Why climate change impacts human health
It can affect breeding of vectors, reduce availability of food and water, and lead to outbreaks of diseases
The impact of climate change on human health is a clear and present threat. Climate variables affect the quality of air we breathe, the water we drink, the food we eat and even dictate where we can live or work. Increased frequency of severe weather events – searing heatwaves, heavy downpours, floods, droughts – cause death and displacement, damage to public infrastructure as well as reduce the availability of food and drinking water. They also lead to infectious disease outbreaks on one hand and limit access to healthcare on the other. Recognising its need, the Government of India has added ‘human health’ as a mission in the National Action Plan for Climate Change in order to combat the impact on public health.
Mosquitoes are highly sensitive to temperature, humidity and rainfall. Environmental and landscape changes coupled with rise in temperature and humidity levels influence vector behaviour and disease transmission. A case in point is the Indira Gandhi Canal project in Rajasthan, which has altered the ecological profile of the region. As a result, the malaria vector has now overrun the wet and water-logged canal command areas.
Researchers at the Indian Institute of Pub- lic Health, Gandhinagar have created a heat vulnerability map of India, identifying places that are likely to suffer the worst from a spell of high temperature. The index can guide appropriate action plans to protect local communities and has helped reduce deaths due to heat stroke in Ahmedabad this year.
Leveraging space technologies and parameters like sea surface temperature and normalised difference vegetation index will help devise early warning systems for disease outbreaks. El Nino (a warm ocean current phenomenon that results in less rainfall) can cause extreme weather events and impact human health. Malaria epidemics have been associated with excess rainfall in arid areas or where rivers are transformed into pools, conducive for mosquito breeding.
Inclement weather conditions can have an immediate effect on morbidity and mortality. Managing these contingencies can put tremendous stress on the health system. To respond swiftly and effectively, health systems must be equipped to deal with emergencies arising from shifts in weather conditions. Forecast systems will give sufficient lead time to health authorities to strengthen their preparedness mechanisms and gear up well in time to deploy adequate control measures to deal with an impending disease outbreak. Solutions will come from technology and a better understanding of how people and organisations respond to crises. Research, of course, will need to show the way.