Sea levels are rising around the world. In the past quarter century, on the northeastern African coastline, sea levels have risen by as much as 12cm. The future looks even more worrying.
Some of the more optimistic global climate change projections, which assume a reduction in greenhouse gas emissions, indicate that sea levels could rise to 0.40m by 2100. But if we don’t reduce emissions enough, sea levels could rise to 0.78m by 2100.
This scenario could pan out if countries don’t reduce their carbon emissions. High emissions mean increasing global temperatures, which causes seawater to expand and ice over land to melt – both of which can cause a rise in sea level.
Sea level rise is inevitable. Some countries are already considering — or taking — action. Many parts of the African coastline are an unfortunate exception. These areas are at risk of being left behind in the adaption trend.
I found out this through my own research in which I assessed the impact of sea level rise, including damage costs and the number of people that could be flooded in the future around the African coast.
All coastal nations will be affected — that’s a total of 50 African countries and surrounding islands. But those that are very low-lying risk being hit the hardest. They face increased flooding, erosion, groundwater salinisation on agricultural land, as well as reduced tourism and economic activity.
Despite these risks, limited action is being taken. Many African countries have more immediate issues and are understandably less concerned by something that may not affect them for many decades.
In our research, we found that the impact of rising sea levels could be reduced by adapting the coastline and infrastructure. This includes building dikes to reduce flooding, and adding sand to beaches to reduce erosion. This could cut damage costs in half by 2100.
But these measures require substantial investment. It would require billions of dollars to provide better protection today. Costs would continue to increase in the future as sea levels rise and populations and cities grow.
The number of people affected is projected to be high, unless they adapt. This is particularly true in countries such as Egypt or Mozambique whose populated coastlines are low-lying or prone to storms.
But many African countries don’t have the available funds and have more immediate poverty challenges, so they need to look to international climate funds to help. Although the costs of protection are high, the costs of inaction are even greater.
Another challenge in addressing future sea level rise is population growth.
In 2000, 54.2 million people on the continent lived in low-elevation coastal zones — typically land which is less than 10m above sea level. Experts project that, by 2030, this number could have doubled to between 109 and 118 million people.
Currently, 85 per cent of those living in low-elevation coastal zones live in urban areas. Planning, particularly for urban areas where populations are expected to grow the most, is therefore needed.