Besides rising temperatures and sea levels, climate change is increasingly leading to extreme rainfall, floods and cyclones to occur at the same time in India, says a new study
“The collision of cumulative climate hazards is not something on the horizon. Co-occurring and colliding climate hazards are already here,” says Camilo Mora, lead author of a new study that provides comprehensive assessment of how humanity is being impacted by the simultaneous occurrence of multiple climate hazards, strengthened by increasing greenhouse gas emissions.
The study published in Nature Climate Change finds evidence for 467 pathways by which human health, water, food, economy, infrastructure and security have been recently impacted by climate hazards such as warming, heatwaves, precipitation, drought, floods, fires, storms, sea-level rise and changes in natural land cover and ocean chemistry.
“We collected climate projections on 11 different climate hazards antagonised by greenhouse gases and found that if the world does not mitigate greenhouse gases (emissions), its human population will have to deal with at least three concurrent hazards with some tropical areas facing simultaneously up to six hazards (through 2100). If we strongly mitigate greenhouse gases, we face on average an equivalent of one hazard,” Mora, Associate Professor in Geography, and conservation researcher in the University of Hawaii at Manoa, told indiaclimatedialogue.net via email.
Interactive maps in the study show by 2100 in India, precipitation and consequent floods, and cyclonic storms are predicted to occur concurrently. It would in addition, with most other countries, face warming, changes in ocean chemistry and sea level rise.
“In this paper, we analysed over 12,000 publications to search for actual case examples of recent climatic changes impacting people. We found over 3,000 documented cases, in which climatic hazards that are being intensified by greenhouse gas emissions have impacted human systems,” Mora told India Climate Dialogue.
Ongoing greenhouse gas emissions are known to increase atmospheric temperature, in turn enhancing soil water evaporation resulting in drought, wildfires and heatwaves in normally dry places or massive rain and floods in commonly wet areas. In the oceans, warmer waters also evaporate faster increasing wind speeds and the downpours of storms, whose surges can be aggravated by sea level rise. As a result, greenhouse gas emissions can simultaneously aggravate multiple climate hazards, the study said.
Co-occurring climate events are already hitting India.
Intensification of climate hazards due to greenhouse gas emissions has been studied separately. However, a focus on one or a few hazards may mask the impacts of other hazards resulting in incomplete assessments of the consequences of climate change on humanity. “The long list of different types of impacts on people from climate change is staggering, and reveals our broad vulnerability to ongoing greenhouse gas emissions,” Mora said.
Impact on health
The study finds 27 aspects of human health impacted by climate hazards of which death, disease and mental health were the most commonly observed. In India, reports of increasingly suicidal ideas is occurring in victims, particularly among farmers, due to not one but several hazards that can happen in a single year – drought, heatwaves, storms and floods.
The study also throws up some less known health impacts of extreme climate events. Children born to pregnant women exposed to floods exhibit increased bedwetting, aggression towards other children, and have below-average birth weight, juvenile height and academic performance.
Climate hazards were increasingly implicated in pre and post-birth and infant health problems. The study cites research saying salinity in drinking water caused by saltwater intrusion and aggravated by sea-level rise is linked to pregnancy co-condition of hypertension, which created serious health issues for both the mother and foetus.
Increasing warming and precipitation changes have created suitable habitat for pathogens and vectors, which are contributing to epidemics of malaria, diarrhoea, dengue fever, salmonella bacterial infection, leptospirosis and cholera which World Health Organisation has warned might rear it head again due to increasing severe heat waves and intense flooding. Cardiac and respiratory disorders are direct heat illness occurring during heatwaves as seen in summer mortalities in India.
“Our health depends on multiple factors, from clean air and water, to safe food and shelter and more,” said co-author Jonathan Patz, professor and director of the University of Wisconsin’s Global Health Institute. “So without an (integrated) systems approach to climate change impacts, we cannot adequately understand the full risks. If we only consider the most direct threats from climate change, for example heatwaves or severe storms, we inevitably will be blindsided by even larger threats that, in combination, can have even broader societal impacts.”
Fundamental change in Indian farming
Impacts of climate hazards on food systems has been the most widely felt in India. “In India, with environmental volatility increasing, yields will be less predictable, which will disproportionately impact small holders,” co-author Michael B. Kantar and assistant professor at the University of Hawaii told iindiaclimatedialogue.net via email.
“Additionally, local conditions are likely to change which may change the crops that can be grown in different regions,” added Kantar, an expert in plant breeding and genetics. The challenge for India’s food system and economy today is how quickly policy and farming community acknowledge climate change and affect a fundamental change that could be a major breakaway from centuries of agricultural practices.
Warming, ocean chemistry and sea level rise are all changing the quantity and quality of fisheries and adding to livelihood and nutritional insecurity for India’s coastal population.
The study findings confirm that the quantity and quality of fresh water were critically impacted by climate hazards. Drought, warming and heatwaves caused wells to run dry and reduced water levels in reservoirs, forcing severe water shortages. Both shortages and floods push people to drink contaminated water which leads to outbreaks of infectious diseases.
Job loss will lead to violence
Infrastructural losses from floods and storms have been visible for long, but heatwaves’ impacts, set to increase in coming decades, are less documented. Heatwaves, for instance, cause overheated power lines to sag into trees and short out. It also reduces the efficiency of power conduction and hydroelectric production from a loss of generator cooling resulting in large blackouts. Disruption from heatwaves have extended to grounding airplanes because hot air is less dense than cold air thus requiring additional speed that airplanes may not be able to achieve on shorter runways.
Climate hazards impact job availability as well as work capacity. Droughts, floods and saline water intrusion have seen cuts in labour engagement in India. Heatwaves too lowered labour productivity; absenteeism increases during heatwaves and in India rules are now in place for longer workdays to compensate for periods of rest during the hottest hours of the day.
Eleven aspects of human security are impacted by climate hazards, critically related to dislocations, increased conflict and violence, and disruption of the social fabric. Climate hazards forced hundreds of millions of people out of their homes for different reasons and durations, including evacuation, displacement and migration.
Impacts of climate hazards on the social fabric were found, including instances of violence, exacerbated gender inequality and breakdown of social order. High temperatures can increase anger, affecting how people respond to provocation, which can aggravate acts of interpersonal violence and violent crimes during heatwaves. Though little of this has been studied in India, in the United States, for instance, warming by 0.5 degree Celsius aggravated rates of rapes by 0.20, robberies by 0.84, burglaries by 8.16, and larcenies by 10.65 per 100,000 people.
The largest losses of human life during extreme climatic events occurs in developing nations, whereas developed nations commonly face a high economic burden. “Thus, while it is commonly noted that developing nations will face most of the burden of current and projected climate change, our integrative analysis of impacts reveals that developed nations will not be spared from adverse impacts,” the study points out.
Michael Mann, Professor of Atmospheric Science at Penn State University, says, “This new research provides rigorous, quantitative support for a point we have emphasised for some time: the costs of inaction greatly outweigh the costs of taking action on climate change.” Mann, who was not involved in this study, adds, “It also provides robust support for another key point: we can still reduce future damage and suffering if we act quickly and dramatically to reduce carbon emissions.”