巴斯·弗朗桑 译/贺丛芝

Desertification is a silent， invisible， and slow-burn crisis that is currently destabilizing livelihoods and communities in over 100 countries. Much like climate change， the impacts of desertification are felt first-hand in specific belts of the world. That said， the rest of the world isnt at all immune to the risks， especially second-hand impacts such as social destabilization， migration， food security， and water scarcity.

In an age characterized mainly by biting off more than we can chew on several fronts， the pace of desertification has increased nearly 35 times the historical speed.

What is desertification？

The word itself might bring to mind wind-swept sandy dunes， but， in reality， desertification is a natural phenomenon aggravated to the point that it severely threatens the lives and livelihood of 200 million people worldwide.

Desertification is the process by which fertile land becomes a desert due to natural or human-made causes. The process is natural， but the human causes of desertification have vastly outpaced its natural speed. This decline in biological productivity happens due to a variety of causes， including：

Deforestation

Overgrazing

Climate change

Unsustainable agriculture

Irresponsible irrigation

Flooding and topsoil erosion

Soil pollution

Political and social instability

Desertification not only degrades land in arid and sub-humid areas; it also destroys dryland ecosystems that already exist in deserts， shrublands， and drylands. The rapid global urbanization and land reclamation only serve to aggravate both causes and effects of desertification. Worse， it leaves us with much less land to use for growing food， which—in a world where 95% of nutritious food comes from healthy soil—is a dangerous situation to be in.

The risks of desertification

Pressures on food production systems

Worldwide desertification will have catastrophic effects on food and agricultural systems. As more and more lands become infertile and unavailable for agriculture， the pressures to produce food faster and in higher volumes will increase. Overexploitation of existing lands is a given due to a lack of choice; there will likely also be a spike in the use of chemicals， which will bring down the quality of food produced.

Accelerated deforestation

While deforestation is one of the significant causes of desertification， it is also exacerbated by the process it causes. When lands that were traditionally viable for agriculture decrease in usability， forests， and natural ecosystems will be encroached into. Hectares of forests will be torn down to make space for agricultural land.

Increased social conflicts

In drought-prone and naturally dry areas of the world， desertification has the potential to wreak havoc on the peace and stability of nations. Battles over land and resources will blow up into full-scale wars， much like what is already happening in parts of Asia and Africa that are most vulnerable to the risks of desertification and climate change. Drought and land degradation can trigger a crisis that is then exacerbated by uneven food distribution， lack of access to what is available， and existing poverty and strife.

Higher migration and social pressures

In a bid to move towards greener pastures literally and figuratively， thousands are displaced from their homes on the daily. This mass migration could be internal or international; either way， the envir-onmental and social structures in areas that these migrants choose to settle in can come under severe pressures. This further fans the flame of conflict， inequality， and unsustainable living conditions.

Wider risks to public health

Dropping rates of food security will increase the risks of starvation， malnutrition， and hunger for millions around the world. The rising heat from barren lands and higher temperatures will increase health hazards and infectious illnesses such as dengue and malaria. Unclean water and shortages will increase the chances of water-borne diseases such as cholera and dysentery. In short， desertification poses massive challenges to public health and has the potential to wreak havoc on unsuspecting healthcare systems.

Desertification and climate change

Climate change has the potential to exacerbate desertification， especially in areas that are already vulnerable to shifts in temperature， winds， and solar radiation. The link between the two is a two-way one in that both climate change and desertification pose risks to each other. Additionally， they also form a vicious cycle in that the impact of desertification increases the risks of climate change and vice versa. The relationship is complex， multi-layered， and still under study. However， the known connections between the two phenomena are as follows：

Dry climates mean lower recovery from droughts

Human-induced global warming has wreaked havoc on climatic zones such that dry climates have increased in number and intensity， as have traditionally polar climates. Unprecedented heat waves and drying water bodies overwhelm the vegetations ability to recover from droughts， which results in irreversible degradation and desertification.

Increased rain leads to erosion and flooding

The changing patterns of rain caused by climate change also have much to contribute to the process of desertification. It must be noted that， while climate change has increased the frequency of rain， it has increased the intensity across the world. As a result， low-moisture soil tends to break up and get eroded when it rains heavily， which accelerates the process of desertification. Carbon emissions and pollutants lead to acid rain， which also decreases the quality of soil and food produced.

Rising sea levels mean increased soil salinity

Due to climate change， the seas and oceans of the world have seen an unpre-cedented rise in water levels， especially in tropical and subtropical regions. At the same time， rivers are running dry due to a lack of rainfall—when coupled， these two factors contribute to rising seawater breaching freshwater areas inland. This process has led to soil becoming more saline and less fit for vegetation and this contributes to its desertification in the long run.

荒漠化是一種无声无形、缓慢发展的危机，目前影响着100多个国家人民的生计和社会的稳定。就像气候变化一样，荒漠化的影响在世界上一些特定地区能够直接感受到。但是，其他地区绝非免受其害，尤其是社会不稳定、人员流动、粮食安全和水资源短缺等间接影响。

在这个很多方面都流行贪多嚼不烂的时代，荒漠化的发展速度已经比历史速度增长了将近35倍。

什么是荒漠化？

这个词语本身可能会让人联想到风成沙丘，但实际上，荒漠化是一种不断恶化的自然现象，如今已严重威胁全世界2亿人的生活和生计。

荒漠化是自然因素或人为原因导致肥沃土地变成沙漠的过程。这个过程是自然产生的，但是，人为活动造成的荒漠化已经远远超过了它自然发生的速度。由于以下种种原因，生物生产力不断下降：

滥伐森林

过度放牧

气候变化

不可持续的农业

不负责任的灌溉

洪水和表土流失

土壤污染

政治和社会不稳定

荒漠化不仅会使干旱、亚湿润地区的土地退化，还会破坏沙漠、疏灌丛和旱地现存的土地生态系统。全球城市化加速及土地开垦从成因和后果两方面都加剧荒漠化。更糟糕的是，荒漠化使我们可用来种植粮食的土地大大减少。世界上95%的营养食物都产自健康的土壤，鉴于此，这种情况十分堪忧。

荒漠化的危害

粮食生产面临压力

全球荒漠化会对粮食和农业系统造成灾难性的影响。越来越多的土地变得贫瘠，无法用于农业生产，粮食生产提速增产的压力随之增加。没有足够的土地，就必然会过度开垦现有土地，也有可能会大量使用化学物质，从而降低粮食质量。

滥伐森林加速

滥伐森林是荒漠化的一个重要原因，又因其后果而加剧。当传统上可用于农业生产的土地可用性下降时，森林和自然生态系统就会被侵占。大片的森林将被破坏，改作农业用地。

社会冲突加剧

在易干旱及自然干旱地区，荒漠化可能会对国家的和平与稳定造成严重破坏。对土地和资源的争夺会升级成全面战争，就像亚洲和非洲一些地区已经发生的情况一样。这些地区最容易遭受荒漠化和气候变化的危害。干旱和土地退化会引发危机，而粮食分配不均、可利用资源缺乏以及现有的贫困和冲突又会加剧危机。

人员流动和社会压力倍增

为了迁往更加绿色的牧场——不管是从字面意义还是象征意义来说——每天都有成千上万的人背井离乡。这种大规模人员流动可能是在国内，也可能是跨国。不管怎样，这些移民选择定居的地方在环境和社会结构方面都会面临巨大压力。这进一步加剧冲突、不平等以及生活环境的不可持续。

公共卫生风险加大

粮食安全指数下降将使世界上成百上千万人遭受饥饿、营养不良、饥荒的风险加大。贫瘠土地散发的热量上升，加之气温升高，会扩大健康风险，导致登革热、疟疾等传染病增多。水源不干净、水资源短缺会增加霍乱和痢疾等水媒疾病的发生率。简而言之，荒漠化对公共卫生构成巨大挑战，并有可能压垮毫无风险意识的卫生保健系统。

荒漠化与气候变化

气候变化有可能加剧荒漠化，特别是在那些易受温度变化、风和太阳辐射影响的地区。这两者之间的关系是双向的，气候变化和荒漠化相互构成危害。不仅如此，它们还形成了一种恶性循环，荒漠化造成的影响加剧气候变化的危害，反之亦然。这种关系是复杂且多层次的，目前尚在研究。不过，这两种现象之间已知的关联包括以下几个方面：

气候干燥降低从干旱中恢复的能力

人类活动引起的全球变暖已经对多个气候带造成了严重破坏，干燥气候的数量和强度都在增加，传统的极地气候也是如此。前所未有的酷热和水体干涸抑制了植被从干旱中恢复的能力，导致不可逆转的退化和荒漠化。

降水增加导致水土流失和洪水泛滥

气候变化引起降水模式改变，对荒漠化进程也产生很大影响。需要指出的是，气候变化不仅增加了世界各地降水的频率，同时也加大了降水强度。结果，湿度低的土壤在大雨时容易散落流失，致使荒漠化进程加速。碳排放和污染物会导致酸雨，这也会降低土壤及其产出粮食的质量。

海平面上升加重土壤盐渍度

由于气候变化，全球海洋水位出现前所未有的上升，尤其是在热带和亚热带地区。与此同时，因为降水量不足，河流正在干涸。这两个因素综合作用，海平面上升导致海水侵入内陆淡水区域。这一过程导致土壤盐分增加，越来越不适合植被生长，长远来看，这会造成荒漠化。                          □

（译者为“《英语世界》杯”翻译大赛获奖者）