Dar City to sink in next five decades

Dar es Salaam. Five decades from now sounds like a very long time but scientists say it is the time it will take for coastal flooding to wipe Dar es Salaam off the map, especially Temeke and Kinondoni.

These two districts will be flooded, says the first quantitative estimate of the potential number of people and associated economic assets that are exposed to coastal flooding.

This risk, described as credible, is attributed to the rise of the sea level in future, according to a study by Robert J. Nicholls, a Professor of Coastal Engineering, and PhD Researcher Abiy S. Kebede, both from the University of Southampton.

Almost five million people live in Dar es Salaam—the country’s largest commercial city with a population of over five million and home to about 10 per cent of the population. Most residents here live in poor and unplanned settlements, leaving the city prone to coastal flooding in future.

The city is also characterised by urban sprawl and expanding informal settlements, resulting from increasing population pressure, poor infrastructure and inadequate town planning. All these factors expose Dar es Salaam to disasters resulting from heavy rain.

According to the 2002 census data, most of the unplanned settlements are concentrated in Kinondoni district. Tandale ward has the highest inland population density of about 43,000 people per square kilometre. The researchers note that most of the city’s population growth has taken place along the central and northern part of the coastline, with the majority of the population living in unplanned and informal inland settlements.

The scariest part of the study dubbed “Exposure and vulnerability to climate extremes: population and asset exposure to coastal flooding in Dar es Salaam, Tanzania” is that both natural and man-made defences are compromised by poor urban planning and unplanned human settlements.

Potentially, the scientists point out, millions of people could be exposed to a 100-year coastal flood event by 2070, up from 30,000 people in 2005, while assets such as buildings and businesses that could be damaged due to such an event is estimated to rise from $35 million (2015) to $10 billion (2070).

About eight per cent of Dar es Salaam lies within the low-elevation coastal zone that is below the 10-metre contour lines. In the past weeks, the city has been devastated by heavy rains, destroying the already dilapidated infrastructure and working up a transport crisis for millions of city dwellers.

On Tuesday this week, The Citizen reported that authorities estimate that it could cost upward of Sh44 billion ($27million) to repair the road network.

Last month, Executive Director of the Centre for Sustainable Modern Energy Expertise Estomihi Sawe said that although destructive floods happen after many years, signs that the changing climatic conditions could raise the chances of such calamities recurring more often are already evident—and the authorities should consider planning for the future now. He advised: “It is high time our authorities put in place long-term strategies to save the city from being cut off from the rest of the country and subject the country to loss of lives and a battered economy.”

The study makes it clear that the scenarios investigated provide a wide range of possible futures and associated exposure that indicate the potential worst-case magnitude of any future event that needs to be considered when planning for the future. While climate change is largely attributed to the industrialised nations, the two researchers point out that the city’s growing population and rapid urbanisation represent the most dynamic factors underlying most of the immediate causes of degradation of the natural environment.

In the past few weeks, several scientist groups have tried to show that following the increasingly high greenhouse gas emissions over this century, what was once a one-in-100-years flood experience may now occur more often.

Two groups of scientists quoted by The New York Times reported recently that a large section of the mighty West Antarctica ice sheet has started falling apart and its continued melting appears unstoppable. If the findings hold up, the groups suggest that the melting could destabilise areas neighbouring the ice sheet and a rise in sea level of 10 feet or more may be unavoidable in coming centuries. Scientists have warned that although the rise of the sea is likely to continue to be relatively slow for the rest of the 21st century, in the more distant future it may accelerate markedly, potentially throwing society into crisis.