Climate Change
Researchers believe the pattern of thunderstorms known
as mesoscale convective systems will increase in frequency
as global temperatures rise, as a consequence of increasing
levels of carbon dioxide in the atmosphere, in turn driven by
worldwide use of fossil fuels as sources of energy.
Mesoscale convective systems are big, bad and very cold
columns of thunderous cloud: up to 16km high, covering an
area of 25,000 square kilometres, and with temperatures at
the highest altitude as low as minus 40°C.
Betwe en 1986 and 2005, Burkina Faso registered floods at a
rate of little more than one a year. In the 11 years between
2006 and 2016, it was hit by 55 flood events
Repeated warnings
Climate scientists have been warning for three decades
that global warming will be accompanied by an increase in
“extreme” events: in particular drought, flood, heat wave and
tropical cyclone.
Global warming has already been observed in the Sahel, and
the consequences have not necessarily been bad: overall,
precipitation has increased, and farmers have benefited,
although in a dryland region south of the Sahara where
people have endured a 2,000-year history of periodic
drought, famine remains a constant hazard.
And now, so do massive downpours of rain: the Sahel
storms. British and French scientists examined 35 years of
satellite data and the rain gauges in the region to identify a
rise in extreme daily rainfall totals. They found 85 per cent
of extreme rainfall cases coincided with satellite records of a
passing mesoscale convection system.
They also examined the pattern of temperatures over
the region and found that although the annual average
temperatures have risen, the so-called “wet season”
temperatures have remained steady. That is, locally warmer
conditions alone have not brought more rainfall.
Instead, they blame man-made global warming which has
changed wind and rain conditions, and this will go on
strengthening during this century, “suggesting the Sahel will
experience particularly marked increases in extreme rain,”
they conclude.
“Global warming is expected to produce more intense
storms, but we were shocked to see the speed of changes
taking place in this region of Africa,” said Christopher
Taylor, a meteorologist at the UK’s Centre for Ecology and
Hydrology, who led the study.
His co-author Douglas Parker, professor of meteorology
at the University of Leeds in the UK, said: “African storms
are highly organised meteorological engines, whose currents
extract water from the air to produce torrential rain.
“We have seen these engines becoming more efficient over
recent decades, with resulting increases in the frequency of
hazardous events.”
This story is published with permission from Climate News Network.
Water and Climate Change
Water is the primary medium through which we will
feel the effects of climate change. Water availability is
becoming less predictable in many places, and increased
incidences of flooding
threaten to destroy water
points and sanitation
facilities and contaminate
water sources.
In some regions,
droughts are exacerbating A man serves lentils to a young girl
water scarcity and thereby at a feeding centre in Mogadishu,
negatively impacting
Somalia in 2017 during a severe
people’s health and
drought. UN Photo/Tobin Jones
productivity. Ensuring
that everyone has access to sustainable water and
sanitation services is a critical climate change mitigation
strategy for the years ahead.
Challenges
Higher temperatures and more extreme, less
predictable, weather conditions are projected to affect
availability and distribution of rainfall, snowmelt, river
flows and groundwater,
and further deteriorate
water quality. Low-
income communities,
who are already the most
vulnerable to any threats
to water supply are likely
A piece by street artist Banksy near to be worst affected.
the Oval bridge in Camden, north
More floods and severe
London in view of the UN Climate
droughts are predicted.
Summit in Copenhagen in 2009.
Changes in water
availability will also impact health and food security and
have already proven to trigger refugee dynamics and
political instability.
Opportunities
Water plays a pivotal role in how the world mitigates
and adapts to the effects of climate change. An
integrated view on water, the biosphere and
environmental
flows is required to
devise sustainable
agricultural and
economic systems
that will allow us to
decelerate climate
change, protect
A piece by street artist Banksy near the
us from extremes
Oval bridge in Camden, north London
and to adapt to the
in view of the UN Climate Summit in
unavoidable at the
Copenhagen in 2009
same time.
Africa Water, Sanitation & Hygiene • July - August 2017
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