On 17 October, I was fortunate to attend a daylong seminar at BMA House on “the health and security perspectives of climate change.” Uniquely, this programme pulled together medical and military professionals along with climatologists, zoologists, and politicians. The morning focused on threats to global climate, health, and security whereas the afternoon sessions focused on the way forward.
The health risks from climate change might seem more obvious than the security risks, but what I learnt is that situations in Darfur and Somalia are the perfect storm examples of the intersection of climate change, health and security. In Bangladesh, if we project forward to a world without improvement and with increased violent weather and rising sea levels, we will encounter a situation in which some 75 million Bangladeshi people (half of the population) are at risk of displacement along with the stability of the nation despite long term excellence in disaster planning and management.
When I worked on an NCD related project with colleagues from the Maldives, the wry comments, which rang true, were always about how the health and health system of the nation would suffer when islands began to disappear into the ocean. To the most pessimistic, climate change can be such an over powering issue in itself that it makes single disease focused programmes or even health systems strengthening seem a bit like re-arranging deck chairs on the Titanic.
Climate change is an emerging threat to global public health. It is now widely accepted that climate change is occurring as a result of emissions of greenhouse gases, especially from fossil fuel combustion. Climate change is predicted to affect many natural systems and habitats, for example, increasing the frequency and intensity of heat waves, increasing the number of floods and droughts, altering the geographic range and seasonality of certain infectious diseases, and disturbing food producing ecosystems, which in turn will affect human health both directly and indirectly. Direct health effects include changes in mortality and morbidity, and changes in respiratory diseases from heat waves. In terms of indirect health effects, these are much more extensive and include changes in the distribution of vector borne diseases, the nutritional and health consequences of regional changes in agricultural productivity, and the various consequences of rising sea levels, flooding, and droughts. [1-3]
Climate change is highly inequitable, and the paradox is that those at greatest risk are the poorest populations in developing countries who have contributed least to greenhouse gas emissions. However, rapid economic development and concurrent pollution means that developing countries are now vulnerable to adverse health effects from climate change and, simultaneously, are becoming an increasing contributor to the problem. [2-4]
Although the effects of climate change affect all levels and ages of any single population, the elderly and those with pre-existing medical conditions are seen as being the most vulnerable. Conversely, major diseases that are most sensitive to climate change such as diarrhoea, malaria, and infections associated with malnutrition are most serious in children living in poverty, making them highly vulnerable to the resulting disease burden. 
Many of the projected impacts on health are avoidable, and public health policy makers need to act to reduce or negate the impact caused by climate change through a combination of short term public health interventions. The most effective responses are likely to be strengthening of the key functions of environmental management, surveillance, and responses to protect health from natural disasters and changes in infectious disease patterns, and strengthening of the existing public health systems.[2,3] However, countries need to assess their main health vulnerabilities and prioritise adoptive action accordingly, keeping in mind the costs involved.
However, the challenges of climate change, health, and security are even greater than imagined and present a different level of problem than is encountered in other issues. Firstly, the problem is truly global. The livelihood of every person in every nation is at risk so that the poor and illiterate and the wealthy and educated will be impacted such that the problem requires an intensity and cooperation among nations rather than competition. Secondly, climate change is cumulative and irreversible, so that policy failure is not an option. We have one chance to get it right because CO2 is long lasting and there must be an indefinite commitment to a course of action around carbon goals because they cannot be reset. Finally, successful approaches to climate change may require a complete transformation of the human condition so that people will use resources differently and with greater cooperation.
If you would like to read and sign the statement calling for urgent action on climate change, you should visit: climatechange.bmj.com/statement. Even if you do not envision yourself signing the statement, you will learn about the benefits to your health and the health of your loved ones from a society more focused on the environment.
1. McMichael AJ, Haines A. Global climate change: the potential effects on health. BMJ 1997;315:805.
2. World Health Organization. Protecting health from climate change: connecting
science, policy and people. Geneva (Switzerland): World Health Organization;
3. Haines A, Kovatsa RS, Campbell-Lendrumb D, et al. Climate change and human
health: impacts, vulnerability and public health. Public Health 2006;120:585–96.
4. Campbell-Lendrum D, Corvalan C. Climate change and developing-country cities:
implications for environmental health and equity. J UrbanHealth 2007;84(1):i109–17.
Tracey Koehlmoos is programme head for health and family planning systems at ICDDR,B and adjunct professor at the James P Grant School of Public Health, BRAC University, Dhaka, Bangladesh.