Fatal floods in Africa

Dec 16, 2010 By Phillip F. Schewe
The yellow-to-red areas on this map of Africa show population growth over the period 1960-2000. The location of floods over the period 1985 to 2009 are denoted by dots and deadly floods by black circles. Credit: Courtesy Giuliano Di Baldassarre

When natural disasters claim human lives, it's important to determine whether the problem is geophysical or cultural. A new study shows that the large upswing in flood deaths in Africa over past decades is chiefly the result of population settlement patterns, and is not a consequence of changing climate.

Floods displaced 2.5 million people in Africa in 2009 and more than a million in 2007. Overall African flood fatalities increased by a factor of ten from 1950 to 2009. Over 15,000 people died during the decade 2000-2009.

The in areas prone to flood damage also increased by a factor of ten over the same period.

Why do people live in places that flood? Historically people are drawn to riverbanks and coastlines for a number of reasons: jobs, irrigation water and easy transport.

Six scientists made a detailed study of the water discharge of African rivers over the years from 1900 to 2000 to see if the rivers themselves had changed, perhaps due to . They found that the amount of water coursing through the rivers hasn't changed that much.

Despite a tenfold increase in flood deaths, the consistent and the tenfold increase in the population settled in flood-risk areas suggested to the new study's authors that the problem is chiefly one of human settlement patterns .

"The details of increasing flood risk in Africa were critically investigated by means of a multidisciplinary approach that combined and climate signals," said Giuliano Di Baldassarre, one of the researchers. "To our knowledge, previous scientific studies investigated these issues separately." Di Baldassarre works in the Department of Hydroinformatics and Knowledge Management in the UNESCO office in Delft, Netherlands.

Having diagnosed the problem at the heart of African flood fatalities, the researchers have sought a remedy. Of course discouraging settlement in the risky areas is a start. But getting people to refrain from living near water is difficult. One way of lowering risk is to install a better warning system based on satellite measurements of rainfall and, in some cases, networks of cell phone alerts.

The new study, which appeared in November in the journal Geophysical Research Letters, points to a successful flood-fatality mitigation scheme used in India. There a storm in 1977 left 20,000 dead from flooding. After a better flood warning system was put in place, a comparably-sized storm in 1996 resulted in 1,000 fatalities, while another in 2005 left only 27 dead.

Roger Pielke, an environmental scientist at the University of Colorado in Boulder, said that the new study helps to explain the rise in flood fatalities in Africa and other developing countries around the world. The task now is to implement the needed remedies.

"Perhaps the greatest value of this paper is to indicate that there is a dubious basis for claims that human-caused climate change is leading to increased flood losses in Africa," said Pielke. "This finding is consistent with the broader literature on climate and losses. Those campaigning for action on emissions reduction should note that there are far better justifications for action than invoking disasters in poor countries."

That is not to say that some consequences of climate change won't pose dangers to people who live near water; rising sea level is one such danger. But based on this study, scientists seem assured that climate change is not responsible for increased African flooding fatalities.

Explore further: Mexico's Volcano of Fire blows huge ash cloud

Source: Inside Science News Service

4.5 /5 (4 votes)
add to favorites email to friend print save as pdf

Related Stories

Images from space reveal ground-level flood threat

Jun 15, 2010

(PhysOrg.com) -- Satellite imagery captured hundreds of miles from the Earth's surface is being used to analyse the flood risks of some of the world's largest regions, using data that researchers hope could become freely ...

Using buildings for flood protection

Sep 07, 2010

Buildings, car parks and roads could, alongside their "regular" functions, have a role to play in protecting the rest of the city from flooding. According to researcher Bianca Stalenberg, this concept could be very useful ...

Global warming could flood Florida coasts

Apr 23, 2008

Scientists studying the consequences of global warming in south Florida say rising sea levels could flood coastal cities and damage fresh water supplies.

Managing Pacific Northwest dams for a changing climate

Jan 21, 2010

Civil engineers at the University of Washington and the U.S. Army Corps of Engineers' Seattle office have taken a first look at how dams in the Columbia River basin, the nation's largest hydropower system, ...

Growth versus global warming

Oct 12, 2009

(PhysOrg.com) -- Houses on stilts, small scale energy generation and recycling our dishwater are just some of the measures that are being proposed to prepare our cities for the effects of global warming.

Recommended for you

Erosion may trigger earthquakes

Nov 21, 2014

Researchers from laboratories at Géosciences Rennes (CNRS/Université de Rennes 1), Géosciences Montpellier (CNRS/Université de Montpellier 2) and Institut de Physique du Globe de Paris (CNRS/IPGP/Université Paris Diderot), ...

Strong undersea earthquake hits eastern Indonesia

Nov 21, 2014

A strong undersea earthquake hit off the coast of eastern Indonesia on Friday, but there were no immediate reports of injuries or serious damage and officials said it was unlikely to trigger a tsunami.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

mikiwud
1 / 5 (11) Dec 17, 2010
Well said. Sense at last. This could apply to most natural disasters worldwide.
As for sea level rise, it has been rising since the end of the last ice age. Mankind naturaly settled in coastal areas without realising this. Result as now expected. If more people stand on railway tracks, more die. Not because the train timetable has changed.
Mivoat
4 / 5 (2) Dec 29, 2010
That's right - sea level was rising by 1m every 20 years at one point (14,000 years ago), but it's been unsually stable for the past 6000 years, which is why so many ancient settlements built at sea level are still inhabited - London UK for example, where I live today. So the current rise of 3mm / year is a big change from that, isn't it?
Did you know the fossil fuel industry is offering good money to people who seek to misinform? How come nearly ALL climate scientists agree that the climate is changing at least in part due to anthropogenic influence. Is it just an elaborate conspiracy to defraud us all in favour of their research budgets? What if it's not and a big problem is coming in future decades?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.