheat, respectively, according to ICPAC.
ICPAC, which is a WMO regional climate centre, said that locust swarms have been reported in the last 14 days in northern Kenya, eastern and north-eastern Ethiopia.
Adult locusts are also in large numbers in the areas where hoppers and bands were spotted in June which is in the trajectories of migrating swarms.
"This means a continued increase in locust numbers even with the control efforts. Parts of Sudan have had adult locust reported in more locations," it said.
Climatic conditions suitable for desert locust development are forecast to be highly suitable in Uganda, southern to east of Sudan, eastern Ethiopia, northern Somalia and northern Kenya.
The Food and Agricultural Organisation said that new reports of Desert Locust swarms in northern Somalia suggest that migration across the Indian Ocean to the summer breeding areas along both sides of the India-Pakistan border could be imminent.
It added that summer breeding has commenced along both sides of the India-Pakistan border where numerous swarms are present mainly in Rajasthan.
FAO is the lead agency in Desert Locust monitoring and control and runs the Desert Locust Information Service (DLIS). It uses the WMO Global Observing System as input.