What has the Indian Ocean got to do with Locusts

Locust Enter Uganda

As Uganda battles a bellicose swarm of plant-scavenging locusts, questions must surely be asked. Sadly, on a very disturbing note, that is, the actual topic that ought to be taking centre, remains mostly shelved. Shall we finally see the real discussion happening in Uganda, Djibouti, Ethiopia, Kenya, Tanzania, Somalia and South Sudan? Could it maybe gain more prominence through the Intergovernmental Authority on Development (IGAD), a body that brings most of these countries together? “But why not just talk killing locusts?” you might be wondering.

In the thick of this, an interview with Richard Munang, the United Nations Environment Programme expert on climate and Africa, on the organisation’s site stood out. He blamed climate change for the locust invasion. “During quiet periods—known as recessions—desert locusts are usually restricted to the semi-arid and arid deserts of Africa, the Near East and South-West Asia that receive less than 200 mm of rain annually. In normal conditions, locust numbers decrease either by natural mortality or through migration,” he said. But something happened, he calls it the Indian Ocean dipole, it brought rain, lots of it, and now the locusts are here. What is the Indian Ocean Dipole anyway?

The Indian Ocean Dipole

To climate enthusiasts, the Indian Ocean dipole is no strange discourse, but not to the ordinary man. In attempts to explain the extreme weather conditions that have since led to flooding and drought, the BBC explored the topic more. It refers to it as the difference in sea-surface temperatures in opposite parts of the Indian Ocean. They further explain that temperatures in the eastern part of the ocean oscillate between warm and cold compared with the western part, cycling through phases referred to as “positive”, “neutral” and “negative”.

Last year, the dipole’s positive phase brought with it warmer sea temperatures in the western Indian Ocean region, and more rains in the east. This they say explains why the Eastern part of Africa had lots of rain while South East Asia and Australia battled excruciatingly hot sun that would later fuel raving bush fires in Australia.

The UN’s Munang was onto something here, right? He maintains that while studies have linked a hotter climate to more damaging locust swarms, wet weather is also known to favour multiplication of locusts. The Horn of Africa has received heavy rainfall from October to December 2019 with up to 400% above normal rainfall amount recorded, this is not a good thing. “These abnormal rains were caused by the Indian Ocean dipole, a phenomenon accentuated by climate change,” he confirms. Sadly, researchers say the effects of the dipole could get worse because of this very climate change.

Speaking to the UK’s The Guardian, Caroline Ummenhofer, a scientist at Woods Hole Oceanographic Institution in Massachusetts who has been a key figure in efforts to understand the importance of the dipole, said unique factors were at play in the Indian Ocean compared with other tropical regions.

While ocean currents and winds in the Atlantic and Pacific can disperse heating water, the large Asian landmass to the north of the Indian Ocean makes it particularly susceptible to retaining heat. “It’s quite different to the tropical Atlantic and tropical Pacific events. There you have steady easterly trade winds. In the Indian Ocean that’s not the case,” Ummenhofer said. Like Munang, she also believes it boils down to climate change. So what exactly is climate change?

The National Geographical channel simply defines climate change as a long-term shift in global or regional climate patterns, a thing researchers argue is only getting worse if not treated with urgency. But also, two words are thrown around every time Climate is discussed, that is global warming.

Global Warming

We decided to seek out the Oxford Dictionary for this one: Global warming is a gradual increase in the overall temperature of the earth’s atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide. But what does this even mean?

According to America’s National Resource Defence Council (NRDC), over the past 50 years, the average global temperature has increased at the fastest rate in recorded history. Which is basically a longer phrase for global warming. The Science Journal explains that global warming occurs when carbon dioxide (CO2) and other air pollutants and greenhouse gases collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface.

Normally, this radiation would escape into space—but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. Or what NRDC refers to as the greenhouse effect. One of the biggest causes of pollution researchers argue is the making of electricity, industry and transportation. Made even worse by the intense deforestation, as the trees that help absorb some of this carbon dioxide have dwindled. So what needs to be done?

Way Forward

Right this minute, the UN worries the insects will devour crops meant for humans to eat. If East Africa alone has a mammoth 19 million people estimated to be starving, imagine the damage in years to come? These locusts can travel up to 150 kilometres (93 miles) in 24 hours and an adult insect eats its own body weight in food each day. The UN fears the number of insects could multiply 500 times by June this year. Imagine that!

In fact, whilst speaking to the Associated Press, Keith Cressman, a senior locust forecasting officer with the FAO said that in a few weeks the young locusts will shed their skin. “It takes a few days to warm up their wings,” he said. Some test flights follow and they’re on the move. The locusts at that stage are bright pink and in their most voracious state, like “very hungry teenagers,” Cressman said.

While the UN’s environmental arm acknowledges that climate change is a global phenomenon, it reckons that Africa stands out for its vulnerability. This is driven primarily by the prevailing low levels of socioeconomic development and the fact that a large chunk of her population relies on Agriculture. Wondering how this can be stopped, here’s a start: Plant a tree, dispose of all the harsh gas-emitting devices like the old cars and electrical appliances.


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