Diet, health and climate change

Carbon cycle

To most people, climate change generally means greenhouse gases (carbon dioxide and methane) emitted from burning of fossil fuels (for power generation, transport and industry) leading to increased concentration of greenhouse gases, which contributes to global warming and climate change. So, one may ask, how our diet, health and climate change are related to one another. A special report of the IPCC (Intergovernmental Panel on Climate change) highlighted the contribution of diet to health and climate change. Improved diet can contribute to improved health and address climate change.

According to the IPCC, land use sectors (agriculture and forests) contributed to 23% of global greenhouse gas (GHG) emissions, more than the transport or industry sectors. Food loss and waste alone contributed to around 10% of GHG emissions. Diets dominated by animal fats and processed foods contribute to GHG emissions. It is well known that commercial or industrial scale meat production, storage and transportation consumes very high quantities of energy, water and chemicals. Thus, meat consumption in richer countries and in the urban areas of India is one of the main concerns.

Further, wastage of food, estimated to be 25-40%, also indirectly leads to GHG emissions, since that much of food production and processing could have been avoided in the first place. Thus, the obvious measures to address climate change include shifting to plant-based diets (preferably with minimal or no processing), sourced locally as much as possible, and minimising food waste.

Diets dominated by meat and processed foods, the mainstay of the rich countries, is leading to obesity and heart diseases. This trend is also observed in the urban areas of developing countries such as India, where obesity, heart diseases, etc., are common. Meat and processed food consumption are associated with high consumption of energy and GHG emissions in the production and processing of food. Thus, reducing meat and processed food consumption is associated with reducing obesity, improved heart health and reduced GHG emissions -- truly a win-win.

The implications of climate change on health, though not generally acknowledged by citizens and even mass media, are already significant. According to all the scientific evidence available, climate change impacts on health will be more severe in the coming decades. There are innumerable ways in which climate change directly or indirectly contributes to adverse health implications.

Firstly, heat strokes, already a major killer in India during the summer months, could increase, since all climate change models project a warming of 2 to 4 0C in the coming decades. According to a study published in the Journal of Thermal Biology, in India, 3,014 men died from heat-related causes in 2001-05, which increased to 5,157 in the period 2011-15. Deaths due to heat stroke are under-reported, especially in rural areas. In the coming decades, heat stroke events are projected to increase in frequency and intensity. This is especially true for a large majority of the poor who have to work in fields and under the skies in the mining, construction, roadworks and transportation industries.

Secondly, warming and increased humidity due to climate change will lead to an increased occurrence of vector-borne diseases such as malaria, chikungunya, and dengue.

Thirdly, climate change is projected to increase high intensity rainfall and flooding events. Floods are associated with poor quality drinking water availability and sanitation, leading to cholera, diarrhoea, etc. Further, increased frequency and intensity of extreme events such as hurricanes and cyclones are associated with water-borne diseases.

Fourthly, forest fires are becoming more frequent and more severe in most parts of the world. Forest fires lead to destruction of settlements, loss of crops and even death.

Finally, new evidence published in the Journal of Plant Science, suggests that elevated CO2 concentrations and climate change could impact the nutritional quality of crops such as wheat, peas, rice, maize and sorghum by decreasing protein, zinc and iron value of grains.

There is emerging evidence that excessive winter frost in some regions and absence of winter chill in some other regions could impact the suitability of many vegetables and perennial fruit crops. For example, in many parts of Himachal Pradesh, apple cultivation is already not feasible due to climate change. In addition to these concerns is the overall impact of climate change on food production -- a decline is projected in yields for most crops in countries such as India. Declining food production will affect food security, with reduced access to food leading to hunger and malnutrition.

There is need for a deeper understanding of the relationships between climate change, diet and health. In India, there is limited research on these aspects. There are calls for setting up a Climate Change and Health Research Institute in the US. Given the size of the population and potential large-scale impacts of climate change and large vulnerable populations, India should consider setting up a dedicated research institute, or at least a dedicated programme to start with, to address all aspects of climate change and health.

The experience of lack of preparation for pandemics such as Covid-19, leading to the death of millions, should be learned from. As they say, there is no vaccine for climate change; local, national and global scale efforts are needed to address it. We need a transformational change in the way energy is produced and used, food is produced, processed and consumed, houses are built and serviced, and so on.

According to all assessments, the voluntary commitments made by the countries to the United Nations under the Nationally Determined Contributions to reduce GHG emissions in the Paris Agreement are not enough to keep the rise in global mean temperatures to 1.5-2 0C. So, to sustain food production and security, to ensure healthy diets and health for all, adaptation measures have to be designed and implemented on a massive scale across India in all areas such as food production, water management and health.

(The writer was formerly a professor at Indian Institute of Science, Bengaluru)