巴斯·弗朗桑 譯/賀叢芝

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.

荒漠化是一種無聲無形、緩慢發(fā)展的危機，目前影響著100多個國家人民的生計和社會的穩(wěn)定。就像氣候變化一樣，荒漠化的影響在世界上一些特定地區(qū)能夠直接感受到。但是，其他地區(qū)絕非免受其害，尤其是社會不穩(wěn)定、人員流動、糧食安全和水資源短缺等間接影響。

在這個很多方面都流行貪多嚼不爛的時代，荒漠化的發(fā)展速度已經(jīng)比歷史速度增長了將近35倍。

什么是荒漠化？

這個詞語本身可能會讓人聯(lián)想到風成沙丘，但實際上，荒漠化是一種不斷惡化的自然現(xiàn)象，如今已嚴重威脅全世界2億人的生活和生計。

荒漠化是自然因素或人為原因?qū)е路饰滞恋刈兂缮衬倪^程。這個過程是自然產(chǎn)生的，但是，人為活動造成的荒漠化已經(jīng)遠遠超過了它自然發(fā)生的速度。由于以下種種原因，生物生產(chǎn)力不斷下降：

濫伐森林

過度放牧

氣候變化

不可持續(xù)的農(nóng)業(yè)

不負責任的灌溉

洪水和表土流失

土壤污染

政治和社會不穩(wěn)定

荒漠化不僅會使干旱、亞濕潤地區(qū)的土地退化，還會破壞沙漠、疏灌叢和旱地現(xiàn)存的土地生態(tài)系統(tǒng)。全球城市化加速及土地開墾從成因和后果兩方面都加劇荒漠化。更糟糕的是，荒漠化使我們可用來種植糧食的土地大大減少。世界上95%的營養(yǎng)食物都產(chǎn)自健康的土壤，鑒于此，這種情況十分堪憂。

荒漠化的危害

糧食生產(chǎn)面臨壓力

全球荒漠化會對糧食和農(nóng)業(yè)系統(tǒng)造成災難性的影響。越來越多的土地變得貧瘠，無法用于農(nóng)業(yè)生產(chǎn)，糧食生產(chǎn)提速增產(chǎn)的壓力隨之增加。沒有足夠的土地，就必然會過度開墾現(xiàn)有土地，也有可能會大量使用化學物質(zhì)，從而降低糧食質(zhì)量。

濫伐森林加速

濫伐森林是荒漠化的一個重要原因，又因其后果而加劇。當傳統(tǒng)上可用于農(nóng)業(yè)生產(chǎn)的土地可用性下降時，森林和自然生態(tài)系統(tǒng)就會被侵占。大片的森林將被破壞，改作農(nóng)業(yè)用地。

社會沖突加劇

在易干旱及自然干旱地區(qū)，荒漠化可能會對國家的和平與穩(wěn)定造成嚴重破壞。對土地和資源的爭奪會升級成全面戰(zhàn)爭，就像亞洲和非洲一些地區(qū)已經(jīng)發(fā)生的情況一樣。這些地區(qū)最容易遭受荒漠化和氣候變化的危害。干旱和土地退化會引發(fā)危機，而糧食分配不均、可利用資源缺乏以及現(xiàn)有的貧困和沖突又會加劇危機。

人員流動和社會壓力倍增

為了遷往更加綠色的牧場——不管是從字面意義還是象征意義來說——每天都有成千上萬的人背井離鄉(xiāng)。這種大規(guī)模人員流動可能是在國內(nèi)，也可能是跨國。不管怎樣，這些移民選擇定居的地方在環(huán)境和社會結(jié)構(gòu)方面都會面臨巨大壓力。這進一步加劇沖突、不平等以及生活環(huán)境的不可持續(xù)。

公共衛(wèi)生風險加大

糧食安全指數(shù)下降將使世界上成百上千萬人遭受饑餓、營養(yǎng)不良、饑荒的風險加大。貧瘠土地散發(fā)的熱量上升，加之氣溫升高，會擴大健康風險，導致登革熱、瘧疾等傳染病增多。水源不干凈、水資源短缺會增加霍亂和痢疾等水媒疾病的發(fā)生率。簡而言之，荒漠化對公共衛(wèi)生構(gòu)成巨大挑戰(zhàn)，并有可能壓垮毫無風險意識的衛(wèi)生保健系統(tǒng)。

荒漠化與氣候變化

氣候變化有可能加劇荒漠化，特別是在那些易受溫度變化、風和太陽輻射影響的地區(qū)。這兩者之間的關系是雙向的，氣候變化和荒漠化相互構(gòu)成危害。不僅如此，它們還形成了一種惡性循環(huán)，荒漠化造成的影響加劇氣候變化的危害，反之亦然。這種關系是復雜且多層次的，目前尚在研究。不過，這兩種現(xiàn)象之間已知的關聯(lián)包括以下幾個方面：

氣候干燥降低從干旱中恢復的能力

人類活動引起的全球變暖已經(jīng)對多個氣候帶造成了嚴重破壞，干燥氣候的數(shù)量和強度都在增加，傳統(tǒng)的極地氣候也是如此。前所未有的酷熱和水體干涸抑制了植被從干旱中恢復的能力，導致不可逆轉(zhuǎn)的退化和荒漠化。

降水增加導致水土流失和洪水泛濫

氣候變化引起降水模式改變，對荒漠化進程也產(chǎn)生很大影響。需要指出的是，氣候變化不僅增加了世界各地降水的頻率，同時也加大了降水強度。結(jié)果，濕度低的土壤在大雨時容易散落流失，致使荒漠化進程加速。碳排放和污染物會導致酸雨，這也會降低土壤及其產(chǎn)出糧食的質(zhì)量。

海平面上升加重土壤鹽漬度

由于氣候變化，全球海洋水位出現(xiàn)前所未有的上升，尤其是在熱帶和亞熱帶地區(qū)。與此同時，因為降水量不足，河流正在干涸。這兩個因素綜合作用，海平面上升導致海水侵入內(nèi)陸淡水區(qū)域。這一過程導致土壤鹽分增加，越來越不適合植被生長，長遠來看，這會造成荒漠化。? ? ? ? ? ? ? ? ? ? ? ? ? □

（譯者為“《英語世界》杯”翻譯大賽獲獎者）