*Perilous Times and Global Warming
AFRICA: La Niņa: Worst is yet to come, warn climatologists*
01 Oct 2007 16:38:35 GMT
Source: IRIN
JOHANNESBURG, 1 October 2007 (IRIN) - Eastern Africa could face dry
conditions early next year, with the possibility of seasonal rains being
delayed by the effects of a climate phenomenon called La Niņa,
climatologists say.
"The second rainy season starts now for the Horn of Africa and Eastern
Africa - we expect the rains to be near normal over much of the Greater
Horn of Africa," said Bwango Apuuli, deputy director of the
Nairobi-based Climate Prediction and Application Centre (ICPAC) of the
Inter-Governmental Authority on Development (IGAD), the regional grouping.
"There is a fear that La Niņa could have a delayed impact on the rainy
season, which starts in March 2008; the worst may be yet to come.
National Meteorological and Hydrological Services of the region will be
providing regular updates as the phenomenon develops," Apuuli said.
La Niņa is characterised by unusually cold ocean temperatures in the
eastern equatorial Pacific Ocean, recorded every three to four years,
which cause a ripple effect felt across the globe, making wet regions
wetter and dry ones drier.
El Niņo is characterised by unusually warm ocean temperatures in the
equatorial Pacific. The system oscillates between warm El Niņo and
neutral or cold La Niņa conditions every three to four years on average.
Both phenomena result from interaction between the surface of the ocean
and the atmosphere in the tropical Pacific Ocean, according to the US
government's National Oceanic and Atmospheric Administration. "Changes
in the ocean impact the atmosphere and climate patterns around the
globe. In turn, changes in the atmosphere impact the ocean temperatures
and currents."
La Niņa has already prompted some of the most widespread rain recorded
in Africa since the turn of the 1900s, according to Omar Baddour, head
of the World Climate Data and Monitoring Programme at the UN's World
Meteorological Organisation (WMO).
More than a million people have been affected by flooding in over 20
African countries stretching in an arc across sub-Saharan Africa from
Mauritania to Kenya. La Niņa's impact usually lasts for nine to 12
months and is expected to peak in December 2007/January 2008.
According to Baddour, La Niņa usually brings above normal rains to the
Sahel, but the rainbelt has been broadened this year by the combination
of warmer conditions in the Indian Ocean. "In the East African
countries, particularly Kenya, Somalia and parts of Tanzania and Uganda,
La Niņa could influence the short rainy season in
October-November-December, in the way where less rain than average could
occur."
Climate change
Apuuli pointed out that La Niņa's impact has been more intense than the
last event recorded in 2005/06 in Africa, and although it was difficult
to attribute it all to global warming, "there are links".
WMO's Baddour, who has been studying the impact of the phenomenon on
western Africa since the 1990s, said, "There is no statistically
significant trend in the strength of the La Niņa event itself as an
ocean-related phenomenon.
"Scientists project that global warming would increase the occurrence
and intensity of extreme weather events. In other terms, global warming
could intensify/amplify the existing natural climate variability and its
associated weather phenomena."
The floods have affected very large areas across the continent but, in
terms of intensity, other "devastating flooding" in recent times was
recorded in Mozambique in February 2000, in the Sahel summer flooding of
1998 and 1999, and again in 2005 in western part of Sahel, including
Senegal, Baddour said.
"Put together, these events are the most devastating flooding recorded
in sub-Saharan Africa since many decades."
jk/he
|
