Tuesday, December 20, 2011

Africans Must Adapt to Drought in Warming World: Report

(suggests fewer inflexible big dams, more rainwater harvesting
structures, among other things)

Africans Must Adapt to Drought in Warming World: Report
by Ker Than

For National Geographic News

Climate change will call for more flexible solutions to water
A new report cautions African countries to look beyond dams (like this
one in Zimbabwe) to deal with water supply issues for an uncertain
Photograph from Images of Africa Photobank/Alamy


Published December 16, 2011

Flexible farming methods and the ability to quickly change tactics
to deal with unpredictable swings in rainfall will be vital if African
nations are to survive climate change in the coming decades,
scientists say.

"Adaptability I think will be the key," said Mark Mulligan, a
geographer at King's College London in the United Kingdom.
"There's the assumption that we know what the future will be like. We
do�more or less�for temperature, but we really don't for rainfall," he

Global warming is expected to raise temperatures around the globe in
the coming decades. Perhaps less intuitively, it will also increase
rainfall in other parts of the world because as the temperature goes
up, evaporation speeds up, and the air's ability to retain moisture

More evaporation creates a hydrological cycle that is turbocharged
with energy, leading to more rainfall. However, the geographical
distribution of rainfall will change in a warmer world, greening some
current arid zones and triggering droughts in other areas such as the
American southwest.

See the global impact of your water footprint >>

Click to start interactive >>

Affecting Africa

According to a five-year global research project conducted on behalf
of the Consultative Group on International Agricultural Research
(CGIAR), climate change is expected to lead to unpredictable changes
in rainfall patterns in most African river basins.

This could present opportunities for improved agriculture in some dry
regions that get wetter, or�if farmers are not well prepared�could
lead to less food production and increased poverty as agriculture
struggles to adapt.

"Climate change introduces a new element of uncertainty precisely when
governments and donors are starting to have more open discussions
about sharing water resources and to consider long-term investments in
boosting food production," Alain Vidal, director of the CGIAR's
Challenge Program on Water and Food (CPWF), said in a statement.

"To help prevent this uncertainty from undermining key agreements and
commitments, researchers must build a reliable basis for decisions,
which takes into account the variable impacts of climate change on
river basins," Vidal said.

(Related: "India and Pakistan at Odds Over Shrinking Indus River")

To counter such uncertainty, nations must remain nimble and provide an
enabling environment for their farmers to adapt to a highly uncertain
and geographically variable �changescape,� said Mulligan, who was the
lead author of a report published in January in the journal Water
International that detailed the CGIAR findings.

"The key is to be thinking about flexible arrangements that are fine-
tuned to local geographical conditions and that can change quickly and
effectively as the future unfolds," Mulligan said.

"Because we've had 10,000 years of [climate] stability, we've grown
accustomed to assuming that things don't change and so we now support
very high populations that are dependent on sophisticated
agricultures, markets and infrastructures that may not adapt well to
the period of environmental instability that is ahead of us," he said.

"Bottom up" Solutions

For example, large dams that retain water to supply urban areas, for
irrigation projects, and to generate hydropower�of which there are at
least 36,000 around the world�are usually designed on the basis of
historical river flow data that climate scientists warn could become
obsolete in a warming world where river courses can change.

Because large dams are significant and long-term investments they
cannot easily be adapted to respond to the implications of changing
climate, Mulligan said.

A more flexible solution, he argues, is rainwater harvesting: the
construction of a series of small, farm-scale rainwater harvesting
schemes, or "micro-dams,� that capture rainfall for agricultural use
near the point at which it will be used rather than trapping it at a
single large dam and then pumping it elsewhere.

(Related: "See Spectacular Video of a Historic Dam Removal")

Also, because the pattern of rainfall change across Africa is
essentially unpredictable, CGIAR advocates a bottom-up approach to
adaptation, in which solutions are highly specific to local
geographical conditions rather than being defined on the basis of
regional or national-scale generalities.

The role of African governments, Mulligan said, will be to facilitate
locally driven adaptation and to stay out of the way of sustainable

"The impact of climate change on water and food security will be
different in different parts of a river basin, even on different sides
of a hill," he added.

"So the real adaptation will have to come from the farmers up. They'll
be able to react in a way that is specific to their specific
environment and needs."

You received this message as a subscriber on the list: africa@list.internationalrivers.org

To be removed from the list, please visit:

No comments:

Post a Comment