Top climate experts told AFP that while the recent disastrous heatwave in India and Pakistan was exceptional, worse, probably far worse, is on the horizon as climate change accelerates.
According to new research published this week, South Asia is statistically ripe for a “big one” even without extra global warming, in the same way that California is thought to be overdue for a huge earthquake.
In March and April, extreme heat scorched most of India and neighbouring Pakistan, exposing over a billion people to temperatures far above 40 degrees Celsius (104 Fahrenheit). The hottest months of the year are still ahead of us.
“This heatwave is likely to kill hundreds,” Robert Rohde, the chief scientist at Berkeley Earth, a climate research organisation, tweeted.
Excess fatalities, particularly among the elderly poor, will only be discovered in retrospect.
According to India’s Ministry of Earth Sciences, heatwave mortality has increased by more than 60 percent since 1980.
However, according to World Meteorological Organization chief Petteri Taalas, “cascading repercussions” on agricultural output, water, energy supply, and other sectors are already visible.
The air quality has deteriorated, and big areas of land are in danger of catching fire.
Last week’s power outages, which occurred as electricity demand reached new highs, served as a warning of what could happen if temperatures continue to rise.
None of this came as a surprise to climate scientists.
“What I find surprising is how astonished most people are, given how long we have been warning about such tragedies,” Camilo Mora, a University of Hawaii lecturer, told AFP.
“This part of the planet, like most other tropical locations, is particularly prone to heat waves.”
The new standard
Mora projected in a landmark 2017 study that by 2100, over half of the world’s population will be exposed to “deadly heat” 20 days or more per year, even if global warming is limited to two degrees Celsius, the Paris Agreement’s cornerstone aim.
To what extent is climate change to blame for the sweltering temperatures in India and Pakistan that have only just begun to subside?
Scientists at Imperial College London’s Grantham Institute are analysing the figures, lead by Friederike Otto, a pioneer in the field of attribution science.
“We’re still figuring out how much more frequent and intense this particular heatwave has become,” she told AFP.
“However, there is no doubt that climate change is a game-changer in terms of excessive heat,” she continued. “In a 2 to 3-degree world, everything we see right now will be commonplace, if not cool.”
On average, the Earth’s surface is 1.1 degrees warmer than pre-industrial levels. Even if all national carbon-cutting goals under the Paris Agreement are met, the planet will still warm by 2.8 degrees.
“More violent heat waves of longer lengths and happening at a higher frequency are expected” in India and Pakistan, according to the Intergovernmental Panel on Climate Change (IPCC).
“We would have witnessed the heat that hit India roughly once every 50 years before human activity enhanced global temperatures,” said Marian Zachariah, a researcher at Imperial College London.
“However, such high temperatures are now only expected every four years.”
In other words, continued global warming will result in more intense heat in the future decades.
Temperature of wet-bulb
According to a new study published in Science Advances, things may get worse even faster.
Since 1960, a team led by Bristol University’s Vikki Thompson has ranked the world’s most severe heatwaves. However, their benchmark was not maximum temperatures, but rather how hot it became in comparison to what was projected for the region.
Surprisingly, South Asia did not even make the top ten.#
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“Heatwaves in India and Pakistan to date have not been all that extreme when defined in terms of deviation from the local average,” Thompson wrote in a commentary.
By that metric, the hottest year in the last six decades occurred in Southeast Asia in 1998.
“Today in India, an equal outlier heatwave would result in temperatures of above 50 degrees throughout broad swaths of the country,” Thompson added.
“India is statistically likely to have a record-breaking heatwave at some point.”
High temperatures paired with humidity, a steam-bath mix with its own yardstick: wet-bulb temperature, are what makes excessive heat lethal (WB).
When the body overheats, the heart beats faster and delivers blood to the skin, which cools it down through sweating. This natural cooling system, however, shuts down above a certain temperature and humidity level.
“Imagine a sunburn on your insides,” Mora explained.
A healthy young adult will die in six hours at a wet-bulb temperature of 35 degrees WB. Nagpur, in central India, briefly registered last week.
“We have seen an increase in heatwaves, floods, cyclones, and droughts in this region as a result of just one degree Celsius,” Roxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology, told AFP.
“It’s tough for me to foresee the consequences of doubling global temperature increases.”
