Climate Change and Health
Climate change affects the social and environmental determinants of health: clean air, safe drinking water, adequate food and secure housing.
Between 2030 and 2050, climate change is expected to cause nearly 250,000 additional deaths per year due to malnutrition, malaria, diarrhea and heat stress.
The cost of direct damage to health (excluding costs in health-determining sectors such as agriculture and water and sanitation) is estimated to be between US$2 and US$4 billion per year by 2030.
Areas without good health infrastructure, mostly in developing countries, will be the least able to prepare and cope without assistance.
Reducing greenhouse gas emissions by increasing the choice of transport, food, and energy can lead to improved health.
Climate change
Over the past 50 years, human activities, particularly the use of fossil fuels, have released sufficient amounts of carbon dioxide and other greenhouse gases to trap more heat in the lower atmosphere and affect the global climate.
Over the past 130 years, the global temperature has increased by about 0.85°C worldwide. Over the past 25 years, the pace has accelerated to more than 0.18°C warming per decade [1].
Sea levels are rising, glaciers are melting and the distribution of precipitation is changing. Extreme weather events are increasing in intensity and frequency.
What is the impact of climate change on health?
Although global warming may have some local benefits, such as reduced winter mortality in temperate zones or increased food production in some regions, the overall effects are likely to be largely negative. Climate change affects the social determinants of health: clean air, safe drinking water, adequate food and secure housing.
Extreme heat
Hot temperatures contribute directly to mortality from cardiovascular and respiratory diseases, especially among the elderly. During the summer 2003 heat wave in Europe, more than 70,000 additional deaths were recorded [2].
The level of ozone and other pollutants in the air, which exacerbate cardiovascular and respiratory diseases, also increases with temperature.
Concentrations of pollen and other aeroallergens are also higher in extreme heat. They can then trigger asthma attacks, a disease from which about 300 million people suffer. Rising temperatures are expected to increase this burden of disease.
Natural disasters and rainfall variation
Worldwide, the number of weather-related natural disasters has more than tripled since the 1960s. Each year, these disasters have caused more than 60,000 deaths, mainly in developing countries.
Rising sea levels and an increasing number of extreme weather events will destroy homes, medical facilities and other essential services. More than half of the world's population lives within 60 km of the sea. Populations will be forced to move, increasing a range of health risks, from mental health disorders to communicable diseases.
Increasingly erratic rainfall is likely to affect freshwater supplies. Lack of safe water can compromise hygiene and increase the risk of diarrheal diseases, which kill nearly 500,000 children under the age of five per year. In extreme cases, water scarcity leads to drought and famine. It is likely that by 2090, climate change will expand the areas affected by droughts, double the frequency of extreme droughts and increase their average duration sixfold[3].
Floods are also increasing in frequency and intensity. They contaminate freshwater sources, increase the risk of water-borne diseases and create breeding grounds for disease-carrying insects such as mosquitoes. They also cause drowning and physical trauma, damage housing, and disrupt the delivery of health care and health services.
Rising temperatures and erratic rainfall patterns are likely to reduce food production in many of the poorest regions, with up to 50% by 2020 in some African countries [4]. This will result in an increased prevalence of malnutrition and undernutrition, currently causing 3.1 million deaths per year.
Characteristics of infections
Weather conditions strongly influence water-borne diseases and those carried by insects, gastropods or other cold-blooded animals.
Climate change is likely to lengthen the transmission season for some major vector-borne diseases and change their geographical distribution. China, for example, is projected to experience a significant expansion of its endemic area for schistosomiasis, a disease transmitted by gastropods.
Climate also has a strong influence on malaria. Transmitted by Anopheles mosquitoes, it kills nearly 400,000 people a year, most of them African children under the age of 5. Mosquitoes of the genus Aedes, vectors of dengue fever, are also very sensitive to weather conditions. According to some studies, an additional 2 billion people could be at risk of dengue transmission by the 2080s.
Measuring health effects
Measuring the health effects of climate change can only be very approximate. Nevertheless, WHO, in an assessment that considered only a small group of possible health effects, and assumed continued economic growth and health gains, concluded that climate change could lead to about 250,000 additional deaths per year between 2030 and 2050: 38,000 due to heat exposure of the elderly, 48,000 due to diarrhea, 60,000 due to malaria, and 95,000 due to child undernutrition[4].
Who is at risk?
All populations will feel the effects of climate change, but some are more vulnerable than others. Those living in small island developing states or other coastal regions, in megacities, in mountainous regions and in polar areas are particularly vulnerable.
Children, especially those living in poor countries, are among the most vulnerable to the resulting health risks and will be exposed to the consequences for longer. Health effects are also expected to be more severe for the elderly and those with pre-existing disabilities or medical conditions.
Areas without good health infrastructure, mostly in developing countries, will be the least able to prepare and cope without assistance.
0 Commentaires