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Helping coastal areas adapt to climate change now is vital to keep costs down in the future
Climate change is no longer an abstract issue, thanks to the latest authoritative assessments from the Intergovernmental Panel on Climate Change (IPCC). And the potential impacts of sea-level rise caused by warmer global temperatures are becoming clearer.
Up to 600 million coastal people around the globe could face devastating consequences from rising seas. Some small island states are at risk of disappearing. Coastal cities and towns could be washed away. Given the scale of the threat, Africa urgently needs to prepare.
The Fifth Assessment Report of the Intergovernmental Panel on Climate Change states that, even with large reductions in emissions, sea-level rise can be expected to reach 28-61cm by 2100. Adaptation to climate change and recovery costs associated with flood damage could reduce global GDP by up to 10 percent by 2100 if adaptation measures are not implemented. This is shown in a recent study, Coastal flood damage and adaptation costs under 21st century sea-level rise, by a group of researchers from Britain’s University of Southampton.
How well coastal communities implement adaptation measures is found to be the most important factor in trying to limit the costs of sea-level rise. In other words, the budgetary choice is clear, and acting now will save money in the coming decade.
Tropical regions, including large parts of the African continent, are likely to experience sea-level rise that is higher than the average. According to the Africa Adaptation Gap Report, Africa faces huge financial challenges in adapting to climate change. The report spells out the costs faced by the continent if governments fail to close the "emissions gap" to keep warming below 2 degrees Celsius.
With a temperature increase of 3.5 to 4 degrees, Africa's coastline is expected to experience sea-level rise that is 10 percent higher than the rest of the world, with several countries particularly hard hit. This could affect maritime activities and reverse the economic gains that have been achieved over the past decades.
Fishery-related jobs will be reduced by 50 percent by 2050. With a sea-level rise of 70 cm by 2070, Dar es Salaam in Tanzania risks losing $10 billion worth of assets (or 10 percent of the port city’s GDP). Mombasa in Kenya could lose $15 billion in assets, and 117,000 people will be exposed to risks associated with sea-level rise by 2080.
Globally, 40 percent of the population lives within 100km of the coast. In Africa, 36 countries are located along the coastline, which spans about 26,000km. Sea-level rise is expected to be the most severe challenge, requiring widespread adaptation action along coastal sub-Saharan Africa. As Africa’s population is likely to reach close to 2 billion by 2050, more people will be exposed to the consequences. Adapting to this climate risk is an urgent imperative.
Harnessing the potential of ecosystem services could be the answer. Coastal ecosystems, and in particular coral reefs, provide over 500 million people worldwide with services. At the same time these ecosystems are highly vulnerable to climatic changes.
Coastal ecosystems, which also include mangroves, are crucial in protecting shores against storm surges, large waves and extreme weather events. The Economics of Ecosystems and Biodiversity (TEEB) initiative found that coral reefs also generate incomes of up to $1.25 million per hectare every year. Yet up to three quarters of corals reefs are under threat due to local and global pressures, according to a 2011 study.
The costs of one-time adaptation action - measured as building dikes for simplification - implemented in a low sea-level rise scenario will be high to begin with and then level off, the Southampton study found.
The Africa Adaptation Gap Report emphasised that implementing adaptation action at an early stage would significantly reduce the later costs of damage associated with climate-related crises. The report showed that total adaptation costs in Africa could reach approximately $350 billion annually by 2070, should a 2-degree temperature rise be significantly exceeded.
In fact, many of the ecosystem-based practices and technologies we need are already in use in Africa and elsewhere. But what are now mainly isolated success stories must be expanded, to make them the rule rather than the exception.
In Mozambique, for example, an investment of $120 per person in rehabilitating mangroves and reducing overfishing by constructing crab cages and fish ponds to supplement catches provided food security for 490 people. With relatively small inputs, this kind of adaptation can protect local ecosystems from climate stresses and improve community well-being.
Investments in adaptation measures that increase coastal resilience are necessary to protect coastal areas from the impacts of rising sea levels and a harsher climate. Such investments are not only good value for money, but will enhance our ability to adapt sustainably in the longer term.
Richard Munang is Africa Regional Climate Change Programme Co-ordinator with the United Nations Environment Programme (UNEP). He tweets as @MTingem. Julie Hval is an officer with the Climate Change Programme in UNEP’s Regional Office for Africa.
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