Editing Extreme weather (section)

===Cold waves===
[[File:Lst neo 20131203-20131210.jpg|thumb|right|250 px|Cold wave in continental North America from Dec. 3–10, 2013. Red color means above mean temperature; blue represents below normal temperature.]]
{{Main|Cold wave}}

<!--Please review MAIN article prior to editing this section - this article is specific to SEVERE WEATHER-->
A cold wave is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the [[National Weather Service|U.S. National Weather Service]], a cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection for agriculture, industry, commerce, and social activities. The precise criterion for a cold wave is determined by the rate at which the temperature falls, and the minimum to which it falls. This minimum temperature is dependent on the geographical region and time of year.<ref>{{cite web|author=Glossary of Meteorology|year=2009|title=Cold Wave|url=http://amsglossary.allenpress.com/glossary/search?id=cold-wave1|archive-url=https://web.archive.org/web/20110514110247/http://amsglossary.allenpress.com/glossary/search?id=cold-wave1|archive-date=2011-05-14|access-date=2009-08-18|publisher=[[American Meteorological Society]]}}</ref> Cold waves generally are capable of occurring at any geological location and are formed by large cool air masses that accumulate over certain regions, caused by movements of air streams.<ref name="EW" />

A cold wave can cause death and injury to livestock and wildlife. Exposure to cold mandates greater [[Food energy|caloric]] intake for all animals, including humans, and if a cold wave is accompanied by heavy and persistent snow, grazing animals may be unable to reach necessary food and water, and die of [[hypothermia]] or starvation. Cold waves often necessitate the purchase of [[fodder]] for livestock at a considerable cost to farmers.<ref name="EW" /> Human populations can be inflicted with [[frostbite]] when exposed for extended periods of time to cold and may result in the loss of limbs or damage to internal organs.

Extreme winter cold often causes poorly [[Thermal insulation|insulated]] water [[pipeline transport|pipes]] to freeze. Even some poorly protected indoor [[plumbing]] may rupture as frozen water expands within them, causing property damage. Fires, paradoxically, become more hazardous during extreme cold. Water mains may break and water supplies may become unreliable, making [[firefighting]] more difficult.<ref name="EW" />

Cold waves that bring unexpected freezes and frosts during the growing season in mid-latitude zones can kill plants during the early and most vulnerable stages of growth. This results in crop failure as plants are killed before they can be [[harvest]]ed economically. Such cold waves have caused [[famine]]s. Cold waves can also cause soil particles to harden and freeze, making it harder for plants and vegetation to grow within these areas. One extreme was the so-called [[Year Without a Summer]] of 1816, one of several years during the 1810s in which numerous crops failed during freakish summer cold snaps after [[volcanic eruption]]s reduced incoming sunlight.

In some cases more frequent extremely cold winter weather – i.e. across parts of Asia and North America  including the [[February 2021 North American cold wave]] – [[Effects of climate change#Effects on weather|can be a result of climate change]] such as due to [[Climate change in the Arctic|changes in the Arctic]].<ref>{{cite news |title=Climate change: Arctic warming linked to colder winters |url=https://www.bbc.com/news/science-environment-58425526 |access-date=20 October 2021 |work=BBC News |date=2 September 2021 |archive-date=20 October 2021 |archive-url=https://web.archive.org/web/20211020112818/https://www.bbc.com/news/science-environment-58425526 |url-status=live }}</ref><ref>{{cite journal |last1=Cohen |first1=Judah |last2=Agel |first2=Laurie |last3=Barlow |first3=Mathew |last4=Garfinkel |first4=Chaim I. |last5=White |first5=Ian |title=Linking Arctic variability and change with extreme winter weather in the United States |journal=Science |date=3 September 2021 |volume=373 |issue=6559 |pages=1116–1121 |doi=10.1126/science.abi9167 |pmid=34516838 |bibcode=2021Sci...373.1116C |s2cid=237402139}}</ref> However, conclusions that link climate change to cold waves are considered to still be controversial.<ref>{{cite web |last1=Irfan |first1=Umair |title=Scientists are divided over whether climate change is fueling extreme cold events |url=https://www.vox.com/22287295/texas-uri-climate-change-cold-polar-vortex-arctic |website=Vox |access-date=24 October 2021 |language=en |date=18 February 2021 |archive-date=23 October 2021 |archive-url=https://web.archive.org/web/20211023071224/https://www.vox.com/22287295/texas-uri-climate-change-cold-polar-vortex-arctic |url-status=live }}</ref>{{Unreliable source?|date=October 2021}}{{additional citation needed|date=October 2021}} The JRC PESETA IV project concluded in 2020 that overall climate change will result in a decline in the intensity and frequency of extreme cold spells, with milder winters reducing fatalities from extreme cold,<ref>{{cite web |title=Climate change impacts of heat and cold extremes on humans |url=https://ec.europa.eu/jrc/sites/default/files/11_pesetaiv_heat_and_cold_sc_august2020_en.pdf |url-status=dead |archive-url=https://web.archive.org/web/20210821182617/https://ec.europa.eu/jrc/sites/default/files/11_pesetaiv_heat_and_cold_sc_august2020_en.pdf |archive-date=21 August 2021 |access-date=25 October 2021}}</ref>{{additional citation needed|date=October 2021}} even if individual cold extreme weather may sometimes be caused by changes due to climate change and possibly even become more frequent in some regions.
According to a 2023 study, "weak extreme cold events (ECEs) significantly decrease in frequency, projection area and total area over the north hemisphere with global warming. However, the frequency, projection area and total area of strong ECEs show no significant trend, whereas they are increasing in Siberia and Canada."<ref>{{Cite journal |last1=He |first1=Yongli |last2=Wang |first2=Xiaoxia |last3=Zhang |first3=Boyuan |last4=Wang |first4=Zhanbo |last5=Wang |first5=Shanshan |date=2023-05-13 |title=Contrast responses of strong and weak winter extreme cold events in the Northern Hemisphere to global warming |journal=Climate Dynamics |volume=61 |issue=9–10 |pages=4533–4550 |language=en |doi=10.1007/s00382-023-06822-7 |bibcode=2023ClDy...61.4533H |s2cid=258681375 |issn=1432-0894}}</ref>