Climate change poses a wide range of threats to health, linked to rising temperatures, changes in weather patterns and risks of disasters.
Human health is very closely linked to many environmental factors that climate change threatens to alter in the years ahead.
According to the World Health Organization, climate change since the 1970s was already causing over 150,000 excess deaths every year by 2000 – because of increases in deaths from diarrhea among other diseases.
A top source of scientific information on these threats is the Intergovernmental Panel on Climate Change (IPCC), which gathers thousands of scientists to review the published evidence.
According to the IPCC’s last major assessment report, published in 2007, the likely health impacts of climate change include:
• heat waves that increase risk of death from heat, especially among the young and old;
• heavy rain or snow which increase risks of death, injury and infectious, respiratory and skin diseases;
• droughts that cause shortages of food and water, increasing hunger and malnutrition, and risks of food-borne and water-borne diseases;
• the possibility of more intense tropical cyclones that increase the risk of physical injury and death, water-borne diseases and stress disorders;
• rising sea levels which increase injuries and deaths by drowning in floods, as well as water-borne disease;
• changes to the distribution of species such as mosquitoes that transmit vector-borne diseases such as malaria;
• increased risk of respiratory disease due to poor air quality.
The IPCC also said there would be fewer deaths from cold as winters get warmer, but that any overall benefits of a warmer world would be outweighed by the negative effects.
It added that the effects are currently small but will increase in all countries and regions.
The World Health Organization and the IPCC both point out that there are many ways for countries, communities and citizens to adapt to some of the changes that threaten health – and that there is still time to act.
Adaptation to health threats can include setting up and improving systems to detect and warn of disease outbreaks and life-threatening events such as floods, droughts and major storms. It includes improved emergency medical services and better access to water and sanitation.
In places where excess heat is a threat, adaptation could include fundamental changes to the way societies live and work – such as alternative working hours and modes of dress to protect against extreme heat.
For adaptation to be effective, countries need to make detailed assessments of the health threats climate change poses and to integrate climate-change planning into relevant public health policies.
Under the project, health ministries and other organizations in Barbados, Bhutan, China, Fiji, Kenya, Jordan, and Uzbekistan, will assess ways to adapt their national health systems to respond to climate-related health risks.
China will focus on strengthening early warning and response systems to extreme heat in urban settings. Barbados and Jordan will focus on diarrhea control through safe reuse of wastewater as a response to water scarcity.
Kenya and Bhutan will address vector borne disease risks in the highlands, and Fiji and Bhutan will highlight actions for community awareness and preparedness for flooding.
Journalists who report on climate change and health should take care to be accurately when reporting on risk (see Communicating Risk).
In addition to the IPCC, other useful sources for journalists are the World Health Organization and its Climate-Health blog.
By combining these international sources with local information from health ministries, medical workers and others journalists can examine both the health threats that climate change poses and the steps that are being taken to address them.
Another interesting angle for journalists is to report on the health benefits that efforts to tackle climate change will bring (in addition to reducing the direct threats from climate change).
For example, efforts to reduce greenhouse gas emissions from cars by promoting walking and cycling would also bring direct health benefits in terms of exercise, reduced air pollution and few road accidents.
Likewise, people can reduce their risk of getting cancer by eating less meat (whose production leads to high greenhouse gas emission).
In 2009, The Lancet published a large study on these co-benefits. It is available on the Wellcome Trust website, along with video and audio material.
Lastly, as everyone is concerned about their health and the health of their loved ones, journalists can use health as an entry point to cover many other aspects of climate change.
CASE STUDY – Climate change and malaria
The relation between climate change and infectious diseases is highly controversial. Many people have claimed, for instance, that because malaria is a tropical disease, climate change will cause a big increase in malaria as the planet warms.
The scientific evidence shows that the story is more complicated. It suggests that while the distribution of malaria could change, this does not mean that all areas will be at greater risk. Indeed some places may become too hot or dry for the malaria parasite or the mosquitoes that transmit it to people when they bite.
In fact, malaria used to occur as far north as Scandinavia and North America and its decline actually occurred as global temperatures were rising. Many other factors were at play – including farming and deforestation, population densities and migration, and the use of drugs and pesticides.
Nonetheless, there is also strong evidence that local climate is a factor that helps to determine how big a threat malaria is. Recent studies have shown that in some places where highland areas have become warmer, the incidence of malaria has increased.
What is missing is data. There is very little good information about historical climate and numbers of malaria cases for large parts of the developing countries that the disease currently affects. Present day information from the least developed areas is also very poor.
This makes it extremely difficult for scientists to predict what climate change will really mean for a disease such as malaria. As with other vector-borne diseases, this makes prevention a priority.
Climate and Health Council
World Health Organization – Protecting Health from Climate Change [pdf]
The Lancet (2009) – Managing the health effects of climate change
The Malaria Myths of Climate Change