the bmj | BMJ 2017;359:j5117 | doi: 10.1136/bmj.j5117 1 ANALYSIS Climate change: health effects and response in South Asia Banalata Sen and colleagues call for urgent and inclusive action to address health impacts of climate change in South Asia E xtreme weather events such as cyclones, flooding, and heat spells in South Asia have drawn attention to the effect of climate change on human life and our lack of preparedness. Rapid urbanisa- tion and industrialisation coupled with high population density contribute to emission of greenhouse gases, in par- ticular carbon dioxide (CO 2 ), which lead to a rise in temperature. This has altered precipitation patterns and led to a rise in sea levels. 1 The fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC) notes that key risks for the region are widespread damage to human life, infrastructure, and livelihoods from riverine, coastal, and urban flooding; heat related mortality; and drought related water and food shortage causing malnutrition. 1 The 2015 Lancet Commission on Health and Climate Change concluded that although climate change was the biggest public health threat of the 21st century, tackling it could be the greatest global health opportunity. 2 All South Asian countries have ratified the Paris agreement, committing to monitor and reduce greenhouse gas emissions and develop systems to respond to the effects of climate change. 3 However, climate change is not yet given priority in countries’ health agendas. The effect on the poorest and most vulnerable in society is also often neglected in the climate change discourse. We examine the health effects of climate change in South Asian countries and current strategies to address these, and recommend an inclusive approach to climate change adaptation planning in the region. How health is affected by extreme weather events The complex topography of the region, including high mountains, plains, long coastlines, and low lying islands, increases its vulnerability to extreme weather events (table 1). The recent flash floods in Nepal, Bangladesh, and India, reportedly the worst in 100 years, claimed more than 1400 lives, damaged over 7000 schools, submerged a third of Bangladesh, and led to food insecurity for nearly half a million Nepalese people. 11 A rise in the sea levels and melting glaciers pose greater risk of flooding in the coastal plains. A mean sea level rise of 15-38 cm is projected along India’s coast by 2050. 1 The region of the Bay of Bengal, comprising the coast of Bangladesh and eastern coast of India, has witnessed a 20% increase in cyclonic events because of the rise in sea levels and increasing sea surface temperature. 18 These events cause displacement of populations, loss of livelihood, and mental health problems, with urban slum, rural, vulnerable, and marginalised populations being worst affected. The fifth deadliest heatwave in recorded history affected large parts of India and Pakistan in 2015 and claimed around 3500 lives. 19 Heat stress can cause dehydration, acute heat illnesses such as heat exhaustion, and heat stroke, and exacerbate cardiovascular and respiratory diseases. 20 Extreme heat can worsen the already poor air quality observed across South Asia, and lead to respiratory illnesses. 2 Indirect health effects The change in temperature and associated increase in the severity and frequency of precipitation events has altered the distri- bution of diseases. Areas that were previ- ously non-endemic for certain infections are now at risk. Although the region has made substantial progress in malaria con- trol, another mosquito-borne disease—den- gue—is now a major public health problem. Increased rainfall and flooding are pre- cursors for waterborne diseases such as cholera, typhoid, and diarrhoeal diseases. Lower socioeconomic groups tend to be more vulnerable to these diseases. Unpredictable rainfall patterns and temperature fluctuations have led to crop failures. Loss of cultivable land because of droughts and salt water intrusion from rising sea levels is likely to aggravate food insecurity in a region already grappling with high rates of undernutrition among children. 21 In Nepal and the mountains of India, increased temperature and diminished snowfall followed by rapidly receding glaciers have depleted water reservoirs. 11-13 Added to food insecurity is the threat of nutritional insecurity as rising carbon dioxide emissions tend to make staple food crops less nutritious. 21 Livelihood is also affected in the largely agriculture based economies of the region. 21 Droughts and crop failures have led to large numbers of suicides among farmers in central India. Loss of productivity is a concern during the hottest and wettest months of the year. Simulations from South East Asia predict that in 2050, more than half the afternoon work hours will be lost because of the need for rest breaks. 22 Economic loss from climate change is projected to be largest in the agricultural and energy sectors and in coastal areas. 23 Health system preparedness Vulnerability of healthcare facilities to extreme weather events disrupts the deliv- ery of healthcare services, especially during emergencies. 24 25 With overburdened public health infrastructure most countries in the region are underprepared to manage the health risks of climate change. Emergency preparedness and early warning systems for disease and vector surveillance are in place in most countries. However, climate change has not been adequately addressed in the disaster planning process. The US Department of Health and Human Services (HHS) has developed a sustainable and cli- mate resilient healthcare facilities toolkit. 26 Efforts are underway by groups like the global network HealthCare Without Harm to strengthen resilience of healthcare facili- ties in the region, beginning with Nepal and India. 27 The 2016 Paris agreement calls for countries to implement mitigation and adaptation strategies (box 1), supported by global cooperation to enhance capacity and financing as well as transfer of environmentally sound technologies to developing countries to enable sustainable KEY MESSAGES •    South Asia is vulnerable to extreme weather events and ill health resulting from climate change •    Adaptation strategies with a clear focus on health must be prioritised •    Community participation and decen- tralised initiatives to address the effects of climate change must be fostered