World Environment Day: 600 million Indians would be exposed to heat wave

Hyderabad: It’s World Environment Day and given the grim outcome of human indifference toward climate change and global warming, there seems nothing to rejoice about.

Rather, a new research that outlines the human cost of climate inaction, points out that around two billion people (22% of the projected end-of-century population) will be exposed to dangerous heat conditions if global warming is not limited from its recent level. India too would witness the greatest population (around 600 million or 60 crores) exposed to extreme heat in the future at this rate of global warming.

Study on global warming

A new study has revealed about 60 million people are already exposed to dangerous heat (average temperature of 29°C or higher).

Titled ‘Quantifying the Human Cost of Global Warming’, the study was published in ‘Nature Sustainability’. The research was led by researchers at the Global Systems Institute, University of Exeter, associated with the Earth Commission, and Nanjing University. They focused on how the current climate policies will leave more than a fifth of humanity exposed to dangerously hot temperatures by 2100.

Current climate policies pose a threat

Despite the Paris Agreement pledge to keep global warming well below 2°C (compared to pre-industrial levels), current policies are projected to result in 2.7°C warming by the end of the century. As per the study, if warming is successfully limited to 1.5°C instead of 2.7, a sixth of humanity would be saved from dangerous heat and only 5 % will be exposed, which is a reminder of the urgent need for decisive action to rapidly reduce carbon emissions. The research team stresses that the worst of these impacts can be avoided by rapid action to cut greenhouse gas emissions.

Need to reduce carbon emissions

The study also finds in “worst-case scenarios” of 3.6°C or even 4.4°C global warming, half of the world’s population could be at an “existential risk.”

Referring to the study, Professor Tim Lenton, director of the Global Systems Institute at the University of Exeter says, “For every 0.1°C of warming above present levels, about 140 million more people will be exposed to dangerous heat. This reveals both the scale of the problem and the importance of decisive action to reduce carbon emissions. Limiting global warming to 1.5°C rather than 2.7°C would mean five times fewer people in 2100 being exposed to dangerous heat.”

Human population density has peaked in places with an average temperature of about 13°C, with a secondary peak at about 27°C (monsoon climates, especially in South Asia). Although less than 1% of humanity currently lives in places of dangerous heat exposure, the study shows climate change has already put more than 60 million people in a risky zone.

Impact of high temperatures

“High temperatures have been linked to issues including increased mortality, decreased labor productivity, decreased cognitive performance, impaired learning, adverse pregnancy outcomes, decreased crop yield, increased conflict, and infectious disease spread,” says Professor Chi Xu, of Nanjing University.

While some cooler places may become more habitable due to climate change, population growth is projected to be highest in places at risk of dangerous heat, especially India and Nigeria.

India will have the highest population exposed to heat

Assuming a future global population of 9.5 billion people, India would have the greatest population exposed to 2.7°C global warming, around 600 million. At 1.5°C, this figure would be far lower, at about 90 million.

Nigeria would have the second-largest heat-exposed population at 2.7°C global warming, more than 300 million. At 1.5°C warming, this would be less than 40 million.

At 2.7°C, almost 100% of some countries including Burkina Faso and Mali will be dangerously hot for humans.

Brazil would have the largest land area exposed to dangerous heat.

Australia and India would also experience massive increases in areas exposed to dangerous heat.