Drought

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Droughts cause a range of impacts and are often worsened by to the effects of climate change on the water cycle: a dry riverbed in France; sandstorm in Somaliland due to drought; droughts negatively impact agriculture in Texas; drought and high temperatures worsened the 2020 bushfires in Australia.

A drought is a period of drier-than-normal conditions.[1]: 1157  A drought can last for days, months or years. Drought often has large impacts on the ecosystems and agriculture of affected regions, and causes harm to the local economy.[2][3] Annual dry seasons in the tropics significantly increase the chances of a drought developing and subsequent wildfires.[4] Periods of heat can significantly worsen drought conditions by hastening evaporation of water vapour,[5] drying out forests and other vegetation and increasing fuel for wildfires.[4][6]

Drought is a recurring feature of the climate in most parts of the world, becoming more extreme and less predictable due to climate change, which dendrochronological studies date back to 1900. There are three kinds of drought effects, environmental, economic and social. Environmental effects include the drying of wetlands, more and larger wildfires, loss of biodiversity. Economic consequences include disruption of water supplies for municipal economies; lower agricultural, forest, game, and fishing outputs; higher food-production costs; and problems with water supply for the energy sector. Social and health costs include the negative effect on the health of people directly exposed to this phenomenon (excessive heat waves), high food costs, stress caused by failed harvests, water scarcity, etc. Prolonged droughts have caused mass migrations and humanitarian crisis.[7][8]

Many plants, such as cacti, have drought tolerance adaptations like reduced leaf area and waxy cuticles. Some others survive dry periods as buried seeds. Semi-permanent drought produces arid biomes such as deserts and grasslands.[9] Most arid ecosystems have inherently low productivity.

The longest drought in recorded history started 400 years ago in the Atacama Desert in Chile and still continues.[10] Throughout history, humans have usually viewed droughts as "disasters" due to the impact on food availability and the rest of society. People have viewed drought as natural disaster, something influenced by human activity, and as a result of supernatural forces.

  1. ^ Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D.  Jiang, A.  Khan, W.  Pokam Mba, D.  Rosenfeld, J. Tierney, and O.  Zolina, 2021: Water Cycle Changes Archived 2022-09-29 at the Wayback Machine. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I  to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1055–1210, doi:10.1017/9781009157896.010.
  2. ^ Living With Drought Archived 2007-02-18 at the Wayback Machine
  3. ^ Australian Drought and Climate Change Archived 2018-07-26 at the Wayback Machine, retrieved on June 7th 2007.
  4. ^ a b Brando, Paulo M.; Paolucci, Lucas; Ummenhofer, Caroline C.; Ordway, Elsa M.; Hartmann, Henrik; Cattau, Megan E.; Rattis, Ludmila; Medjibe, Vincent; Coe, Michael T.; Balch, Jennifer (30 May 2019). "Droughts, Wildfires, and Forest Carbon Cycling: A Pantropical Synthesis". Annual Review of Earth and Planetary Sciences. 47 (1): 555–581. doi:10.1146/annurev-earth-082517-010235. ISSN 0084-6597.
  5. ^ Merzdorf, Jessica (July 9, 2019). "A Drier Future Sets the Stage for More Wildfires". Climate Change: Vital Signs of the Planet. NASA.
  6. ^ Cite error: The named reference Hartmann was invoked but never defined (see the help page).
  7. ^ Stanke, C; Kerac, M; Prudhomme, C; Medlock, J; Murray, V (5 June 2013). "Health effects of drought: a systematic review of the evidence". PLOS Currents. 5. doi:10.1371/currents.dis.7a2cee9e980f91ad7697b570bcc4b004. PMC 3682759. PMID 23787891.
  8. ^ Bellizzi, Saverio; Lane, Chris; Elhakim, Mohamed; Nabeth, Pierre (12 November 2020). "Health consequences of drought in the WHO Eastern Mediterranean Region: hotspot areas and needed actions". Environmental Health. 19 (1): 114. doi:10.1186/s12940-020-00665-z. ISSN 1476-069X. PMC 7659048.
  9. ^ Keddy, P.A. (2007), Plants and Vegetation: Origins, Processes, Consequences, Cambridge, UK.: Cambridge University Press, ISBN 978-0521864800
  10. ^ "Driest Place: Atacama Desert, Chile". Extreme Science. Retrieved September 25, 2016..