The Horn of Africa (eastern region of the continent) is battling a serious locust outbreak, the worst the region has seen in the past 25 years. The outbreak, described by the UN Food and Agriculture Organisation (FAO) as ‘extremely alarming’, threatens livelihoods and food security in a region that has already been grappling with the effects of floods, landslides, droughts and cyclones brought on by climate change. The UN has warned this outbreak will continue to develop in lands as far as India, which has already been dealing with the problem since last year, especially in Rajasthan.
According to the FAO, locust swarms have already destroyed vast areas. In Kenya, a single large swarm covered an area of 40km by 60km, which is able to consume as much food in a single day as 85 million people, while in Ethiopia, the swarms have covered more than 429km². A major food security problem is at hand for the continent with projections that the locust numbers could increase 500 times by June.
The region has been hit with unprecedented heavy rain since October 2019, which, scientists believe has fuelled the swarm. Typically, locusts thrive in wet conditions, especially after floods and cyclones. This is because heavy rain leads to vegetation growth in arid regions – creating the perfect conditions for locusts to survive and reproduce.
“In the past few years, there has been a significant increase in the frequency of such cyclones at the beginning and end of the summer period. For example, there were 8 cyclones in 2019 when in most years there are only one or two. Three cyclones in 2018 and two in 2019 have contributed to the current Desert Locust upsurge in the Horn of Africa where large and numerous swarms are present in Ethiopia, Somalia and Kenya,” Keith Cressman, Senior Locust Forecasting Officer, FAO said.
“If this trend continues, whether it is specifically attributed to climate change or not, is likely to lead to more Desert Locust outbreaks and upsurges in the Horn of Africa.”
The climate change link
So why exactly is this region battling extreme weather? This is because of an ocean circulation pattern known as the Indian Ocean Dipole (IOD), which affects climatic conditions stretching from Africa to Australia. It is described as “an irregular oscillation of sea surface temperatures in which the western Indian Ocean becomes alternately warmer (positive phase) and then colder (negative phase) than the eastern part of the ocean”.
In 2019, the positive phase of the IOD was the strongest ever in the past six decades, leading to the extreme weather in Africa as well as the bushfires in Australia. Scientists believe the reason why the positive phases of the IOD are becoming increasingly common is climate change.
As greenhouse gases emitted from human activity continue to warm oceans and the atmosphere, these positive phases could occur at least 3 times more often this century if emissions are not checked, one study predicted. Another study concluded that even if warming was to be limited to 1.5°C, these positive phases would be twice as likely to happen.
The impact on India
Scientists have already predicted that the locust swarms will continue to develop in South Sudan, Uganda, Oman, Pakistan, India, Saudi Arabia and Southern Iran, among other countries, and is likely to get worse in the coming months.
Locust outbreaks have been reported in India, especially in its states of Rajasthan, Gujarat and even Punjab in the past year, continuing into this year. Reports state that the swarms have come into the country from Pakistan and have damaged crops totalling crores of rupees, mainly mustard, castor, cumin and wheat. The main reason for the attacks is extreme weather caused by the IOD.
“The West Indian Ocean, including the Arabian Sea, was warmer than usual during the past two seasons. This is largely due to the IOD, and also due to the rising ocean temperatures associated with global warming. Heavy, prolonged rains over the west coast of India (including Rajasthan) during the latter half of the monsoon— and unusually strong cyclones during the post-monsoon season— may have links with these warm ocean temperatures in the west Indian Ocean region,” Dr Roxy Koll Mathew, senior scientist at IITM Pune, said.
“Another weather phenomenon called the Madden Julian Oscillation (MJO) — a band of eastward moving convective clouds— was also quite active in the Indian Ocean when the IOD was at its peak. Besides, our recent research shows that the rapid warming in the Arabian Sea has resulted in a threefold rise in widespread extreme rains, leading to large-scale floods, along the west coast and parts of central India” Mathew said.
Farmers have complained of the government’s inertia in tackling the problem. One government official was quoted as saying an invasion that began in December 2019 was the biggest locust attack in Gujarat and Rajasthan since 1993-94. While the government is yet to assess the damage, around 9,000 hectares of farmland in both states have been invaded by the swarms.
If these locust outbreaks are not dealt with, the worst-case scenario would be loss of livelihood of one-tenth of the world’s population, according to the FAO.