Continental Divide: Why Africa’s Climate Change Burden Is Greater Africa can easily be said to contribute the least of any continent
to global warming. Each year Africa produces an average of just
over 1 metric ton of the greenhouse gas carbon dioxide per person,
according to the U.S. Department of Energy’s International
Energy Annual 2002. The most industrialized African countries,
such as South Africa, generate 8.44 metric tons per person, and
the least developed countries, such as Mali, generate less than
a tenth of a metric ton per person. By comparison, each American
generates almost 16 metric tons per year. That adds up to the
United States alone generating 5.7 billion metric tons of carbon
dioxide per year (about 23% of the world total, making it the
leading producer), while Africa as a whole contributes only 918.49
million metric tons (less than 4%). It is a cruel irony that,
in many experts’ opinion, the people living on the continent
that has contributed the least to global warming are in line
to be the hardest hit by the resulting climate changes.
“The critical challenge in terms of climate change in
Africa is the way that multiple stressors--such as the spread
of HIV/AIDS, the effects of economic globalization, the privatization
of resources, and conflict--converge with climate change,” says
Siri Eriksen, a senior research fellow in sociology and human
geography at the University of Oslo. “It is where several
stressors reinforce each other that societies become vulnerable,
and impacts of climate change can be particularly severe.” She
cites the example of the 2002 drought-triggered famine in southern
Africa, which affected millions due partly to populations’ coping
capacity being weakened by HIV/AIDS.
“Climate change could undo even the little progress most
African countries have achieved so far in terms of development,” says
Anthony Nyong, a professor of environmental science at the University
of Jos in Nigeria. With climate change has come an increase in
health problems such as malaria, meningitis, and dengue fever,
he says. This means that the few resources these poor countries
have that would have been channeled into essential projects to
further economic development must instead be put toward health
crisis after health crisis, providing emergency care for
the people.
Models of Change
Africa may already be feeling the effects of global warming,
says Isaac Held, a senior research scientist at the National
Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid
Dynamics Laboratory, and more marked effects are likely to come,
according to models developed by climate scientists around the
world. Projected effects of global warming on precipitation throughout
the world can be summarized in a single sentence, according to
Held: areas that already get a lot of rainfall--such as the equatorial
and subpolar rain belts--will get more, and areas that get little--such
as the subtropical dry zones--will get less.
Climate models suggest that subtropical Africa south of the
equator will follow this trend, and a plausible case can be made
that global warming has already reduced rainfall in that region.
In a paper published in the September 2004 issue of the International
Journal of Climatology, NOAA scientist Pingping Xie and colleagues
wrote, “Large decreasing rainfall trends were widespread
in the Sahel from the late 1950s to the late 1980s; thereafter,
Sahel rainfall has
recovered somewhat through 2003, even though the drought conditions have not
ended in the region.” The study also found that major multiyear oscillations
have appeared to occur more frequently and to be more extreme since the late
1980s.
About 300,000 people died in a prolonged drought in the Sahel
during the 1970s. Until recently the scientific community attributed
that drought to the severe loss of vegetation accompanying such
factors as overgrazing and overpopulation; according to this
model, the reduction in vegetation meant greater reflectivity
of the Earth’s surface and less moisture being returned
to the atmosphere, with a net drying effect. But now, Held says, “we
think of that drought as having been driven by changes in the
ocean temperatures.”
New climate models posit that precipitation changes are occurring
because of alterations in the temperature gradient between the
Southern and Northern hemispheres. “When the [ocean] waters
are warmer in the Northern Hemisphere, rains are attracted farther
north, and when they are warmer in the Southern Hemisphere, it
doesn’t get as far north,” Held explains.
But it is a subject of debate, he says, whether the changes
in temperature gradient that caused the Sahel drought were due
to natural variability of the oceans or were partly the result
of man-made changes in the composition of the atmosphere. There
is as yet no consensus among climate modelers on the most likely
future trend of Sahel rainfall, he emphasizes.
Still, climatologists agree that warming is happening. In Climate
Change 2001: Impacts, Adaptation and Vulnerability, the
Intergovernmental Panel on Climate Change Working Group II
reported, “The historical climate record for Africa shows
warming of approximately 0.7°C [1.3°F] over most of
the continent during the twentieth century; a decrease in rainfall
over large portions of the Sahel . . . and an increase in rainfall
in east central Africa.”
Accompanying the Sahel droughts has been an increase in dust
storms, although whether these storms are a result of the droughts
or a cause has been a subject of controversy. Research published
in the 22 May 2001 issue of the Proceedings of the National
Academy of Sciences, for example, presents an analysis that
demonstrated that the particles in Sahel dust storms weren’t
able to absorb much water. As a result, they did not form cloud
condensation nuclei, as is usually expected in such dust particles,
and so they suppressed rainfall and exacerbated the droughts.
In addition to effects on weather, dust motes averaging less
than 2.5 micrometers in diameter are in the range of particles
that research shows may have serious health consequences. Such
dust can carry with it a variety of hitchhikers including bacteria,
fungi, and chemical pollutants, all of which may adversely affect
health.
Food Stock Failure
On any continent crop failure means trouble, but in Africa
it’s a catastrophe. About 40% of the gross national product
of African countries flows from agriculture, and about 70% of
African workers are employed in agriculture, most of them on
small plots of land. “Africa is full of poor people who
are very highly dependent on climate-related issues for their
livelihoods,” says Bob Scholes, an ecologist at the Council
for Scientific and Industrial Research in Pretoria, South Africa. “They
are subsistence farmers in often very marginal environments.” African
governments are frequently chaotic, ineffective, unstable, and
corrupt, adding to the people’s precarious existence.
Land ownership changes, less restrictive trade policies, commercialization
of the agricultural sector, and increasing impoverishment, along
with population growth, have pushed people into farming in dry
areas, such as savanna, that not long ago were open to cattle
and wildlife grazing, says Jennifer Olson, regional coordinator
for land use with the LUCID (Land Use, Change, Impacts, and Dynamics)
project at the International Livestock Research Institute in
Kenya and a geography professor at Michigan State University.
Faced with shrinking open grasslands, once solely pastoral people
are settling down and planting crops of their own to supplement
their livestock. New farmers tend to be poor, Olson says, and
their farms, set in these dry areas, are usually small and thus
especially vulnerable to droughts, floods, and other weather
hazards associated with climate change.
“Rainfall is the biggest variable for crop and animal
production here,” Olson says. “Everything goes up
and down depending on how the rainy seasons are going, so climate
change is going to have a huge impact with the expansion of the
number of people doing cropping in the more marginal areas. These
tend to be the people on the edge of doing well anyway because
there’s not enough rainfall for them to be productive.”
According to Robert Mendelsohn, a professor at the Yale School
of Forestry and Environmental Studies, small farmers in Africa
are especially vulnerable to changes in precipitation. Only a
small number use irrigation or fertilizer of any kind. Larger
growers, such as the commercial farms of parts of East Africa,
are better able to cope with weather extremes, but they are in
the minority.
People who depend on livestock will be just as hard-hit as
pastures go brown, Mendelsohn says. But in this case smaller
spreads fare better than large ones. Big operations are usually
committed to herds of cattle, which demand plentiful water and
easy-to-reach areas in which to graze. When water is scarce,
large pastoralists are forced to move their herds southward to
relatively wetter areas that are usually occupied by sedentary
farmers, thus precipitating intergroup conflicts. However, people
who have just a few animals can switch to goats and sheep, animals
that tend to be more inventive when it comes to finding food
and water.
Ecosystem Changes
With changes in land use and climate, some areas in East Africa
have become drier, Olson says, and water sources are becoming
intermittent or disappearing. Streams that used to run year-round
are now seasonal. The expansion of agriculture into savannas
also blocks migration routes for large animals such as zebras,
wildebeest, and elephants, she says.
As a result of climate-related ecosystem changes, some wild
sources of food are also becoming harder to find, says Catherine
O’Reilly, an assistant professor of environmental science
at Vassar College. The fish stock in the deep Rift Valley lakes
of East Africa, for example, are decreasing as average air temperatures
rise. These lakes--a chain of fresh and brackish bodies including
lakes Malawi, Tanganyika, and Victoria--contain greater biodiversity
than any other of the world’s freshwater systems, she says.
That diversity depends on algae that are supplied when surface
waters mix with nutrient-rich deep waters.
“With climate change,” O’Reilly explains, “there
is less of this mixing, because the [temperature-mediated] density
difference between the surface waters and the deep waters has
gotten greater, and so it takes more energy to mix deep water
up to the surface.” Less algae means less food for the
entire food web, and the result, she says, is big decreases in
fish catches in all of these lakes.
O’Reilly and colleagues reported in the 14 August 2003
issue of Nature that climate change had contributed
to a 30% decline in Lake Tanganyika fish stocks over the past
80 years. Such declines can be disastrous for the villages in
the region, where the average income is less than US$250 per
year, and where the people depend on the fish from these lakes
for all of their protein.
When this important food source fades, every aspect of the
regional environment is affected. As fish yields go down, increased
demands are put upon the land as some fishermen switch to arable
farming, O’Reilly says. This in turn leads to more intensified
farming, and thus more deforestation, increased erosion, and
degradation of the shoreline. Degradation of the shoreline destroys
in-shore habitat and spawning grounds for many fish species,
further impacting the fish population. “You get a positive
feedback loop started,” she says, “whereby a small
decrease in productivity in the lakes can cycle through all these
factors and impact [yet] another aspect of the fish life-history
cycle.”
When food sources dry up, Africans also turn to wild game.
This can put pressure on already endangered species and potentially
expose diners to the diseases these exotic animals carry. A report
published in the 12 November 2004 issue of Science showed
that declining fish stocks in Ghana--down by at least 50% since
1970--corresponded with a demand for “bushmeat” that
led to a 76% decline in the numbers of 41 species of mammals,
including buffalo, antelope, jackals, monkeys, and elephants.
Insects--and with them the diseases they harbor--have also
been affected by new climatic conditions, says Jonathan Patz,
a physician and associate professor of environmental studies
and population health sciences at the University of Wisconsin-Madison.
As Africa has warmed, he says, vectorborne diseases--those in
which a pathogen is carried from one host to another by pests
such as mosquitoes--have increased their range. Malaria, for
example, has moved into higher African latitudes as highlands
have warmed enough for mosquitoes to breed. (However, other experts,
such as Marlies Craig, a malaria researcher at the South African
Medical Research Council in Durban, believe that factors besides
increasing temperatures, such as increased resistance to drugs,
are the cause of this vector spread.) Further, as malaria makes
its way into higher latitudes, it reaches people who didn’t
develop malaria immunity as children. The result is an increase
in adult mortality.
Although some areas may become more suitable for some diseases,
others may become less so, Patz adds--disease vectors don’t
universally seek warmer temperatures. Rather, each has optimum
conditions in which it thrives. In North America, for example,
Patz says the warmer, wetter temperatures that foster some mosquito
growth tend to worsen conditions for the tick that carries Lyme
disease. Similarly, research by a team from the Institut Français
de Recherche Scientifique pour le Développement en Coopération
in Senegal, published in the March 1996 issue of the American
Journal of Tropical Medicine and Hygiene, indicated that
tickborne borreliosis extended its range out of the Sahel and
into West Africa most likely because of the Sahel drought of
the 1970s.
Wages of War
When the apocalyptic horsemen of famine and pestilence appear,
war can’t be far behind. Decreasing pastoral lands, decreasing
available tillable land, decreasing wild game, and decreasing
available water all add up to more strife, Scholes says. “Subtropical
dry, arid areas are going to be a huge source of conflict over
the next half-century because we still have very, very high population
growth rates in those areas, very low economic growth rates,
and deteriorating environment,” he says.
“Basically,” he adds, “not only are the spillover
effects environmental, in terms of dust storms and soil erosion
and so forth, but there is also massive spillover of people moving
out of [more stressed areas] into better resourced areas.” In
relatively developed countries such as Nigeria and South Africa,
30% or more of the population consists of illegal immigrants.
Farmers, pastoralists, and the new agro-pastoralists are already
competing for water and suitable agricultural and grazing land,
Olson says; regional warming and drying can only be expected
to worsen the situation. On occasion, she says, the conflicts
that result from this competition can turn violent, although
most are settled peacefully.
But according to Eriksen, extended periods of increased violent
raiding in parts of East Africa have led to loss of livestock
and land, and have driven people into a state of destitution
that makes them extremely vulnerable to drought events. “Although
many conflicts are politically instigated and driven by underlying
economic inequities in resource access, rather than climate change
as such, increasing drought stress can exacerbate conflict and
violence,” she says.
Strategies for Coping
As a reaction to so much bad news, in July 2005 the G8 countries--Canada,
France, Germany, Italy, Japan, Russia, the United Kingdom, and
the United States--approved a pledge to forgive about US$40 billion
of debt owed by 18 nations, including 14 African countries. These
forgiven debts represent about one-sixth of the total owed by
African nations to the G8 nations and international lenders.
According to Nyong, relief from these debts will allow these
African governments to spend more on local issues related to
climate change. The G8 leaders also committed to double annual
African aid from US$25 billion to US$50 billion.
But debt relief isn’t an instant cure. “We really
have to spend some time exploring the implications of [debt relief]
for rural economies and urban economies,” says David Campbell,
a geography professor at Michigan State University who has studied
East African communities for more than 25 years. It’s also
important, he says, to determine what investment should be made
with financial aid to maintain the resilience of societies, both
urban and rural, in the face of potential increased climatic
variability.
Industrialized nations bear another responsibility, Nyong says: “Just
as Africa is trying to adapt to these adverse impacts of climate
change, the developed countries, particularly the G8 countries,
should put in place a mechanism to which they are committed to
substantially reducing their greenhouse gas emissions. [With
Nigeria] having signed the Kyoto protocol, we want to see definite
plans articulated to achieving the targets set by the protocol.”
Mendelsohn lays out the bottom line: “As the net income
of this land deteriorates, it’s not going to be able to
sustain the number of bodies that are on it anymore. So the question
is, where will these bodies go?” One long-term answer is
to try to increase industrialization in Africa to give people
other alternatives, to move away from climate-sensitive livelihoods
and industries toward those that are not climate-sensitive--ecotourism
has been suggested as one possible replacement for farm income.
In the meantime, Campbell says, “It’s important
that the G8 outcome be committed over the long term to maintaining
[financial aid] policies.” This financial aid, he says,
will be vital to the lives of Africa’s poor, who represent
an ever increasing segment of African society. And climate change
is likely to accelerate such societal stratification, he says.
People who have at least some wealth will be better able to switch
to different crops, buy a different kind of livestock, or combine
growing and herding. “Herders who had taken on farming
appeared to be less vulnerable to drought than the people who
had maintained themselves in terms of subsisting almost entirely
on herding,” Campbell says. “So that diversification
showed itself to be successful in terms of allowing them to cope
with prolonged drought.” However, those Africans who don’t
have sufficient wealth to buffer the effects of increasing climatic
variability will plunge deeper into poverty.
But as much as financial aid is needed, Nyong says, the reality
is that no amount of money is going to stop climate change from
affecting Africa in profound and unpredictable ways. Africa wasn’t
able to prevent the buildup of greenhouse gases, he says; “What
we are left to do now is to adapt to the buildup.”
Scott Fields |