A less recognised, but inextricably linked challenge is climate change. Stated to be the greatest global health challenge of the 21st century, the role of climate change in undoing several decades of public health gains is worrisome.
Globally, rising temperatures, increased precipitation and rainfall have resulted in greater frequency of climatic events ranging from fires and floods to droughts and heatwaves. In India alone, such events have been encountered at regular frequency in the last two decades. Air quality is a threat, vector-borne diseases are increasing, and depleting water resources are affecting agricultural production.
The resultant direct and indirect impact on health, nutrition and economic development spans all ages and genders. Low and middle-income countries like India with the most vulnerable populations are likely to be worst-affected, given weaker health systems and poorer infrastructure. This translates into further widening of existing health and economic disparities.
Climate change resulting from growing greenhouse gas (GHG) emissions from human (anthropogenic) activities is a prime cause for global warming and at current GHG emission rates, rising temperatures can have potentially harmful effects on ecosystems, biodiversity and human health and livelihoods.
In India, the major sources of anthropogenic carbon dioxide (major component of GHG) emissions come from combustion of fossil fuels, principally coal, oil and natural gas, apart from emissions from transport, industrial activity, deforestation, changes in land use, agriculture (including livestock) and waste management.
Reducing our carbon emissions therefore becomes of prime importance. Other short-lived climate pollutants include black carbon, methane and ground-level ozone which along with other air pollutants and particulate matter from these same sectors combine to aggravate air quality and cause climate change. The health and environmental co-benefits of addressing air pollution and climate change are therefore increasingly evident.
Climate change impacts health. Air pollutants, including particulate matter, sulphur dioxide, nitrogen dioxide, volatile organic compounds (VOCs), carbon monoxide, black carbon, methane and ozone can affect respiratory and cardiovascular health.
The physiological impacts of rising temperatures causing heat stress, heat exhaustion and stroke are particularly harmful, with children, elderly and those with pre-existing illnesses being particularly vulnerable. Exacerbations of heart failure and acute kidney injury from dehydration can also occur during heatwaves.
Heatwaves in Ahmedabad in 2016 accounted for a 43% increase in all-cause mortality. The change in geographical distribution of disease transmitting agents (vectors) owing to climatic conditions affect disease trends for dengue and malaria, with annual waves of dengue-related hospital admissions and deaths increasing the burden on the health sector.
Drought situations affecting crop yield as well as nutritive value and nutritive diversity of food production can have deleterious consequences on the nutritional status of affected populations, compounding effects in already malnourished communities. Increased incidence of post-flood water-borne diseases occur both because of affected water supplies infiltrated with disease agents and poor sanitation and hygiene conditions during these periods.
The mental health impacts of climate change including stress in post-climatic events and increased suicides by farmers in post-drought situations have also been documented in several regions.
The indirect effects of climate change are a consequence of detrimental social and economic impacts through altered labour capacity, loss of livelihoods, impacts on individual, household and national budgets and conflict situations arising from environmental stressors.
These require to be addressed urgently through the focussed lens of mitigation and adaptation activities that are not just health-centric but encourage systemic changes. These must include strategic identification of polluting sectors with appropriate policies for controlling emissions and stringent measures where they are lacking;
facilitating the phased move from coal to clean/ renewable energies across industrial and residential spaces; measures for resource efficiency for water, food, energy in hospitality, healthcare and industrial sectors with “retrofitting” of existing infrastructure and operations to facilitate this. Therefore, while building climate-resilient communities, a significant all-encompassing strategy that addresses health though the sustainable development agenda will go a long way in setting the trajectory for impactful changes to address health impacts of climate change.
Meanwhile, recognising that India tops the table of nations that will face maximum social and economic costs of climate change at $86 for each additional tonne of carbon dioxide emission (the corresponding figures of the US and China are $48 and $28 respectively) should instigate political will for adequate climate financing. The implications of climate change for India cannot be understated and the time to act is now!