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Date: Sun, 02 Dec 2007 13:10:38 -0500
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Subject: Africa: Climate Change Impact Report
Africa: Climate Change Impact Report
AfricaFocus Bulletin
Dec 2, 2007 (071202)
(Reposted from sources cited below)
Editor's Note
"Climate disasters are heavily concentrated in poor countries. Some
262 million people were affected by climate disasters annually from
2000 to 2004, over 98 percent of them in the developing world. ...
In [rich] countries one in 1,500 people was affected by climate
disaster. The comparable figure for developing countries was one in
19." - UNDP Human Development Report
This global inequality cited by the UNDP report (excerpted in
another AfricaFocus Bulletin sent out today). is echoed in the
extensively documented Africa chapter of the latest report from the
Intergovernmental Panel on Climate Change (IPCC), excerpted below
and available in full at http://www.ipcc.ch/ipccreports/ar4-wg2.htm
Both reports were released last month in time for the UN Climate
Change Conference, scheduled for Bali, Indonesia, 3-14 December
2007. The climate change crisis, both reports stress, is not just
an issue for the future. The changes are already increasing risks to survival in areas and population
groups that are particularly vulnerable.
The changes include dramatically visible ones, such as the rapid
drop in the snow and ice cover on the summit of Mt. Kilimanjaro, as
well as others with effects revealed by scientific studies.
See http://svs.gsfc.nasa.gov/stories/kilimanjaro_20021216/ for
photos of Mt. Kilimanjaro, and the extensive documentation in the
IPCC chapter on a wide range of effects. Both reports stress the need not only to slow climate change
but only to prepare for the effects that are already visible and certain to increase.
Previous AfricaFocus Bulletins on climate change issues include:
Africa: Neglecting Agriculture, 2
http://www.africafocus.org/docs07/ag0710b.php
Sahel: Beyond Any Drought?
http://www.africafocus.org/docs07/sah0709.php
Africa: Up in Smoke?
http://www.africafocus.org/docs06/clim0611.php
Africa: Economics of Climate Change
http://www.africafocus.org/docs06/ster0611.php
Africa: Environmental Threats/Opportunities
http://www.africafocus.org/docs06/unep0609.php
Africa: Africa's Lakes
http://www.africafocus.org/docs06/lake0609.php
East Africa: Dams and Lake Victoria
http://www.africafocus.org/docs06/vic0602.php
+++++++++++++++++++++++++++++++++++++++++++++++++
"No Easy Victories" Conversation and Celebration
Washington, DC, Busboys & Poets, December 8, 2007, 5:30 - 7 p.m.
Sponsored by Busboys & Poets, TransAfrica Forum, AFSC Africa
Program, Africa World Press, and the editors of No Easy Victories.
.
For more details:
http://www.noeasyvictories.org/nev_events.php
To read excerpts or to order book:
http://www.noeasyvictories.org
++++++++++++++++++++++end editor's note+++++++++++++++++++++++
Climate Change 2007: Impacts, Adaptation and Vulnerability
Intergovernmental Panel on Climate Change
http://www.ipcc.ch/ipccreports/ar4-wg2.htm
9 Africa
This chapter should be cited as:
Boko, M., I. Niang, A. Nyong, C. Vogel, A. Githeko, M. Medany, B.
Osman-Elasha, R. Tabo and P. Yanda, 2007: Africa. Climate Change
2007: Impacts, Adaptation and Vulnerability. Contribution of
Working Group II to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change, M.L. Parry, O.F.
Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson,
Eds., Cambridge University Press, Cambridge UK, 433-467.
Executive summary
* Africa is one of the most vulnerable continents to climate change
and climate variability, a situation aggravated by the interaction
of 'multiple stresses', occurring at various levels, and low
adaptive capacity (high confidence).
Africa's major economic sectors are vulnerable to current climate
sensitivity, with huge economic impacts, and this vulnerability is
exacerbated by existing developmental challenges such as endemic
poverty, complex governance and institutional dimensions; limited
access to capital, including markets, infrastructure and
technology; ecosystem degradation; and complex disasters and
conflicts. These in turn have contributed to Africa's weak adaptive
capacity, increasing the continent's vulnerability to projected
climate change.
* African farmers have developed several adaptation options to cope
with current climate variability, but such adaptations may not be
sufficient for future changes of climate (high confidence).
Human or societal adaptive capacity, identified as being low for
Africa in the Third Assessment Report, is now better understood and
this understanding is supported by several case studies of both
current and future adaptation options. However, such advances in
the science of adaptation to climate change and variability,
including both contextual and outcome vulnerabilities to climate
variability and climate change, show that these adaptations may be
insufficient to cope with future changes of climate.
* Agricultural production and food security (including access to
food) in many African countries and regions are likely to be
severely compromised by climate change and climate variability
(high confidence).
A number of countries in Africa already face semi-arid conditions
that make agriculture challenging, and climate change will be
likely to reduce the length of growing season as well as force
large regions of marginal agriculture out of production. Projected
reductions in yield in some countries could be as much as 50% by
2020, and crop net revenues could fall by as much as 90% by 2100,
with small-scale farmers being the most affected. This would
adversely affect food security in the continent.
* Climate change will aggravate the water stress currently faced by
some countries, while some countries that currently do not
experience water stress will become at risk of water stress (very
high confidence).
Climate change and variability are likely to impose additional
pressures on water availability, water accessibility and water
demand in Africa. Even without climate change, several countries in
Africa, particularly in northern Africa, will exceed the limits of
their economically usable land-based water resources before 2025.
About 25% of Africa's population (about 200 million people)
currently experience high water stress. The population at risk of
increased water stress in Africa is projected to be between 75-250
million and 350-600 million people by the 2020s and 2050s,
respectively.
* Changes in a variety of ecosystems are already being detected,
particularly in southern African ecosystems, at a faster rate than
anticipated (very high confidence).
Climate change, interacting with human drivers such as
deforestation and forest fires, are a threat to Africa's forest
ecosystems. Changes in grasslands and marine ecosystems are also
noticeable. It is estimated that, by the 2080s, the proportion of
arid and semi-arid lands in Africa is likely to increase by 5-8%.
Climate change impacts on Africa's ecosystems will probably have a
negative effect on tourism as, according to one study, between 25
and 40% of mammal species in national parks in sub-Saharan Africa
will become endangered.
* Climate variability and change could result in low-lying lands
being inundated, with resultant impacts on coastal settlements
(high confidence).
Climate variability and change, coupled with human-induced changes,
may also affect ecosystems e.g., mangroves and coral reefs, with
additional consequences for fisheries and tourism. The projection
that sea-level rise could increase flooding, particularly on the
coasts of eastern Africa, will have implications for health.
Sea-level rise will probably increase the high socio-economic and
physical vulnerability of coastal cities. The cost of adaptation to
sea-level rise could amount to at least 5-10% of gross domestic
product.
* Human health, already compromised by a range of factors, could be
further negatively impacted by climate change and climate
variability, e.g., malaria in southern Africa and the East African
highlands (high confidence).
It is likely that climate change will alter the ecology of some
disease vectors in Africa, and consequently the spatial and
temporal transmission of such diseases. Most assessments of health
have concentrated on malaria and there are still debates on the
attribution of malaria resurgence in someAfrican areas. The need
exists to examine the vulnerabilities and impacts of future climate
change on other infectious diseases such as dengue fever,
meningitis and cholera, among others.
***************************************************
Introduction .
9.2.1 Current sensitivity to climate and weather
The climate of the continent is controlled by complex maritime and
terrestrial interactions that produce a variety of climates across
a range of regions, e.g., from the humid tropics to the hyper-arid
Sahara (see Christensen et al., 2007). Climate exerts a significant
control on the day-to-day economic development of Africa,
particularly for the agricultural and water-resources sectors, at
regional, local and household scales. Since the TAR, observed
temperatures have indicated a greater warming trend since the
1960s.Although these trends seem to be consistent over the
continent, the changes are not always uniform. For instance,
decadal warming rates of 0.29 C in the African tropical forests
(Malhi and Wright, 2004) and 0.1 to 0.3 C in South Africa (Kruger
and Shongwe, 2004) have been observed. In South Africa and
Ethiopia, minimum temperatures have increased slightly faster than
maximum or mean temperatures (Conway et al., 2004; Kruger and
Shongwe, 2004). Between 1961 and 2000, there was an increase in the
number of warm spells over southern and westernAfrica, and a
decrease in the number of extremely cold days (New et al., 2006).
In eastern Africa, decreasing trends in temperature from weather
stations located close to the coast or to major inland lakes have
been observed (King'uyu et al., 2000).
For precipitation, the situation is more complicated. Rainfall
exhibits notable spatial and temporal variability (e.g., Hulme et
al., 2005). Interannual rainfall variability is large over most of
Africa and, for some regions, multi-decadal variability is also
substantial. In West Africa (4 -20 N; 20 W-40 E), a decline in
annual rainfall has been observed since the end of the 1960s, with
a decrease of 20 to 40% noted between the periods 1931- 1960 and
1968-1990 (Nicholson et al., 2000; Chappell and Agnew, 2004; Dai et
al., 2004). In the tropical rain-forest zone, declines in mean
annual precipitation of around 4% in West Africa, 3% in North Congo
and 2% in South Congo for the period 1960 to 1998 have been noted
(e.g., Malhi and Wright, 2004).A10%increase in annual rainfall
along the Guinean coast during the last 30 years has, however, also
been observed (Nicholson et al., 2000). In other regions, such as
southern Africa, no long-term trend has been noted. Increased
interannual variability has, however, been observed in the
post-1970 period, with higher rainfall anomalies and more intense
and widespread droughts reported (e.g., Richard et al., 2001;
Fauchereau et al., 2003). In different parts of southern Africa
(e.g., Angola, Namibia,Mozambique,Malawi, Zambia), a significant
increase in heavy rainfall events has also been observed (Usman and
Reason, 2004), including evidence for changes in seasonality and
weather extremes (Tadross et al., 2005a; New et al., 2006). During
recent decades, eastern Africa has been experiencing an
intensifying dipole rainfall pattern on the decadal time-scale. The
dipole is characterised by increasing rainfall over the northern
sector and declining amounts over the southern sector (Schreck and
Semazzi, 2004).
Advances in our understanding of the complex mechanisms responsible
for rainfall variability have been made (see Reason et al.,
2005;Warren et al., 2006;Washington and Preston, 2006; Christensen
et al., 2007). Understanding how possible climateregime changes
(e.g., in El Nino-Southern Oscillation (ENSO) events) may influence
future climate variability is critical in Africa and requires
further research. The drying of the Sahel region since the 1970s
has, for example, been linked to a positive trend in equatorial
Indian Ocean sea-surface temperature (SST), while ENSO is a
significant influence on rainfall at interannual scales (Giannini
et al., 2003; Christensen et al., 2007). In the same region, the
intensity and localisation of the African Easterly Jet (AEJ) and
the Tropical Easterly Jet (TEJ) also influence rainfall variability
(Nicholson and Grist, 2003), as well as SSTs in the Gulf of Guinea
(Vizy and Cook, 2001), and a relationship has also been identified
between the warm Mediterranean Sea and abundant rainfall (Rowell,
2003). The influence of ENSO decadal variations has also been
recognised in south-west Africa, influenced in part by the North
Atlantic Oscillation (NAO) (Nicholson and Selato, 2000). Changes in
the ways these mechanisms influence regional weather patterns have
been identified in southern Africa, where severe droughts have been
linked to regional atmospheric-oceanic anomalies before the 1970s
but to ENSO in more recent decades (Fauchereau et al., 2003).
Several studies also have highlighted the importance of terrestrial
vegetation cover and the associated dynamic feedbacks on the
physical climate (see Christensen et al., 2007). An increase in
vegetation density, for example, has been suggested to result in a
year-round cooling of 0.8 C in the tropics, including tropical
areas ofAfrica (Bounoua et al., 2000). Complex feedback mechanisms,
mainly due to deforestation/land-cover change and changes in
atmospheric dust loadings, also play a role in climate variability,
particularly for drought persistence in the Sahel and its
surrounding areas (Wang and Eltahir, 2000, 2002; Nicholson, 2001;
Semazzi and Song, 2001; Prospero and Lamb, 2003; Zeng, 2003). The
complexity of the interactions precludes 'simple interpretations';
for instance, the role of human-induced factors (e.g., migration),
together with climate, can contribute to changes in vegetation in
the Sahel that feed back into the overall physical system in
complex ways (see, e.g., Eklundh and Olsson, 2003; Held et al.,
2005; Herrmann et al., 2005; Olsson et al., 2005). Mineral dust is
the largest cause of uncertainty in the radiative forcing of the
planet and the key role of the Sahara has long been known. Better
quantitative estimates of Saharan dust loadings and controls on
emissions have now emerged from both satellite and field campaigns
(e.g.,Washington and Todd, 2005;Washington et al., 2006).
Finally, changes in extreme events, such as droughts and floods,
have major implications for numerous Africans and require further
attention. Droughts, notwithstanding current limitations in
modelling capabilities and understanding of atmospheric system
complexity, have attracted much interest over the past 30 years
(AMCEN/UNEP, 2002), particularly with reference to impacts on both
ecological systems and on society. Droughts have long contributed
to human migration, cultural separation, population dislocation and
the collapse of prehistoric and early historic societies (Pandey et
al., 2003). One-third of the people in Africa live in drought-prone
areas and are vulnerable to the impacts of droughts (World Water
Forum, 2000). In Africa, for example, several million people
regularly suffer impacts from droughts and floods. These impacts
are often further exacerbated by health problems, particularly
diarrhoea, cholera and malaria (Few et al., 2004). During the
mid-1980s the economic losses from droughts totalled several
hundred million U.S. dollars (Tarhule and Lamb, 2003). Droughts
have mainly affected the Sahel, the Horn of Africa and southern
Africa, particularly since the end of the 1960s (see Section 9.6.2;
Richard et al., 2001; L'H te et al., 2002; Brooks, 2004;
Christensen et al., 2007; Trenberth et al., 2007). Floods are also
critical and impact onAfrican development. Recurrent floods in some
countries are linked, in some cases, with ENSO events. When such
events occur, important economic and human losses result (e.g., in
Mozambique see Mirza, 2003; Obasi, 2005). Even countries located
in dry areas (Algeria, Tunisia, Egypt, Somalia) have not been
flood-free (Kabat et al., 2002).
********************************************************
Box 9.1. Environmental changes on Mt. Kilimanjaro
There is evidence that climate is modifying natural mountain
ecosystems via complex interactions and feedbacks including, for
example, solar radiation micro-scale processes on Mt. Kilimanjaro
(M闤g and Hardy, 2004; Lemke et al., 2007). Other drivers of change
are also modifying environments on the mountain, including fire,
vegetation changes and human modifications (Hemp, 2005). During the
20th century, the areal extent of Mt. Kilimanjaro's ice fields
decreased by about 80%(Figure 9.2). It has been suggested that if
current climatological conditions persist, the remaining ice fields
are likely to disappear between 2015 and 2020 (Thompson et al.,
2002).
************************************************************
9.6.2 Indigenous knowledge systems
The term 'indigenous knowledge' is used to describe the knowledge
systems developed by a community as opposed to the scientific
knowledge that is generally referred to as 'modern' knowledge
(Ajibade, 2003). Indigenous knowledge is the basis for local-level
decision-making in many rural communities. It has value not only
for the culture in which it evolves, but also for scientists and
planners striving to improve conditions in rural localities.
Incorporating indigenous knowledge into climatechange policies can
lead to the development of effective adaptation strategies that are
cost-effective, participatory and sustainable (Robinson and
Herbert, 2001).
9.6.2.1 Indigenous knowledge in weather forecasting
Local communities and farmers in Africa have developed intricate
systems of gathering, predicting, interpreting and decision-making
in relation to weather. A study in Nigeria, for example, shows that
farmers are able to use knowledge of weather systems such as
rainfall, thunderstorms, windstorms, harmattan (a dry dusty wind
that blows along the north-west coast of Africa) and sunshine to
prepare for future weather (Ajibade and Shokemi, 2003). Indigenous
methods of weather forecasting are known to complement farmers'
planning activities in Nigeria. A similar study in Burkina Faso
showed that farmers' forecasting knowledge encompasses shared and
selective experiences. Elderly male farmers formulate hypotheses
about seasonal rainfall by observing natural phenomena, while
cultural and ritual specialists draw predictions from divination,
visions or dreams (Roncoli et al., 2001). The most widely relied-
upon indicators are the timing, intensity and duration of cold
temperatures during the early part of the dry season (November to
January). Other forecasting indicators include the timing of
fruiting by certain local trees, the water level in streams and
ponds, the nesting behaviour of small quaillike birds, and insect
behaviour in rubbish heaps outside compound walls (Roncoli et al.,
2001).
9.6.2.2 Indigenous knowledge in mitigation and adaptation
African communities and farmers have always coped with changing
environments. They have the knowledge and practices to cope with
adverse environments and shocks. The enhancement of indigenous
capacity is a key to the empowerment of local communities and their
effective participation in the development process (Leautier,
2004). People are better able to adopt new ideas when these can be
seen in the context of existing practices. A study in Zimbabwe
observed that farmers' willingness to use seasonal climate
forecasts increased when the forecasts were presented in
conjunction with and compared with the local indigenous climate
forecasts (Patt and Gwata, 2002).
Local farmers in several parts of Africa have been known to
conserve carbon in soils through the use of zero-tilling practices
in cultivation, mulching, and other soil-management techniques (Dea
and Scoones, 2003). Natural mulches moderate soil temperatures and
extremes, suppress diseases and harmful pests, and conserve soil
moisture. The widespread use of indigenous plant materials, such as
agrochemicals to combat pests that normally attack food crops, has
also been reported among small-scale farmers (Gana, 2003). It is
likely that climate change will alter the ecology of disease
vectors, and such indigenous practices of pest management would be
useful adaptation strategies. Other indigenous strategies that are
adopted by local farmers include: controlled bush clearing; using
tall grasses such as Andropogon gayanus for fixing soil surface
nutrients washed away by runoff; erosion-control bunding to reduce
significantly the effects of runoff; restoring lands by using green
manure; constructing stone dykes; managing low-lying lands and
protecting river banks (AGRHYMET, 2004).
Adaptation strategies that are applied by pastoralists in times of
drought include the use of emergency fodder, culling of weak
livestock for food, and multi-species composition of herds to
survive climate extremes. During drought periods, pastoralists and
agro-pastoralists change from cattle to sheep and goat husbandry,
as the feed requirements of the latter are lower (Seo and
Mendelsohn, 2006b). The pastoralists' nomadic mobility reduces the
pressure on low-capacity grazing areas through their cyclic
movements from the dry northern areas to the wetter southern areas
of the Sahel.
African women are particularly known to possess indigenous
knowledge which helps to maintain household food security,
particularly in times of drought and famine. They often rely on
indigenous plants that are more tolerant to droughts and pests,
providing a reserve for extended periods of economic hardship
(Ramphele, 2004; Eriksen, 2005). In southern Sudan, for example,
women are directly responsible for the selection of all sorghum
seeds saved for planting each year. They preserve a spread of
varieties of seeds that will ensure resistance to the range of
conditions that may arise in any given growing season (Easton and
Roland, 2000).
*************************************************************
AfricaFocus Bulletin is an independent electronic publication
providing reposted commentary and analysis on African issues, with
a particular focus on U.S. and international policies. AfricaFocus
Bulletin is edited by William Minter.
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