East Africa's blue economy under threat as temperatures surge

As our plane landed at Abeid Amani Karume International Airport on the tropical island of Zanzibar, we were immediately greeted by the familiar beauty of its palm-fringed shores. What made the experience even more captivating was the sight of the vibrant, historic Stone Town, a true gem that has earned Zanzibar its reputation as a beloved tourist destination.

Yet, alongside this beauty, there was a noticeable shift —  a sweltering, almost oppressive heat that seemed to embrace us at every corner. The air was heavy with humidity, and even the shade under the trees offered little relief from the intense heat. At our hotel, the air conditioner ran nonstop, and in the workshop hall where we spent nearly a week learning about climate change and the ocean, three air conditioners were required to keep the space bearable.

Also read: New report declares 2024 as Kenya’s warmest year on record

Zanzibar, like much of East Africa, has been grappling with rising temperatures. While the island has always boasted a warm tropical climate, in recent years, temperatures have been climbing at an alarming rate—  significantly faster than the global average. While the world has warmed by approximately 1.1°C since pre-industrial times, East Africa has seen temperatures rise by nearly 1.5°C over the same period, making it one of the fastest-warming regions globally.

The Intergovernmental Panel on Climate Change (IPCC) 2021 reports show a rise in extreme heat events across Zanzibar and the wider East African region. According to the World Meteorological Organisation, East Africa has experienced a gradual increase in temperatures over the past century, a trend that has accelerated in recent decades.

Global ocean average

Alarmingly, coastal waters around Zanzibar have seen a rise of nearly 7°C since 1990, with sea temperatures climbing from an average of 31°C in 1990 to a stifling 38°C by 2020. This rate of warming is approximately three times faster than the global ocean average, which has warmed by about 0.13°C per decade since 1900. Air temperatures, too, have been consistently above long-term averages, with heatwaves becoming an increasingly frequent threat.

This escalation in temperatures is not isolated to Zanzibar alone. Neighbouring countries like Kenya, Tanzania, and Uganda are experiencing similar temperature surges as coastal cities and inland areas alike are subjected to the wrath of extreme heat.

As Dr Joyce Kimutai, a climate scientist and a climate attribution researcher at the Kenya Meteorological service and Imperial College in London explains, this trend points to an urgent climate crisis unfolding in East Africa.

"Increasing temperatures are driving more frequent and intense tropical cyclones," Dr Kimutai explains. "These storms are becoming stronger, often reaching Category four and five, and are wreaking havoc across the East African coastline and islands. The combination of high winds, storm surges and heavy rainfall puts both human life and infrastructure at great risk."

One of the most profound impacts of rising temperatures is being felt in the region's critical blue economy sector. Ghaamid Abdulbasat, a climate and biodiversity expert with the International Union for Conservation of Nature, highlights the devastating effects on marine life. "Rising sea temperatures are causing coral reefs to bleach, fish stocks are declining, and coastal communities are struggling to adapt.”

For instance, Pius James, a manager at Mwani Seaweed Company in Paje area of the island, says that over the past few years, they have seen rising sea temperatures, which have significantly impacted seaweed production.

"We've experienced the emergence of diseases such as bacterial and fungal infections that are affecting the productivity of our crops," he adds.

This decline directly impacts the livelihoods of over 25,000 seaweed farmers in Zanzibar, predominantly women, who depend on this crop as their primary source of income. Many families have reported income reductions of 30-40 per cent in recent years as harvests diminish.

Also read: Tapping into the potential of blue carbon ecosystems

In Kenya, the effects of rising ocean temperatures are being felt in seagrass beds. A 2018 study on Kenya's seagrass coverage titled "The thinning green line?" found an average annual loss of 0.85 per cent between 1986 and 2016, with the rate accelerating from 0.29 per cent per year (1986–2000) to 1.59 per cent per year (2000–2016). The Watamu-Malindi region was hit hardest, losing 77 per cent of its seagrass over 30 years, with the loss rate increasing from 0.73 per cent per year (1986–2000) to 4.64 per cent per year (2000–2016).

"Seagrasses play a crucial role in carbon sequestration, reducing coastal erosion and maintaining biodiversity. But as ocean temperatures continue rising, we are seeing a dramatic decline in these ecosystems, which not only disrupts the food chains but also weakens our coastlines against storm surges and high waves," explains Kevin Lunzalu, a marine ecologist and a marine project officer at the East African Wildlife Society.

Experts warn that beyond the ocean, the economic impact of rising temperatures could pose a serious threat to the region's tourism industry, which contributes approximately 8.1 per cent to East Africa's GDP and supports over 3.1 million jobs directly and indirectly.

"As temperatures rise, tourists may begin to choose cooler destinations, and with tourism being a major part of the region's economy, the changing climate could directly affect this sector," explains Mr Abdulbasat.

For coastal communities, the changing climate brings multiple challenges. Fishermen in Zanzibar's Nungwi village report traveling twice as far today to catch half the amount of fish they netted a decade ago. Meanwhile, coastal erosion has forced several communities to relocate inland, abandoning ancestral homes and disrupting traditional ways of life.

But amid these growing challenges, regional and local governments are taking action to mitigate the effects of climate change. In Zanzibar, for instance, the government is prioritising climate resilience through the enhancement of infrastructure and resource management.

"We are focusing on green spaces, water conservation, and improved public transport systems. Additionally, we are collaborating with international organisations to support climate adaptation, including coastal protection and reforestation projects," explains Ilyass Rajab Nassor, head of the Management Division at the Zanzibar Commission for Tourism.

Promising initiatives include the Blue Ventures project in Zanzibar, which has successfully implemented community-led marine conservation efforts, resulting in a 30 per cent increase in local fish catches through sustainable fishing practices and marine protected areas.

Further across East Africa, experts are calling for stronger investments in climate adaptation strategies, particularly in the most vulnerable coastal zones.

"This includes improving coastal zone management, building flood protection infrastructure, upgrading early warning systems and fostering cross-border cooperation in climate monitoring and disaster response," explains Mr Abdulbasat.

Dr Kimutai advocates for more inclusive approaches that involve local communities in climate solutions. "Developing early warning systems and integrating climate information into local development plans will be key in ensuring that communities are prepared for the increasing frequency of extreme weather events.”

But overall, experts unanimously agree on the urgent need for stronger policies to cut carbon emissions. A recent study by World Weather Attribution focusing on East Africa reveals that the region's recent extreme temperatures would have been nearly impossible without human-induced climate change.

"In other words, in a world without global warming, these heat waves simply wouldn't have happened," adds Dr Kimutai.

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