Before the Paris accord on climate protection, health was not a noted concern in the protocols or statements that emerged from the earlier rounds of climate negotiations. This was an astounding omission, considering the huge impact that climate change has on human health, through many pathways.

The global community has now finally recognised that the action on climate change acquires urgency not merely because of unpleasant geophysical phenomena but because of the dangerous physical and mental health effects of unmitigated global warming.

The direct effects of climate change result from the effects of severe heat, floods and extreme weather events. Heatwave-related deaths have become common place in India and even Europe, while floods due to extreme rainfalls have become a worldwide feature.

Recent experiences of Kashmir and Chennai are agonisingly fresh in our minds. Floods kill not only by drowning, but also through the spread of water-borne infections, resulting from contamination of water sources. The rising waters of overheated seas threaten to submerge coastlines and wipe out some island-nations.

The indirect effects of climate change on health are manifest in the form of a spurt in vector-borne diseases, decline of agriculture and nutrition, and impact on mental health and migration. Even as humans lie listless in sweltering heat, rising temperatures will enable mosquitoes to vigorously breed at higher altitudes and latitudes. Malaria, Chikunguniya and Dengue will spread.

It has been estimated that inter-personal conflicts will rise by 2.4 per cent and inter-group conflicts by 11.3 per cent as people get hot tempered in the heat. Extreme heat, drought, water shortages and floods will trigger mass migration and climate refugees will suffer the risk of infections, violence, sexual abuse and mental illness.

Impact on agriculture

Agricultural production and nutrient quality of both staples and non-staples will decline. It is estimated that over the next four decades, global demand for food will rise by 14 per cent per decade (due to population growth, urbanisation and reduced poverty), while production will decline by two per cent per decade (due to effects of climate change on agriculture and livestock). South Asia and Africa are expected to suffer the most, with a projected 10 per cent decline in the production of staples for each degree centigrade rise in temperature and their nutrient levels fall with rising atmospheric carbon dioxide levels and soul erosion.

The heatwave in Russia in 2010 reduced grain production by 40 per cent and resulted in severe food price fluctuations across the world. Other nutrient rich crops too suffer from drought, pests and temperature fluctuations, as dietary diversity and nutrition security become endangered.

Air pollution

A degraded environment also poses an immediate threat, with an estimated 1.7 million Indians dying each year due to indoor and outdoor air pollution. Many of the causes of air pollution are also causes of climate change. Action on these common determinants can prevent a wide array of diseases, even while protecting the climate. Even as urgent action is needed to mitigate global warming, measures are also required for adaptation and climate resilience.

The Ahmedabad Heat Action Plan is a good example of planned urban response to heatwaves.

Climate smart agriculture too becomes an essential adaptive strategy, by growing heat resistant and nutrient rich non-staples. At the same time, agriculture and food systems too must become more sustainable — at present they contribute to 29 per cent of global greenhouse gas emissions, 80 per cent of deforestation and 70 per cent of water use. Health, nutrition and climate are indeed inseparable in the global development agenda.