aridification主要原因是降雨的减少并最终丧失。原因有很多:* *板块构造* *大陆移动从一个位置到另一个地方。这是澳大利亚的一个例子。它曾经是附加到南极洲。比今天也是很多酒鬼,但随着它慢慢移向北进入纬度有少雨和干涸。* * * *造山运动——这是山脉的形成,尤其是在大陆的西部,中断潮湿的空气从海洋流的大洲。在移动山脉的空气必须上升导致雨区域海洋方面的山脉和雨影区山脉的另一边,另一个结果是干燥的土地上的雨影一边山脉。这样的例子是(巴塔哥尼亚沙漠)[1],在阿根廷和北美的沙漠。* * * *火山活动* *过度会导致火山释放过多的二氧化碳,以及其他事件可以提示关于全球变暖的平衡。同样,* * * *火山活动* *过度会导致过度下降,大气中的二氧化碳会导致全球变冷和部分地区降雨量的丧失。 **Changes in Ocean Currents** - can also cause aridification. The changes can be changes in direction which can result in the movement of either warm or cold ocean water which disrupts what was previously there. If the [Gulf Stream][2] were to collapse one of the results would be a significant change in the rainfall patterns over Europe. This would be an example of a [shutdown of thermohaline circulation][3]. **Prolonged changes in [El Niño][4] and [La Niña][5] events** in the Pacific Ocean can seriously disrupt rainfall creating either too much or too little rain various regions. The Indian Ocean has a similar system called the [Indian Ocean Dipole][6]. All this can have serious implications for east Africa, southern Asia, Australia and North and South America. **[Land salinization][7]** occurs when salt from below the surface of the Earth is brought to the surface by excessive land clearing for agriculture and the water rises bringing with the subterranean salt, as has happened in many parts or the world that have cleared land for agriculture. The other cause of land salinization is the over use of irrigation for agriculture, as occurred in [Mesopotamia][8]. All agricultural "fresh" water contains small amounts of salt which accumulates in soil over time. Land salinization results in the loss of vegetation and land cover. Large areas of land salinization have resulted in desertification and aridification of regions. [1]: https://en.wikipedia.org/wiki/Patagonian_Desert [2]: https://en.wikipedia.org/wiki/Gulf_Stream [3]: https://en.wikipedia.org/wiki/Shutdown_of_thermohaline_circulation [4]: https://oceanservice.noaa.gov/facts/ninonina.html [5]: http://www.bom.gov.au/climate/enso/history/ln-2010-12/ENSO-what.shtml [6]: http://www.bom.gov.au/climate/enso/history/ln-2010-12/IOD-what.shtml [7]: https://www.encyclopedie-environnement.org/en/zoom/land-salinization/ [8]: https://en.wikipedia.org/wiki/Mesopotamia