Climate change futures: health, ecological and economic dimensions

estimates (over and above current annual health
expenditure) to reach 40% coverage for prevention
and 50% for treatment (projected 2007 goals) are US
$0.65-1.4 billion for prevention and US $0.6 billion
to US $1.1 billion for treatment. Reaching the 2015
Millennium Development Goals of 70% prevention coverage
and 70% treatment would require increased
annual expenditure of US $1.45-3.2 billion for prevention
and US $1.4-2.5 billion for treatment activities.
WHO’s Roll-Back Malaria and the Global Fund to
Fight AIDS, Tuberculosis and Malaria are among the
new international programs dedicated to addressing
this resurgence.
Widespread drug resistance and lack of resources
and infrastructure for prevention and treatment methods
contribute to the high incidence of malaria in
Mozambique and Zimbabwe and in many other
nations. The cost of medications (US $1-3 per treatment)
and bed nets (US $5) must be viewed in context,
for the total government health expenditures per
capita is US $6 in Mozambique and even less in
many other countries.
THE FUTURE
CCF-I: ESCALATING IMPACTS
Projected changes include the expansion of conditions
that support the transmission of malaria in latitude and
altitude and, in some regions, a longer season during
which malaria may circulate (Tanser et al. 2003; van
Lieshout et al. 2004). Ethiopia, Zimbabwe, and South
Africa are projected to show increases of more than
100% in person-months of exposure later in this century,
changes that could dramatically increase the burden
of those suffering with malaria.
The potential future geographic distributions of malaria
in Zimbabwe were calculated using 16 projections for
climate in 2100 (Ebi et al. in press). The results suggest
that changes in temperature and precipitation
could alter the geographic distribution of malaria in
Zimbabwe; previously unsuitable areas with high population
densities — especially in the now-hospitable
highlands — would become suitable for transmission.
The low-lying savannah and areas with little precipitation
show varying degrees of change. More intense
precipitation events and floods are also projected in
sub-Saharan Africa and these events are expected to
precipitate large outbreaks.
For Brazil, more intense droughts are projected for the
Northeast region due to warming and continued deforestation
in the Amazon. This will increase migration
and the transmission of malaria.
Under CCF-I, therefore, we can anticipate an increase
in the global burden of malaria and mounting adverse
impacts on families, school attendance and performance,
productivity and the ‘climate’ for investment, travel
and tourism. Poor nations with low GNPs will face
the heaviest burdens, devoting more and more of their
precarious resources to combating this disease. The
per capita losses in Disability Adjusted Life Years are
projected to increase substantially. In developed
nations, locally transmitted outbreaks of malaria
increase, necessitating increased use of pesticides,
which carry their own long-term health threats via contamination
of water and food.
CCF-II: SURPRISE IMPACTS
Under CCF-II we project intensification of malaria
transmission throughout highland regions in Africa,
Latin America and Asia, with continued transmission in
lowland regions. In addition, malaria could suddenly
swell in developed nations, especially in those areas
now bordering the margins of current transmission. This
could present severe problems in southern regions of
Western and Eastern Europe and in the southern US.
The impact measured in DALYs would be substantial if
malaria returns to parts of the developed world. The
strains on public health systems and on health insurance
would come at a time when warming and the
intensified hydrological cycle are increasing the overall
burden of disease due to infectious agents. The
increasing use of medicines for treatment and chemicals
for mosquito control would exacerbate drug and
insecticide resistance, boosting the costs of the disease
and the costs of disease control. If the current methods
for combating malaria lose their efficacy as a result of
overuse of these chemical agents, the potential spread
of malaria in a step-wise fashion would pose severe
threats to human health as well as to economic development.
This would be one of the dangerous interactions
envisaged in CCF-II, in which a non-linear
change has an unpredictable cascading effect on society
and social development.
39 | INFECTIOUS AND RESPIRATORY DISEASES
CASE STUDIES