With climate threats high across Africa, COVID-19 restrictions may prevent people from moving as a survival strategy.

Movement is a critical resilience strategy for communities affected by climate change. Climate threats are currently high across much of Africa, with floods, droughts and the biggest locust outbreak in generations. Increased restrictions on movement due to COVID-19 may intensify the effects and put people at even more risk.

Major desert locust outbreaks across East Africa are threatening food security in at least eight countries and are projected to continue spreading. It is the worst infestation in 70 years for Kenya and 25 years for Somalia and Ethiopia.

The West Indian Ocean has been warmer than usual in the past two years due to rising ocean temperatures and the Indian Ocean Dipole. After years of drought, this has led to exceptionally heavy rains in the countries near this ocean, namely Djibouti, Ethiopia, Kenya, Uganda, Tanzania, Somalia and South Sudan. These rains are ideal breeding conditions for desert locusts.

A desert locust swarm can travel 150 km in a day and a small swarm can consume the equivalent of food for 35 000 people in one day. The first wave in early 2020 saw swarms the size of cities. The second wave, which started in early April, compounds the damage already done.

Now the region is experiencing its highest rainfall in 40 years. In addition to major flooding and landslides, this second and even bigger wave of locusts is predicted to mature in June. This could lead to considerable crop damage as farmers begin their main harvest.

The African Union has labelled the infestation 'an unprecedented threat to food and economic security'. It warns that the locusts could spread to western and northern regions, becoming a continental plague. Almost 25 million people in the affected area already face severe food insecurity. This region is also home to one of the world's largest populations of displaced people -- almost 4.4 million refugees and over nine million internally displaced people.

While the Indian Ocean Dipole has pushed warm waters to East Africa, a corresponding subtropical Indian Ocean Dipole has pushed cold water south of Madagascar and supressed rains across Southern Africa. Since late 2018, Southern Africa has been subjected to severe drought due to below average and erratic rainfalls and extreme temperatures. Crops and livestock production have been severely impacted, affecting over 18 million people.

In Zimbabwe, the drought has decimated maize and other crop production. This is exacerbated by political and macro-economic mismanagement. The country is facing its worst hunger crisis with almost half the population (7.7 million) in rural and urban settings urgently needing humanitarian aid.

Historically, millions of Zimbabweans have fled into neighbouring Botswana and South Africa during difficult times to seek work or get basic supplies. These borders have been closed under COVID-19 restrictions. Formal border closures or a lack of safe and regular passage opportunities often drive irregular and unsafe movement, particularly in desperate situations.

S­­low onset climate effects, including drought, desertification and salinisation (increasing salt content in soil), are disrupting crops more frequently and diminishing agricultural returns for many farmers. Being able to move allows individuals and families to diversify income, spread household risk and send remittances home. But that requires resources.

In rural and farming communities, people are most likely to move the shortest possible distance to a location where they can find work. It's most often temporary and circular. Families are unlikely to abandon a farm due to a season of poor crops. They're more likely to send some members to seek work and remit money to supplement farming income. These members often return once conditions improve.

Sudden onset climate change disasters such as extreme temperatures, landslides, droughts, wildfires, floods or hurricanes are the top drivers of internal migration. Reportedly 24.9 million people were newly displaced by disasters in 2019, compared to 8.5 million by conflict and armed violence. And 195% more Africans were affected by extreme weather events in 2019 than in 2018.

In sudden onset climate disasters, people mostly flee to the nearest safe location or where there's aid. People unable to move away from affected areas can become trapped and left extremely vulnerable. Often the groups most susceptible to climate-related threats, such as poor subsistence farmers, are the least able to move away.

While migration offers a positive adaptation strategy to mitigate the impacts of climate change for those who can achieve it, immobility can increase vulnerabilities and risks. COVID-19 has rendered people more immobile than usual.

As of 7 May, 219 countries -- including all African countries -- had issued over 60 771 domestic and international movement restrictions. In some cases, measures to contain the coronavirus are opposite to those needed for climate change responses. In some cases, governments have refused to open evacuation centres due to COVID-19 concerns.

Safe passage for people threatened by climate change must be facilitated where needed. People fleeing disasters, in particular, must be enabled to move away from danger as safely as possible, including using health screenings to minimise COVID-19 transmission.

The impacts of both sudden and slow onset climate change are likely to converge with the economic and social fallouts of COVID-19. Urban economic slowdowns, reduced remittances and government support packages due to lost revenues will create severe hardship across Africa. Movement restrictions meant to protect people could end up inhibiting their ability to respond or push them towards irregular or dangerous means.

If freedom to travel remains limited during the pandemic, people will be even more vulnerable than projected, including while travelling to access life-saving help. Aid agencies, including the United Nations' Food and Agriculture Organization and World Food Programme, recognise these complex threats. They've recently increased their appeals to protect food security and livelihoods. With COVID-19 dominating international attention, it's more urgent than ever that these threats are recognised and these appeals fully funded.