Heat wave

High pressure in the upper atmosphere traps heat near the ground, forming a heat wave

A heat wave, or heatwave,[1] or extreme heat, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary,[2] a heat wave is usually measured relative to the usual climate in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heat wave in a cooler area if they are outside the normal climate pattern for that area.[3]

The term is applied both to hot weather variations and to extraordinary spells of hot weather which may occur only once a century. Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, increased risk of wildfires in areas with drought, and widespread power outages due to increased use of air conditioning. A heat wave is considered extreme weather, and poses danger to human health because heat and sunlight overwhelm the human body's cooling system. Heat waves can usually be detected using forecasting instruments so that a warning can be issued.

Heatwaves often have complex effects on human economies, due to less productivity of workers, disruption of agricultural and industrial processes and damage to infrastructure not adapted for extreme heat.[4][5]

Heatwaves have become more frequent, and over land more intense, almost everywhere since the 1950s, due to climate change.[6]

  1. ^ "heatwave noun - Definition". gcunoxfohoarnersdictionaries.com.
  2. ^ Meehl, G. A (2004). "More Intense, More Frequent, and Longer Lasting Heat Waves in the 21st Century". Science. 305 (5686): 994–7. Bibcode:2004Sci...305..994M. doi:10.1126/science.1098704. PMID 15310900.
  3. ^ Robinson, Peter J (2001). "On the Definition of a Heat Wave". Journal of Applied Meteorology. 40 (4): 762–775. Bibcode:2001JApMe..40..762R. doi:10.1175/1520-0450(2001)040<0762:OTDOAH>2.0.CO;2.
  4. ^ Bottollier-Depois, Amélie. "Deadly heatwaves threaten economies too". phys.org. Retrieved 15 July 2022.
  5. ^ García-León, David; Casanueva, Ana; Standardi, Gabriele; Burgstall, Annkatrin; Flouris, Andreas D.; Nybo, Lars (4 October 2021). "Current and projected regional economic impacts of heatwaves in Europe". Nature Communications. 12 (1): 5807. Bibcode:2021NatCo..12.5807G. doi:10.1038/s41467-021-26050-z. ISSN 2041-1723. PMC 8490455. PMID 34608159.
  6. ^ "Summary for Policymakers" (PDF). Climate Change 2021: The Physical Science Basis. Intergovernmental Panel on Climate Change. 2021. pp. 8–10. Archived (PDF) from the original on 4 November 2021.