The Guardian - Kaamil Ahmed
Experts fear swarms like those seen in Africa will become more common as tropical storms create favourable breeding conditions
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| A man tries to catch locusts as they swarm over Sana’a in July 2019. The insects have since reached east Africa, threatening the food security of 25 million people. Photograph: Mohammed Huwais/AFP/Getty Images |
The
locust crisis that has now reached 10 countries could carry on to endanger millions more people, forecasters have said.
Climate change
created unprecedented conditions for the locusts to breed in the
usually barren desert of the Arabian gulf, according to experts, and the
insects were then able to spread through Yemen, where civil war has
devastated the ability to control locust populations.
It was
Cyclone Mekunu,
which struck in 2018, that allowed several generations of desert
locusts the moist sand and vegetation to thrive in the desert between
Saudi Arabia, Yemen and Oman known as the Empty Quarter, breeding and
forming into crop-devouring swarms, said Keith Cressman, locust
forecasting expert for the UN’s Food and Agriculture Organization (FAO).
“That’s
fine, that’s quite good in itself, but just about when those conditions
are drying out and the breeding is coming to an end, a second cyclone
came to the area,” he said.
“That allowed the conditions to continue to be favourable and another
generation of breeding, so instead of increasing 400-fold, they
increased 8,000-fold.
“Usually a cyclone brings favourable conditions for about six months
and then the habitat dries out, and so it’s not favourable for
reproduction and they die and migrate.”
The amount of cyclones in the
area seem to be increasing, said Cressman, making it likely that locust
swarms will also become more common.
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| A man attempts to fend off a swarm of desert locusts at a ranch near the town of Nanyuki, in Kenya’s Laikipia county. Photograph: Baz Ratner/Reuters |
The FAO has warned that the food
security of 25 million people could be endangered by the locusts, which
according to the agency’s
locust monitoring service
have been spotted in at least 10 countries over recent months.
One
swarm recently reported in Kenya covered an area the size of Luxembourg.
The organisation has requested
$140m
(£120m) to help fight the ongoing breeding of the insects, predicting
that a continuation through late March and April could see the existing
number of locusts grow by 400 times by June.
The current crisis is considered the worst in decades, and there are fears it could last longer than previous locust outbreaks.
Alongside the climate emergency impact, the war in
Yemen is a key factor.
Cressman said Yemen is a “frontline” country for locusts, with the
insects typically present throughout the year. But its once effective
locust programme no longer has the same impact in cities where control
is now divided between the government and Houthi rebels.
The head of the locust programme, Adel al-Shaibani, is based in the Houthi-controlled capital, Sana’a.
“Before the war we had a good ability to reach anywhere in Yemen,” he
said. “In current times we’re just able to cover the Red Sea coastal
areas – but not all – and some areas in the interior.”
He explained that there were two separate locust control centres in
Yemen but neither was able to combat the outbreak effectively alone.
The Sana’a-based centre carried out control operations wherever they
could in 2018, but they have been underfunded and have lost some of
their vehicles.
“In spite of all our hard efforts, some areas
remained out of control due to security reasons near the border with
Saudi Arabia. The desert locust outbreak occurred and some swarms formed
and moved to other areas,” said Shaibani.
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| A young desert locust without wings is seen on a stalk near Geerisa town, in Somaliland’s Lughaya district. Photograph: Daniel Irungu/EPA |
By late 2019, the locusts had moved into the Horn of
Africa,
finding favourable conditions when an unseasonaal cyclone hit Somalia
in December. This extended breeding time and allowed them to spread to
areas authorities could not control because of the country’s security
problems.
“This crisis could be quite long because of the Yemeni and Somali
areas that cannot control the populations,” said Cyril Piou, an expert
with the French Agricultural Research Centre for International
Development.
He said that in previous decades locust outbreaks had
only lasted roughly two years but, without preventive systems, they
will last longer, happen more frequently and spread further.
“We are all linked in some way, what is happening somewhere else affects us all,” he said.
The
last comparable locust outbreak was in the late 1940s and 50s, but
Cressman said that was in a time when monitoring and reporting was a
slow, cumbersome process and chemical pesticides were readily available
for control operations.
Historically, the Arabian Gulf has very few cyclones. But the past decade has brought a significant increase thanks to the
Indian Ocean dipole, a phenomenon linked to flooding in the western Indian Ocean, dry weather in the east and wildfires in Australia.
Cressman, part of whose job involves looking at historical conditions
to understand current developments, said the climate’s behavioural
changes made that difficult.
“This analogous forecasting methodology used to work pretty good up
until five years ago, and it’s just not working very well any more at
all because of the rainfall, the timing, the distribution. It’s very
different,” he said.
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