Heat waves attributable in part to climate change are forecast to kill hundreds of thousands in this century, however climate change will also have disastrous effects on water supplies, agriculture, and the spread of disease. Rich and poor alike will be affected, but countries that are already struggling to provide food and water for their people will suffer the most.
Water
Disappearing glaciers, increasing droughts and salt-water intrusion
will greatly worsen our world's current fresh water shortage. The
IPCC estimates 3 billion or more additional people will be at risk of
water shortage due to climate change. The Stockholm
Environment Institute estimates that, using only a moderate projection
of climate change, 63 percent of the global population will live in
countries of significant water stress by 2025.
Food
Droughts, water shortages, rising sea levels, floods, heat waves and
temperature shifts will damage food production in many parts of the
world. Mid-continental areas, including vast parts of Asia and
the US "grain belt", are likely to dry. In areas were
dry land agriculture is dependent solely on rain, such as in
sub-Saharan Africa, even a minimal increase in temperature would
dramatically decrease food production.
One extremely
disturbing case of how a small change can produce unexpected results is
the susceptibility of rice to temperature shifts. According to a
study by the International Rice Research Institute, rice yields
decrease by 10 percent for every 1° C (1.8°F) increase in
minimum night time temperature. Rice is the staple food for
more than half of the world's population – meaning this one unexpected
impact of climate change could have profound consequences.
Health
Climate change increases the spread of disease in a number of
ways. Perhaps most significantly by increasing the range of
tropical and sub-tropical infection bearing pests, such as malaria and
dengue carrying mosquitoes. Roughly 300 million more people will
be at risk of malaria with global warming of about 2-3° C
(3.6-5.4°F). Floods will also compromise water quality –
spreading cholera and other diseases.