An average ambient wet-bulb temperature of 35°C, if it persists for long enough, can lead to heat stress, heat stroke and even death. Sleeping outdoors at night or being in the shade cannot cool the body enough.
Air conditioning can help, but low-income families cannot afford it. Surge in energy demand during recent heat waves has already caused frequent power cuts across the region as more energy for air-conditioning overloaded electricity networks.
This year, I lived in New Delhi between March and June. The monthly electricity bill doubled compared to February. Increased use of air conditioning requires additional energy, which in India comes mostly from coal-fired thermal plants and add to greenhouse gas emissions.
Chemical coolants used in older air conditioners models are about 7,000 times more potent greenhouse gases than carbon dioxide. Their increased use adds to further warming.
In contrast to New Delhi, Kathmandu during this time felt naturally air-conditioned. But even Kathmandu Valley with higher humidity than in the past was uncomfortably hot in August and September. There were occasional power-cuts, and it was difficult to sleep without fans.
Rising average global temperatures, heat island effects, and the degradation of natural ecosystems like water bodies and green spaces, combined with the added moisture in the air, will likely lead to increased heat in the Indo-Gangetic plains, Nepal’s Tarai and valley towns.
So, will the rising average summer temperatures and heat in the Ganga plains and across the Indian landmass lead to increased migration to the cooler upland Himalayan areas in future?
Theoretically, people may move to cooler regions like Uttarakhand, Himachal Pradesh, Darjeeling, as well as the mountains of Nepal and Bhutan. Just like when the British ruled India, they moved seasonally to ‘hill stations’ like Darjeeling, Shimla, and Nainital to avoid summers in the plains. When and how could that happen?
Traditional migration patterns, however, have been the opposite, where people from the hills move to the cities in the plains for jobs and better economic opportunities.
But during the summer, the Tarai and valley towns in the hills of Nepal will also get hot and humid. Temperatures are expected to rise in the Himalaya as well.
There are other unknowns: How many people will move? Will it be internally from the Tarai plains, hot river valleys, or will people also cross national boundaries? Answers to these questions can have mind-boggling social and political implications.
In the meantime, it may be worthwhile to reflect on past experience of the potential impact of mass tourism on sensitive Himalayan ecosystems so that we can take ameliorative action.
Increasing heat will impact people’s ability to work, grow food, and seek health care. It will hurt the poor and elderly the most. In Nepal, we have not yet recognised increasing heat as a potential problem– both in terms of threats in the Tarai and river valleys, and the environmental implications of possible move of people up the mountains.
There has been no systematic research of this issue. The least we can do is start to talk about it.
Ajaya Dixit is Executive Director of the Institute for Social and Environmental Transition (ISET) Nepal.