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Climate change and health
by World Health Organization (WHO)
5:57pm 25th Aug, 2014
 
27 August 2014
  
World Health Organization urges action on climate change to protect global health, by Megan Darby.
  
Leading health experts are urging stronger action on climate change, as the first ever global conference to link the two fields kicks off in Geneva.
  
Bringing together meteorologists, diplomats and medics the gathering highlighted the health threats from climate change.
  
The World Health Organization (WHO), hosting the three-day conference, said green energy and transport policies could save millions of lives each year, by cutting air pollution.
  
It also called for initiatives to help communities prepare for heat, extreme weather, infectious diseases and food insecurity caused by climate change.
  
“The evidence is overwhelming: climate change endangers human health,” said Dr Margaret Chan, WHO director general.
  
“Solutions exist and we need to act decisively to change this trajectory.”
  
The rallying cry builds momentum for action ahead of a climate summit to be hosted by UN secretary general Ban Ki-moon next month.
  
At that summit, world leaders will be invited to make commitments to climate action. The idea is to engage heads of state with the issue before a global treaty is signed in Paris, December 2015.
  
Christiana Figueres, the UN’s climate chief, encouraged delegates to push for a strong agreement.
  
This will “chart a course towards a world with clean air and water, abundant natural resources and happy, health populations,” she said.
  
“Seen in this light, the climate agreement is actually a public health agreement.”
  
Figueres suggested Chan treat climate change as a public health emergency.
  
The conference heard from Michel Jarraud, head of the World Meteorological Organization.
  
The UK’s Prince Charles stated via video conference that, ‘Climate change is the greatest threat to public health of the 21st century’.
  
Climate change is already responsible for tens of thousands of extra deaths each year, according to WHO data.
  
As temperatures rise, mosquitoes carrying malaria and other diseases are spreading into new areas.
  
Shifting weather patterns are hitting crop yields in some regions, triggering malnutrition.
  
And extreme events such as heat waves and floods cause health problems both directly and indirectly, by degrading water supplies.
  
Children and the poor are bearing the greatest burden of climate-related diseases, warned Dr Flavia Bustreo, WHO assistant director general of family, women’s and children’s health.
  
“Without effective action to mitigate and adapt to the adverse effects of climate change on health, society will face one of its most serious health challenges,” said Bustreo.
  
Emissions from burning fossil fuels for transport and energy not only cause climate change, but are a major cause of respiratory and cardiovascular disease.
  
US president Barack Obama highlighted the health benefits of his drive to curb coal emissions.
  
Similarly, smog problems in Chinese cities have prompted the authorities to endeavor to limit the rise of coal power.
  
In 2012, the WHO estimates air pollution killed 7 million people, or one in eight deaths worldwide.
  
Dr Maria Neira, WHO director of public health, said: “There is now solid evidence that mitigating climate change can greatly reduce this toll.”
  
http://www.who.int/globalchange/mediacentre/events/climate-health-conference/en/ http://unfccc.int/files/press/statements/application/pdf/20142708_who_health_climate.pdf
  
August 2014 (WHO fact sheet)
  
Climate change affects the social and environmental determinants of health – clean air, safe drinking water, sufficient food and secure shelter.
  
Between 2030 and 2050, climate change is expected to cause at least 250,000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress.
  
The direct damage costs to health (i.e. excluding costs in health-determining sectors such as agriculture and water and sanitation), is estimated to be between US$ 2-4 billion/year by 2030.
  
Areas with weak health infrastructure – mostly in developing countries – will be the least able to cope without assistance to prepare and respond.
  
Reducing emissions of greenhouse gases through better transport, food and energy-use choices can result in improved health, particularly through reduced air pollution.
  
Climate change
  
Over the last 50 years, human activities – particularly the burning of fossil fuels – have released sufficient quantities of carbon dioxide and other greenhouse gases to trap additional heat in the lower atmosphere and affect the global climate.
  
In the last 100 years, the world has warmed by approximately 0.75oC. Each of the last 3 decades has been successively warmer than any preceding decade since 1850.
  
Sea levels are rising, glaciers are melting and precipitation patterns are changing. Extreme weather events are becoming more intense and frequent.
  
What is the impact of climate change on health?
  
Although global warming may bring some localized benefits, such as fewer winter deaths in temperate climates and increased food production in certain areas, the overall health effects of a changing climate are likely to be overwhelmingly negative. Climate change affects social and environmental determinants of health – clean air, safe drinking water, sufficient food and secure shelter.
  
Extreme heat
  
Extreme high air temperatures contribute directly to deaths from cardiovascular and respiratory disease, particularly among elderly people. In the heat wave of summer 2003 in Europe for example, more than 70 000 excess deaths were recorded.
  
High temperatures also raise the levels of ozone and other pollutants in the air that exacerbate cardiovascular and respiratory disease.
  
Pollen and other aeroallergen levels are also higher in extreme heat. These can trigger asthma, which affects around 300 million people. Ongoing temperature increases are expected to increase this burden.
  
Natural disasters and variable rainfall patterns
  
Globally, the number of reported weather-related natural disasters has more than tripled since the 1960s. Every year, these disasters result in over 60,000 deaths, mainly in developing countries.
  
Rising sea levels and increasingly 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. People may be forced to move, which in turn heightens the risk of a range of health effects, from mental disorders to communicable diseases.
  
Increasingly variable rainfall patterns are likely to affect the supply of fresh water. A lack of safe water can compromise hygiene and increase the risk of diarrhoeal disease, which kills some 600,000 children aged under 5, every year. In extreme cases, water scarcity leads to drought and famine. By the 2090s, climate change is likely to widen the area affected by drought, double the frequency of extreme droughts and increase their average duration six-fold.
  
Floods are also increasing in frequency and intensity. Floods contaminate freshwater supplies, heighten the risk of water-borne diseases, and create breeding grounds for disease-carrying insects such as mosquitoes. They also cause drownings and physical injuries, damage homes and disrupt the supply of medical and health services.
  
Rising temperatures and variable precipitation are likely to decrease the production of staple foods in many of the poorest regions – by up to 50% by 2020 in some African countries. This will increase the prevalence of malnutrition and undernutrition, which currently cause 3.1 million deaths every year.
  
Patterns of infection
  
Climatic conditions strongly affect water-borne diseases and diseases transmitted through insects, snails or other cold blooded animals.
  
Changes in climate are likely to lengthen the transmission seasons of important vector-borne diseases and to alter their geographic range. For example, climate change is projected to widen significantly the area of China where the snail-borne disease schistosomiasis occurs.
  
Malaria is strongly influenced by climate. Transmitted by Anopheles mosquitoes, malaria kills some 800,000 people every year – mainly African children under 5 years old. The Aedes mosquito vector of dengue is also highly sensitive to climate conditions. Studies suggest that climate change could expose an additional 2 billion people to dengue transmission by the 2080s.
  
Measuring the health effects
  
Measuring the health effects from climate change can only be very approximate. Nevertheless, a WHO assessment, taking into account only a subset of the possible health impacts, and assuming continued economic growth and health progress, concluded that climate change is expected to cause at least 250,000 additional deaths per year between 2030 and 2050; 38,000 due to heat exposure in elderly people, 48,000 due to diarrhoea, 60,000 due to malaria, and 95,000 due to childhood under-nutrition.
  
Who is at risk?
  
All populations will be affected by climate change, but some are more vulnerable than others. People living in small island developing states and other coastal regions, megacities, and mountainous and polar regions are particularly vulnerable.
  
Children – in particular, children living in poor countries – are among the most vulnerable to the resulting health risks and will be exposed longer to the health consequences. The health effects are also expected to be more severe for elderly people and people with infirmities or pre-existing medical conditions.
  
Areas with weak health infrastructure – mostly in developing countries – will be the least able to cope without assistance to prepare and respond.
  
Many policies and individual choices have the potential to reduce greenhouse gas emissions and produce major health co-benefits. For example, cleaner energy systems, and promoting the safe use of public transportation and active movement – such as cycling or walking as alternatives to using private vehicles – could reduce carbon emissions, and cut the burden of household air pollution, which causes some 4.8 million deaths per year, and ambient air pollution, which causes about 3.7 million deaths every year.

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