The “War” between People and Sand

When talking about desert， we often associate it with the image of barren scenes and sand storm， with nothing useful. It is also often mixed with another word "desertification". Actually， things often have two sides. Only when we have a proper understanding of them， can we avoid the disadvantages and absorb good ones thus making a benefit to mankind.

Where can desert settle

Desert， generally refers to barren areas the surface of which is fully or partially covered by quicksand， with rare plants and air dry. Four out of five continents inhabited by people on the earth， have deserts distributed. Affected by climate， desert concentratedly distributed between 15 ° to 35 °in the south and north latitude. The deserts in Southern Hemisphere start from Kalahari， Namib Desert of the Atlantic coast， across the Indian Ocean， go through the Australian desert， across the Pacific to the Atacama desert in South America； while the deserts in the Northern Hemisphere began from the Sahara desert of Atlantic coast， cross the Suez Canal， the Red Sea， through the Arabian desert， then Thar desert extending in Iran， Afghanistan and India， across the Pacific， to the southwest of North America. Deserts in our country and Central Asia， due to the impact of the Tibetan Plateau uplift， are moved northward， between north latitude 35 ° ～ 50 °.

Deserts contribution

In people's old concept， sand storm is a serious natural disaster， with a strong destructive effect. It often results in poor soils and increases desertification； farmland， houses and roads are buried and facilities are destroyed； it will cause air pollution and the illness and death of human and animals...... However， the same sand storm also contributes for the human thrive.

Fertile ground created by wind

Long before the emergence of human civilization on Earth， the wind carried sand tirelessly thus creating on land fertile soil suitable for plant growth. China's Loess Plateau was created by sand piled of the northwestern deserts and Central Asian inland deserts as well as Gobi deserts for 250 million years in the Northern Hemisphere， which then has become the cradle of Chinese civilization.

Dust in the wind is rich in nutrients required for plant growth. From March 20 to 22 in 2002， a large sand storm swept through Beijing and brought the soil a lot of natural and effective physical and chemical fertilizer to enrich the soil with nitrogen， phosphorus， potassium， calcium， magnesium， boron and other elements for plant growth， and hence improving the increasingly degraded soil.

Make a Supply to marine life across the sea

When the dust goes across the sea， some deposit to the ocean with air， providing nutrients for marine life. Nitrogen and Phosphorus among them can significantly promote the marine primary productivity， while high-intensity input may result in outbreaks of phytoplankton growth. In addition， roughly 20 percent of the global ocean area is water with high nutrition and low-chlorophyll. In these waters， iron is the main limiting factor for phytoplankton photosynthesis. The dust aerosol containing a lot of iron deposits into the sea and promotes the primary productivity of the ocean. It is so called "iron fertilizer effect." More than 50% of the photosynthesis on the earth is carried out by marine phytoplankton. The increase of phytoplankton， not only provides additional food source for other marine life， but fixes more carbon， thereby reducing the concentration of carbon dioxide in the atmosphere as well as reducing the greenhouse gases to mitigate the effects of global warming.

Play amid the clouds regulating climate

Dust has also other impacts on climate change. For example， dust floating in the atmosphere plays the role of a giant parasol during the day. It covers the sun so that the ground temperature decreases， slowing global warming， which is the "umbrella effect"； Dust aerosols as cloud condensation nuclei or ice cores， by interacting with the cloud， change the physical characteristics， optical properties， life cycle and cloud cover of cloud and increase regional precipitation， which is called the "ice nucleation effect."

React with acid and reduce pollution

Carbonate and soluble salt carried by dust is an important source of alkaline carbon stocks. Their hydroxyl ions can make the neutralization effect with large amounts of acidic ions in the atmosphere emitted by industry， thereby reducing the acid deposition by pollutants dissolved in the acid rain and snow. This is called "neutralize acid rain effect" of dust. In the South and North， the industrial acidic pollutants are roughly equivalent， but acid rain is mainly seen in the south of the Yangtze River while in the North， it only scatters. Expert analyzed that the north dust weather contributes a lot.

Great beauty among desolate desert

Sometimes spectacular desert scenery is amazing and makes people fascinated. For example， Badain Jaran Desert described as " the curve painted by God painting " shows a forceful and desolate beauty with sand hills which shapes like waves. Cen Shen ， a poet in Tang Dynasty once wrote “The yellow sand extends to the western coast while various plants grow prosperously to the North”； Wang Wei also vividly described the magnificent scenery of the desert beyond the Great Wall as " Straight lonely smoke rises in the desert， Grand long river reflects the round sun sets. ".

Sahara Desert in Africa across the Atlantic， it provides a wealth of nutrients for Amazon rainforest located in South America. The latest estimate by scientists says that every year， about 27.7 million tons dust of Saharan Desert will be blown to the Amazon basin. Approximately 22，000 tons of Phosphorus contained has greatly nourished the soil of Amazon rainforest.

Terrible Desertification

Desertification refers to the degradation of arid area， semi-arid and sub-humid arid areas caused by a variety of climate and human forces. After the industrial revolution， under the power of machine， people achieved the rapid increase of productivity and experienced population explosion. People changed the attitudes towards nature and redraw the natural look as they wished. The forgiving nature did not spoil the young man， but spoke with the facts tirelessly， reminding mankind to regulate their behaviors. The improper acts of human exacerbated desertification therefore there has been a series of ecological and environmental problems， such as water and soil erosion， loss of biodiversity， drought， water shortage， global warming， and aggravate disasters etc， bringing a serious threat to the social stability and ecological security in arid areas.

In many ecological and environmental problems facing humanity today， the desertification is the most serious disaster. For people threatened by desertification， it means that they will lose the basis of survival. In the 21 countries in sub-arid desert region， over 35 million people were affected in the peak period of drought occurred in the 1980s and more than 10 million people left their homes and becoming "eco-refugees". Desertification is no longer a purely ecological problem， but evolves into economic and social problems. Desertification brought to mankind poverty and social unrest.

At present， China is still faced with severe sandstorms， which has become the scourge of the Chinese nation. It has two characteristics： First， it has a large base and wide distribution. China has more than 1.7 million square kilometers of desertified land to deal with and more than 300，000 severely desertified land which needs urgently governance； except Hong Kong， Macao， Taiwan and Shanghai， all the other provinces， autonomous regions and municipalities are distributed. Second， the desertification degree is heavy with deep harm. The degree of over 70% is becoming moderate or above which is very difficult to handle； sand buried rail， road and canal， which has threatened the safety of towns， villages， pastures and farmland. Sandstorm and other disasters often occur.

Measures taken to combat desertification in China

According to approved "national anti-desertification plan （2011-2020 years）" by the State Council， to 2020， more than half of the desertified land nationwide can be managed and complete the task of managing 20 million hectares desertified land， to further improve the ecological status of sandy area . Specific objectives and tasks are： Plan sealed desertified land conservation areas and increase the anti-desertification efforts of key projects. A comprehensive way to protect and increase the vegetation has to been taken. Meanwhile， we need to actively prevent desertification and make a comprehensive effort to manage desertified land.

Our practice to combat desertification e can be traced back to the 1950s. Especially in the past 30 years， through the implementation of the "Three-North Shelterbelt" project （1978）， the National anti-desertification project （1990）， Beijing and Tianjin sandstorm source control project and reforestation Project （2000） and a series of ecological management projects， about 20% of desertified land has been effectively managed and repaired. The desertified land expansion trend has been effectively curbed. Over the past 10 years， desertified land shows a negative growth.

Is haze and dust related？

Approximately 10% of the particles in the haze is dust-related. It varies in different countries. Regarding sand management， if the dust source is controlled well， haze will also lessen and more significant reduction will be seen in dust storms. Taking Beijing and Tianjin sandstorm source control project as an example， over 10 years， the vegetation coverage rate has increased by 4 percentage points and desertified land has reduced by 30%； there is an obvious decline in the sandstorm weather and strong sandstorms have rarely occurred.

If there is no dust in the world， then there is no Loess Plateau in our country. Therefore， there will be no vast Huang-huai-hai Plain； not to mention that there will be no existence of the endless sea creatures and the seafood we enjoy every day； the green sheen of Amazon rainforest is lost as well. This is really so called " created by god， deserts contribute a lot； created by humankind， deserts harm a lot"！

Edited by Li Jingmin