Editing Tropic of Capricorn (section)

== Geography and environment ==
The Tropic of Capricorn is the dividing line between the [[temperate|Southern Temperate Zone]] to the south and the [[Tropics]] to the north. The [[Northern Hemisphere]] equivalent of the Tropic of Capricorn is the [[Tropic of Cancer]].

The Tropic of Capricorn's position is not fixed, but constantly changes because of a slight wobble in the Earth's longitudinal alignment relative to its orbit around the Sun. Earth's [[axial tilt]] varies over a 41,000 year period from about 22.1 to 24.5 degrees and currently resides at about 23.4 degrees. This wobble means that the Tropic of Capricorn is currently drifting northward at a rate of almost half an arcsecond (0.468″) of latitude, or 15 metres, per year (it was at exactly 23° 27′S in 1917 and will be at 23° 26'S in 2045).  Therefore, the distance between [[Arctic Circle]] and the Tropic of Capricorn is essentially constant moving in tandem. See under [[circle of latitude#Movement of the Tropical and Polar circles|circles of latitude]] for information.

There are approximately 10 hours, 41 minutes of daylight during the June solstice (Southern Hemisphere winter). During the December solstice (Southern Hemisphere summer), there are 13 hours, 35 minutes of daylight. The length of the Tropic of Capricorn at 23°26′11.7″S is 36,788&nbsp;km (22,859&nbsp;mi).<ref>[http://geographiclib.sourceforge.net/cgi-bin/RhumbSolve RhumbSolve online rhumb line calculator] {{Webarchive|url=https://web.archive.org/web/20161203045705/http://geographiclib.sourceforge.net/cgi-bin/RhumbSolve |date=3 December 2016 }}.</ref>

=== Africa ===
In most of this belt of [[southern Africa]], a minimum of seasonal rainfall is reliable and farming is possible, though yields struggle to compete with for example the [[Mississippi basin]], even against like-to-like soil [[fertiliser]]s.  Rivers have been successfully dammed particularly flowing from [[relief precipitation]] areas (high eminences) and those from the edge of the [[Great Rift Valley]], such as the [[Zambezi]], well within the Tropics.  This, with alluvial or enriched soil, enables substantial yield grain farming in areas with good soil.  Across this large region pasture farming is widespread, where intensive, brief and rotational it helps to fertilise and stabilise the soil, preventing run-off and [[desertification]].<ref name=unu>{{Cite web |url=https://ourworld.unu.edu/en/reversing-desertification-with-livestock |title=Reversing Desertification with Livestock – Our World |access-date=7 September 2019 |archive-url=https://web.archive.org/web/20190408221058/https://ourworld.unu.edu/en/reversing-desertification-with-livestock |archive-date=8 April 2019 |url-status=live }}</ref> This approach is traditional to many tribes and promoted by government advisors such as [[Allan Savory]], a Zimbabwean-born biologist, farmer, game rancher, politician and international consultant and co-founder of the [[Savory Institute]]. According to the [[United Nations University]] Our World dissemination he is credited with developing "holistic management" in the 1960s and has led anti-desertification efforts in Africa for decades using a counterintuitive approach to most developed economies of increasing the number of livestock on grasslands rather than fencing them off for conservation.  Such practices in this area have seen success and won generous awards; he gave the keynote speech at UNCCD's Land Day in 2018, and later that year a [[TED (conference)]] address, widely re-broadcast.<ref name=unu/>

{{Gallery
| height       = 141px
| width        = 200px
| File:Tropic of Capricorn (Namibia).jpg
 | A sign marking the Tropic of Capricorn as it passes through [[Namibia]]
| File:Botswana Tropic of Capricorn Sign.JPG
 | A monument marking the Tropic of Capricorn as it passes through [[Botswana]]
| File:SteenbokskeerkringKruger.JPG
 | A monument in [[Kruger National Park]], [[South Africa]]
| File:Tropico del capricorno Madagascar Regione di Atsimo-Andrefana.jpg
 | A sign marking the Tropic of Capricorn in [[Atsimo-Andrefana]] Region, [[Madagascar]]
|File:The Tropic of Capricorn in Mozambique.jpg
 |A sign at the Mozambican line

}}

=== Australia ===
In [[Australia]], areas around the Tropic have some of the world's most variable [[rain]]fall.<ref>[http://journals.ametsoc.org/doi/pdf/10.1175/1520-0442(1999)012%3C3457%3AGPOIRV%3E2.0.CO%3B2 Geographical Patterning of Interannual Rainfall Variability in the Tropics and Near Tropics]</ref> In the east advanced plants such as flowering shrubs and [[eucalyptus]] and in most bioregions grasses have adapted to cope with means such as deep roots and little [[transpiration]]. Wetter areas, seasonally watered, are widely pasture farmed. As to animals, birds and [[marsupial]]s are well-adapted.  Naturally difficult [[Agriculture|arable agriculture]] specialises in dry fruits, nuts and modest water consumption produce. Other types are possible given reliable irrigation sources and, ideally, water-retentive enriched or [[alluvium|alluvial]] soils, especially wheat; shallow irrigation sources very widely dry up in and after [[drought]] years.  The multi-ridge [[Great Dividing Range]] brings [[relief precipitation]] enough to make hundreds of kilometres either side cultivable, and its rivers are widely dammed to store necessary water; this benefits the settled areas of [[New South Wales]] and [[Queensland]].

Behind the end of the green hills, away from the [[Pacific Ocean|Pacific]], which is subject to warm, negative phases of the [[El Niño–Southern Oscillation]] (colloquially this is an "El Niño year/season") is a white, red and yellow landscape of 2,800 to 3,300 kilometres of [[rain shadow]] heading west in turn feature normally arid cattle lands of the [[Channel Country]], the white [[Kati Thanda-Lake Eyre National Park]], the mainly red [[Mamungari Conservation Park]], then the [[Gibson Desert]], after others the dry landscape settlement of [[Kalbarri]] on the west coast and its rest, northward.  The [[Channel Country]] features an arid landscape with a series of ancient [[flood plain]]s from rivers which only flow intermittently. The principal rivers are [[Georgina River]], [[Cooper Creek]] and the [[Diamantina River]].  In most years, their waters are absorbed into the earth or evaporate, but when there is sufficient rainfall in their catchment area, these rivers flow into [[Lake Eyre]], South Australia. One of the most significant rainfall events occurred in 2010 when a monsoonal low from ex-[[2009–10 Australian region cyclone season#Tropical Cyclone Olga|Cyclone Olga]] created a period of exceptional rainfall.<ref>{{cite news |url=http://www.abc.net.au/rural/news/content/201002/s2808740.htm |title=Channel Country rain will boost cattle feed |access-date=18 May 2010 |date=3 February 2010 |work=[[ABC Rural]] |publisher=[[Australian Broadcasting Corporation]] |archive-url=https://web.archive.org/web/20121111052806/http://www.abc.net.au/rural/news/content/201002/s2808740.htm |archive-date=11 November 2012 |url-status=live }}</ref>

El Niño adverse phases cause a shift in atmospheric circulation; rainfall becomes reduced over Indonesia and Australia, rainfall and tropical cyclone formation increases over the tropical Pacific.<ref name="What is an El Niño?">{{cite web|publisher=Australian Bureau of Meteorology |archive-date=18 March 2016 |title=What is El Niño and what might it mean for Australia? |url=http://www.bom.gov.au/climate/updates/articles/a008-el-nino-and-australia.shtml |access-date=10 April 2016 |url-status=live |archive-url=https://web.archive.org/web/20160318103614/http://www.bom.gov.au/climate/updates/articles/a008-el-nino-and-australia.shtml }}</ref> The low-level surface [[trade wind]]s, which normally blow from east to west along the equator, either weaken or start blowing from the other direction.<ref name="What is an El Niño?"/>

{{Gallery
| title        = 
| height       = 140px
| width        = 200px
| captionstyle =
| File:Australia in 1794 Samuel Dunn Map of the World in Hemispheres.JPG
 | Tropic of Capricorn as it runs through Australia in the [[1794 Samuel Dunn Map of the World in Hemispheres|1794 Dunn Map of the World]]
| File:Tropic of capricorn Australia.jpg
 | Road sign marking Tropic of Capricorn in [[Western Australia]]
| File:tropic-capri-australia2.jpg
 | Monument marking the Tropic of Capricorn just north of [[Alice Springs]], [[Northern Territory]]
| File:Tropic of Capricorn monument, Diamantina Developmental Road, 2016.jpg
 | Tropic of Capricorn on the [[Diamantina Developmental Road]], [[Amaroo, Queensland|Amaroo]], [[Queensland]]
| File:Tropic_of_Capricorn_spire_in_Rockhampton.jpg
 | Spire marking Tropic of Capricorn in [[Rockhampton, Queensland|Rockhampton]], [[Queensland]] (4 km north of the actual Tropic of Capricorn)
| File:Longreach at Midday of Summer solstice.jpg
 |Monument marking Tropic of Capricorn near Civic Centre, [[Longreach,_Queensland| Longreach]], at mid-day of [[Summer solstice]] 2019. The monument is few arc seconds south of the Tropic of Capricorn (notice the shadow directly below the sign) 
}}

=== South America ===
In [[South America]], whilst in the continental [[craton]]s soils are almost as old as in Australia and Southern Africa, the presence of the geologically young and evolving [[Andes]] means that this region is on the western side of the subtropical [[anticyclone]]s and thus receives warm and humid air from the [[Atlantic Ocean]]. As a result, areas in [[Brazil]] adjacent to the Tropic are impressively productive agricultural regions, producing large quantities of crops such as [[sugarcane]], and the natural [[rainforest]] vegetation has been almost entirely cleared, except for a few remaining patches of [[Atlantic Forest]]. Further south in [[Argentina]], the temperate grasslands of the [[Pampas]] region is equally influential in [[wheat]], [[soybeans]], [[maize]], and [[beef]], making the country one of the largest worldwide agricultural exporters, similar to the role played by the [[Prairies]] region in [[Canada]].

West of the Andes, which creates a [[rain shadow]], the air is further cooled and dried by the cold [[Humboldt Current]] which makes it very arid, creating the [[Atacama Desert]], one of the driest in the world, so that no [[glacier]]s exist between [[Volcán Sajama]] at 18˚30'S and [[Nevado Tres Cruces|Cerro Tres Cruces]] at [[27th parallel south|27˚S]].<ref>{{Cite web |url=http://hal-sde.archives-ouvertes.fr/docs/00/29/80/60/PDF/cp-3-1-2007.pdf |title=Exposure dating of Late Glacial and pre-LGM moraines in the Cordon de Doña Rosa, Northern/Central Chile (~31°S) |access-date=16 January 2012 |archive-url=https://web.archive.org/web/20140728011357/http://hal-sde.archives-ouvertes.fr/docs/00/29/80/60/PDF/cp-3-1-2007.pdf |archive-date=28 July 2014 |url-status=live }}</ref> [[Vegetation]] here is almost non-existent, though on the eastern slopes of the Andes rainfall is adequate for [[rainfed agriculture]].

{{Gallery
| title        = 
| height       = 140px
| width        = 200px
| captionstyle =
| File:Hito al Tropico de Capricornio (2).jpg
 | Monument marking the Tropic of Capricorn just north of [[Antofagasta]], [[Chile]]
| File:Reloj Solar del Trópico de Capricornio.JPG
 | [[Sundial]] on the Tropic of Capricorn, [[Jujuy Province]], [[Argentina]]
| File:Brasil Tropic of Capricorn.JPG
 | Sign marking the tropic in [[Maringá]], [[Brazil]]
| File:TOC sign Brazil.JPG
 | Marker for the tropic in [[Maringá]], [[Paraná (state)|Paraná]], [[Brazil]]
}}