India heat wave to worsen, near all-time records

An unusually intense spring heat wave is bringing blistering heat to large portions of Pakistan and India, with the potential for monthly records for April to fall this week in some areas.

Why it matters: Millions in this heavily populated region lack access to air conditioning, and could suffer from heat-related illnesses, which can be deadly. In addition, the heat will make outdoor work untenable for portions of the day, slowing construction projects and impacting the economy.

The big picture: A large-scale weather pattern conducive to extreme heat is affecting the Indian subcontinent, with some of the hottest temperatures forecast for parts of both India and Pakistan.

  • Already this month, high temperatures have hit 122-year-old records, and the Indian Meteorological Department (IMD) is warning of even more stifling heat to close out April and continuing into June.
  • Normally, heat waves in this region peak in May and June before the arrival of monsoon rains, with some of the hottest temperatures anywhere, outside of the Middle East, being recorded. This heat wave is unusually intense for this early in the season, likely enhanced by below average rainfall during March.
  • Research has also directly linked increasingly intense and long-lasting heat waves around the world with human-caused global warming.
  • For example, scientists concluded the heat wave that struck the Pacific Northwest last year would not have occurred without the influence of human emissions of greenhouse gases from the burning of fossil fuels.

Between the lines: India’s daytime high temperatures hit their highest level on record for the month of March, and nationally, the month’s average temperatures ranked as the second-hottest March.

  • During March, northwest and central parts of India including Gujarat, Maharashtra and Delhi experienced early and severe heat waves.
  • During the ongoing heat event, the highest maximum temperature of 45.0°C (113°F) was reported at Wardha, in the state of Maharashtra, on April 25, and Barmer, in West Rajasthan, saw the highest temperature on April 26, with a high of 44.4°C (112°F).

Threat level: According to the IMD, the ongoing heat wave will become even more stifling and dangerous in coming days as an area of ​​high pressure, or heat dome, sits over the country.

  • The IMD is forecasting an increase in daily maximum temperatures by 2 to 4°C during the next three days across Central India, “and no large change thereafter.” Heat wave watches are in effect for this region for the next five days.
  • Computer model projections show temperatures could climb higher by this weekend, potentially up to 49°C (120°F), especially along the border with Pakistan. THE station in Pakistan hit 47°C (116.6°F) on April 26.

Context: India’s average temperature has risen by around 0.7°C, or 1.26°F, between 1901–2018, according to an IMD report, which tied this trend to human emissions of greenhouse gases.

  • That report found that under a worst-case emissions scenario (which is no longer considered the likeliest outcome) extreme heat could increase by 50 to 70% by 2100.
  • However, recent assessments from the UN’s top climate panel projected significant increases in heat waves globally even under more modest warming through 2100.

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