The climate we live in affects many areas of our lives. The quality of the food we eat, the water we drink and our homes are all dependent on our climate and weather. Some scientists have suggested that a warmer world will be a sicker world. While there is not complete agreement that this will be the case, medical researchers have looked at the likely health consequences in the world.

Our changing climate

Climate researchers predict that the climate will become warmer, with high temperatures in the summer becoming more frequent and very cold winters more rare. Winters will become wetter with heavier rain more common.

Direct effects

With winters becoming milder, there are likely to be fewer cold-related deaths. However, there is a danger that bacteria would no longer die-off seasonally during the prolonged cold spell meaning that diseases may spread more widely.

More heat waves will increase the number of hot-weather related deaths. Exposure to higher levels of UV light could cause an extra 50,000 deaths a year from skin cancer and may cause an increase of up to 20,000 cases of cataracts. Warmer summers may cause up to 100,000 extra cases of food poisoning each year.

Higher average global temperatures mean that diseases, or their carriers, may be able to move to areas that were previously too cold for them to survive. It is possible that a mild strain of malaria will become established in localised parts of colder countries for up to four months of the year.

Researchers have also identified other diseases, such as Lyme disease, cholera, dengue fever and yellow fever, that could spread into previously inhospitable areas and therefore affect a wider population. The weather has been shown to be associated with changes in birth rates, sperm counts, outbreaks in pneumonia, influenza and bronchitis.

Secondary effects

Globally, there are likely to be more floods, more droughts and more storms, which will be accompanied by damage to our homes, food and water supplies and impact on our general health. An increase in flooding will promote the spread of water-borne diseases plus the growth of fungi, while droughts encourage white flies, locusts and rodents, all affecting food and water supplies and health.

Further examples

The World Health Organization and NASA scientists have been studying the relationship between outbreaks of Ebola in Africa and weather patterns. They believe that a rare climate pattern may precede outbreaks of the disease. However, the natural reservoir of Ebola is still unknown - the current favourite culprits are mice or shrews, although there are theories that favour certain plants whose reproductive cycles are directly linked to weather patterns.

Another example was found in edible oysters - warmer winters in the 1990s allowed a parasite previously confined to warmer waters to spread north and infect oysters along the east coast of the US.

The future

Climate change is likely to have an unequal impact on the world population. Those living in poor and developing countries are going to be less able to adapt to changes. The effects on general health are likely to be severe. Health impacts are not likely to be confined to the human population - wildlife will also be severly affected.