Climate Change and Disease. Hans Schweisfurth

global average surface temperature has increased in the last 100 years by 0.74 °C (1). By the end of the 21. century the projected increase for the European region is between 2.3 °C and 6 °C depending on the assumed scenario.

      Anthropogenic emissions of greenhouse gases, in particular from the combustion of fossil fuels, will lead to a warming of the Earth's atmosphere. The greenhouse gas emissions have risen in the last four decades by 70 %. Even if the emissions were abruptly stopped, a temperature increase of more than 0.6 °C until the end of this century would be expected. In the European region, the transport sector is responsible for most emissions. The health consequences can already be observed (tab. 1).

      Natural disasters such as floods, heat waves and droughts are responsible for severe human suffering, a high number of deaths and considerable financial losses. Since 1990, the International database for disaster events in European region has registered a total of more than 1 200 natural events of which about 48 million people were affected and 112 000 people lost their lives. The resulting damage is estimated over 241 billion US $. Extreme temperatures are responsible for the highest number of deaths.

      The increase in extreme weather events can be a threat for thousands of people. During the heat wave in the summer of 2003, a total of 70 000 premature deaths were registered in 12 European countries. It is feared that the summer temperatures as they occurred in 2003, will be the norm by the middle of this century.

      The intensity of heavy precipitation events has increased over the past 50 years. Nearly 20 % of the population of Europe lives in river basins, in which a higher risk of flooding is expected and up to 1.6 million people will be more threatened by floods in coastal areas.

      Climate change has implications for most basic conditions for health: food, water, and air. The agricultural production is vulnerable to the impacts of climate change to an extreme extent. In the Mediterranean region, in South-Eastern Europe and Central Asia lower agricultural yields are expected. It could be possible that by the middle of the 21st century, crop yields in Central Asia could decrease by 30 %. This would lead to a further spread of malnutrition, especially among the poorer rural population, whose family income is heavily dependent on food production.

      Climate change has also impact on food safety. Higher temperatures favor the growth of bacteria in food. Infections with salmonella rise from an ambient temperature of 5 °C for each centigrade of 5 % to 10 %.

      The conflict on water resources in Central and Southern Europe and Central Asia will get worse, so that in 2070 in addition 16 to 44 million people will be affected. An increase in water runoff in higher latitudes by 40 % and a decrease of the flow in the dry areas of medium latitudes by 30 % is projected by mid-century. In Central Asia, 70 % of the total population, but only 25 % of the rural population have access to a safe drinking water supply. These disparities are a cause for the diarrhea-related annual deaths of 13 500 children.

      In 2005 the 40 states of Europe recorded 500 000 premature deaths as a result of pollution by particulate matters (PM). Changing wind conditions, a greater desertification and more frequent bush fires promote the transport of air pollutants over long distances. The expected increase of heat waves in Europe should also lead to an accumulation of episodes with ozone loads. During the heat waves mortality increases because of higher particulate matter and ozone concentration.

      Changes in the distribution and behavior of certain insects and birds are early signs that the biological systems already react to climate change. Many plants and animals have spread to hundreds of kilometers to the North and hundreds of meters in higher altitudes. In Sweden ticks gradually moved to more northerly latitudes and in the Czech Republic to higher altitudes, which results in changes of the method of transmission of infectious diseases by vectors. The mobility of people and goods plays an important role which could be observed by the spread of the Chikungunya virus in 2007 in Italy. Climate change could also diminish the important progress in eliminating malaria some countries in the European region have made.

      The health security of the population may be at risk. Climate change can become noticeable far away from the places where it originates, and trigger competition and conflicts over resources. It is feared that in the Mediterranean region the decreasing availability of water will cause a growing competition between the water needs of the people and the agriculture by the year 2025. Cuts in energy supplies have recently shown us the danger of a dependency and raises concerns in relation to human health and safety. In the EU more than 54 % of the energy consumed is produced by imported sources.

      Climate change will negatively affect economic growth. Already today, more than 60 million people in the eastern part of the European region live in poverty. Climate change can lead to significant inequalities in health care within and between countries and put additional strain on the poorer population groups (fig. 1). Overall, the cost of climate change is estimated up to 5 % of the gross domestic product until the end of the century. Therefore, climate change threatens to undermine the progress in achieving the Millennium development goals.

      Figure 1: Estimated impact of climate change on health in 2000 (4). (DALY: disability adjusted life year).

       Direct health effects by:

      Increased heat waves

      -Drought

      -Forest fires

      Extreme weather events

      -Frequent severe weather

      -Storms, floods

      -Sand storms

      Increased UV radiation

       Indirect health effects by:

      Change of allergen exposure

      -Extended pollen season

      -Changing range of allergen

      Increase of air pollutants

      -Ozone

      -Particulate matters (PM2, 5 - 10, PM10)

      Increased infection risk by spread of vectors and reservoir organism

      Problems of drinking water and food hygiene

      Sea-level elevation

      Migrations

Table 1: Direct and indirect health effects of climate change in Europe (2, 3).

       References

      1 WHO Europe, Faktenblatt Kopenhagen/​Parma, 12. März 2010.

      2 Eis D, Helm D, Laußmann D, Stark K. Klimawandel und Gesundheit – Ein Sachstandsbericht. Hrsg.: Robert-Koch-Institut, Berlin 2010.

      3 Intergovernmental Panel on Climate Change (IPCC). Fourth Assessment Report: Climate Change 2007 (AR4). http://www.ipcc.ch/​publications_and_data/​publications_and_data_reports.shtml#.UT8N_JAwfIU.

      4 Campbell-Lendrum DH, Corvalán CF, Prüss Ustün A. How much disease could climate change cause. In: McMichael AJ et al. Climate Change and human health: risks and responses. Genf WHO 2003.