'India is at the bullseye of climate change's heat impacting workers — this has economic effects'

Luke A Parsons is a research scientist at Duke University. Speaking at Times Evoke, he discusses heat impacts on labour in terms of well-being — and the economy:

What is the core of your research?

We use observations of heat, humidity and air pollution outdoors to estimate health and well-being impacts and labour and economic results from emissions and climate change. Knowing how hot and humid it is now is very im-portant for workers exposed to the sun. It is also crucial to know how hard people work — the more intensely people labour, they generate more internal body heat, which must be released to avoid health consequences. If it’s too hot and humid though, someone conduct-ing heavy labour can’t cool off easily. That could cause heat stress, heat-stroke or even a loss of life if people can’t slow down the pace of labour.

Is heat changing with global warming?

Most areas in the tropics or within about 30 degrees of the equator are getting hotter and more humid on average. Also, mornings are getting warmer too. On overnight heat, while not being a medical professional, I understand it’s very important for people exposed to heat during the day to allow their body to cool off at night — however, if the nights are hot and humid, this can’t happen, causing a series of cascading health impacts.

How is India positioned in your surveys?

Think about heat hazards or where it is most hot and humid — one of the most intense locations on Earth thus is the Indo-Gangetic Plain. Next, think of numbers — we are talking of over a billion people in the Indian region impacted by heat. Also, consider the very high numbers of people in India who work outdoors, doing manual labour in agri-culture, construction, forestry, fish-eries, mining, brick factories, collecting firewood, etc. This includes everyone working out in the sun, lift-ing loads and lacking heat protection.

So, India has serious overlapping factors — lots of people, many work-ing-age people and many people con-ducting manual labour, producing internal body heat, overlaid with high heat and humidity conditions. This is a perfect storm of health impacts.

Does this indicate other losses too?

Yes. Of all the labour lost to human heat exposure around the world, we found about half is in India — this country is at the bullseye of climate change and heat exposure impacts on outdoor workers. China is also impacted — large populations live in eastern China which is low-lying and near the coast where it is hotter and more humid seasonally. Still, from weather observations and population data, India seems the most impacted in terms of lost labour productivity.

Quantifying this depends on how workers respond to the heat. If we assume they can respond in a way similar to the acclimatised rice harvesters described in a study by Sahu et al, this can mean around $266 billion lost on average per annum. If we use controlled lab studies, where the participants were more sensitive to heat, that goes to about $600 billion per year. I’d say those numbers are underestimates too because they look at heat and humidity in the shade, without direct sun exposure, and there are probably more workers in the less formal economy than we have statistics for.
What links heat and deforestation?

Several factors impact people’s heat exposure. One is global warming — as we emit greenhouse gases into the atmosphere, they trap heat and don’t allow this to escape into space quickly. So, the globe is warming — we’ve warmed over 1° C in the last 100 years. We’re expecting a couple more degrees in the next 50 to 80 years.

Now, on top of that, if people cut down trees, that raises temperatures locally. Trees conduct photosynthesis and evapotranspiration — this cools the surrounding environment. Our research has found that across trop-ical rainforest regions, there is a strong association between defor-estation and temperatures increasing from half a degree to several degrees Celsius locally. We’re talking about a century worth of climate change tak-ing place in deforested spaces — and that is on top of global warming.

What are some important mitigation and adaptation measures now?

In some instances, people are moving work from the hottest hours to cooler ones. The mechanisation of labour is expensive but it is a pos-sibility. Worker protections are crucial — local regulations at worksites should be encouraged, where, knowing how hot or humid it is, you can say, ‘People should not be working during these hours’ or ‘Work-ers should rest at these times to allow themselves to recover’. Also, resting places must be in the shade, with cool, clean drinking water available to stave off dehydration combining with heat exposure. Many people also work by the hour. Those who are desperate enough will push themselves and harm their bodies — we need to devise measures to protect them.

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