Climate Change Brings Natural Disasters And Disease


We must prepare for climate change bringing more natural disasters that favour mosquito-borne disease, says Jai P. Narain from the WHO.

Climate change has set in, with global temperatures projected to rise up to 4 degrees Celsius by 2100. Tropical cyclones will likely become more frequent and more intense, rainfall will increase and sea level may rise by up to nearly a metre as tropical sea surface temperatures increase.

Climate change is also expected to bring more natural disasters such as drought and flooding. Such changes will inevitably affect health, particularly in the developing world, leading to more deaths from heat stress, diarrhoeal diseases and malnutrition.

The incidence of mosquito-borne diseases, in particular, is likely to change. 

In some tropical regions bothcyclones and floods create breeding grounds for the mosquitoes that carry malaria and dengue. Poor populations in coastal areas are particularly vulnerable to sea level rise and the associated threat of mosquito-borne disease.

Rising disease

In South and South-East Asia, the last decade has brought many disasters, including devastating floods in the Indian states of Gujarat and Mumbai, super cyclones in India, Bangladesh and Myanmarand tsunamis affecting India, Indonesia, Sri Lanka and Thailand. How natural disasters affect mosquito-borne disease varies from region to region, depending on both the environment and how people live.

With the exception of the super cyclones, all these events exacerbated mosquito-borne diseases, particularly malaria. In India, the floods disrupted health service delivery and led to profuse breeding of mosquitoes, resulting in malaria outbreaks. Drought has also been found responsible for malaria outbreaks in Sri Lanka.

The December 2004 tsunami in the region similarly created wide breeding grounds for mosquitoes, disrupted health services and left over 1.6 millionpeople without shelter. The result was a many-fold rise in malaria in the Andaman Islands from January to April 2005.

And Chikungunya, a disease that had all but been forgotten in India, has reappeared in southern parts of the country and by May 2007 had spread to almost all districts in Kerala. Though the igniting factors could not be pinpointed, the underlying reason is the climate changes that helped Aedes mosquitoes breed and survive.