英语翻译沙漠,已占大约第四的地球陆地面积,最近几十年已经以惊人的速度增加.扩大desertlike条件的地区,在那儿他们

英语翻译
沙漠,已占大约第四的地球陆地面积,最近几十年已经以惊人的速度增加.扩大desertlike条件的地区,在那儿他们以前不存在被称为沙漠化.据估计,一个额外的能耗的地球陆地面积已威胁到这个过程.
沙漠化是实现稳定主要是通过自然植被的损失以及随后的加速侵蚀的土壤,通过风和水.在某些情况下,土壤疏松吹完全离开,留下一个无情的表面.在其他情况下,较细的粉尘,可以被移开,而粒子累积形成移动山地或者山脊的沙子.
即使在一个地区保持土壤覆盖,减少植被通常会导致亏损的土壤的能力得以大量吸收的水.雨滴的影响松软的土壤日趋转移微小的颗粒细黏土土壤空间,他们制作了密封表面,如此可以很少量的水渗透.吸水率大大降低,因而径流增加,导致加速侵蚀率.逐渐的干燥能力而引起的土壤吸收水分减少导致植被造成更大的损失,所以一个周期的恶化是进步的表面成立.
在一些地区,增加在沙漠地区正在发生很大程度上由于一个趋势,干燥的气候条件.全球气候变暖产生持续渐进增加一些地区的干旱,在过去的几千年.这个过程可以加速随后的数十年内如果全球暖化造成的空气污染严重增加.

The deserts, which already occupy approximately a fourth of the Earth’s land surface, have in recent decades been increasing at an alarming pace. The expansion of desertlike conditions into areas where they did not previously exist is called desertification. It has been estimated that an additional one-fourth of the Earth’s land surface is threatened by this process.
Desertification is accomplished primarily through the loss of stabilizing natural vegetation and the subsequent accelerated erosion of the soil by wind and water. In some cases the loose soil is blown completely away, leaving a stony surface. In other cases, the finer particles may be removed, while the sand-sized particles are accumulated to form mobile hills or ridges of sand.
Even in the areas that retain a soil cover, the reduction of vegetation typically results in the loss of the soil’s ability to absorb substantial quantities of water. The impact of raindrops on the loose soil tends to transfer fine clay particles into the tiniest soil spaces, sealing them and producing a surface that allows very little water penetration. Water absorption is greatly reduced, consequently runoff is increased, resulting in accelerated erosion rates. The gradual drying of the soil caused by its diminished ability to absorb water results in the further loss of vegetation, so that a cycle of progressive surface deterioration is established.
In some regions, the increase in desert areas is occurring largely as the result of a trend toward drier climatic conditions. Continued gradual global warming has produced an increase in aridity for some areas over the past few thousand years. The process may be accelerated in subsequent decades if global warming resulting from air pollution seriously increases.