World Meteorological Day

Climate and Health

Early warning systems are critical to protect us from threats to life and health associated with weather events such as storms or heat waves. Some warning systems estimate the wind chill factor or the strength of ultra-violet rays from the sun. Specialized health warnings for allergen levels, air pollution and mosquito activity are of increasing value, and are often accompanied by advice on how to reduce health risks.

For example, the exceptional heat wave experienced in Europe in August 2003 resulted in more than 70 000 excess deaths. As a result, French health and weather authorities collaborated to issue warnings targeting vulnerable groups, such as the elderly and the young.

Collective approach

Public policy related to meteorology and hydrology plays an important role in population health, especially through clean water supply and sanitation services, management of infectious diseases, control of air pollution, support for safe and healthy housing, and well-organized disaster management.

Growing interest and research in health-climate problems have boosted the development of tools and policies for health managers and communities. This team approach combines the expertise of public health specialists with that of economists, ecologists, hydrologists, climate scientists and meteorologists.

Climate change and health

Climate change is likely to affect the health of millions of people in a variety of ways. More intense heat waves pose risks to the health of children and the elderly; the anticipated increase in droughts raises the potential for malnutrition. Drier conditions are more conducive to sand and dust storms that affect the respiratory system.

Many areas are at increasing risk of vector-borne diseases such as malaria, West Nile virus and dengue. Mosquitoes thrive in wetter, warmer conditions, which also make it easier for pathogens such as cholera to survive. Increased rain and flooding can mobilize contaminants.

Conversely, other parts of the world may see reduced exposure to certain disease vectors and there will be fewer deaths from exposure to low temperatures.

The actual outcomes will depend on how societies prepare for the challenges. The use of weather, climate and water information and forecasts will help power this response.

Air pollution

Indoor and outdoor air pollution affects both developed and developing countries and contributes to the global burden of disease from respiratory infections, heart disease, and lung cancer. The World Health Organization estimates that indoor air pollution causes approximately two million premature deaths and may pose a risk to the health of more than half of the world’s population.

The WMO-coordinated Global Atmosphere Watch, which collects information about ozone, ultraviolet and solar radiation and greenhouse gases, also has a special unit to monitor pollution in the urban environment.

A joint report from WMO and the United Nations Environment Programme in 2011 showed there was big potential to cut pollution from black carbon, or soot. This would improve respiratory health. As a big added plus, tackling such pollutants with a short life span in the atmosphere would help reduce global warming.

WMO oversees a Sand and Dust Storm Warning Advisory and Assessment System. This facilitates sand and dust storm forecasting to give advance warning to affected communities, which tend to be in Africa, the Middle East, South-East Asia and the south-western United States. Meteorologists are collaborating with health experts in assessing the role of dust in meningitis epidemics in Africa’s so-called meningitis belt, which spans from Senegal in west Africa to Ethiopia in the east.

Malaria About 3.3 billion people – half of the world’s population – are at risk of malaria. Annually, there are about 250 million cases of the disease and nearly one million deaths. It is especially serious in Africa, where it is linked to one in every five childhood deaths. People living in the poorest countries are the most vulnerable. In some semi-arid areas, the number of malaria cases typically peaks a month or two after the height of the rainy season, when mosquito populations expand. Heavy rain can lead to malaria epidemics. However, in some highland areas, temperature is the most important factor; epidemics occur during unusually warm seasons. Based on these relationships, early warning systems are being developed and tested in several African countries. Theses combine seasonal climate forecasts with monthly data and observations relating to the weather, the mosquito count and the number of malaria cases to make projections. Seasonal forecasts for rainfall and temperature, made three to six months ahead, can provide valuable advance warning for regions at increased epidemic risk.

Shanghai Shanghai in China has a dense population of 18 million people. It is vulnerable to natural hazards such as typhoons, heat and cold waves and is also affected by atmospheric pollution. During the 2010 Shanghai World Expo, the Chinese Meteorological Administration demonstrated new services for air quality, pollen, food poisoning and heat stroke to create an air pollution prediction system for the Shanghai area, and to improve the assessment techniques of environmental quality.

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