My Science School

The following are some of the ways to tackle desertification

• Limiting global warming


• Sustainable land and water management


• Rotational grazing of livestock, boosting soil nutrients by leaving crop residues on the land after harvest, trapping sediments and nutrients that would otherwise be lost through erosion, and planting fast-growing trees to provide shelter from the wind.


• Applying a combination of traditional practices with locally acceptable and locally adapted land use technologies.


• Creating economic opportunities in dry land urban centers and in areas outside of dry lands.


• Unpacking new possibilities for people to earn a living, such as urban growth and infrastructure, could relieve and shift pressures underlying the desertification processes.


•  Eleven countries in Sahel-Sahara Africa — Djibouti, Eritrea, Ethiopia, Sudan, Chad, Niger, Nigeria, Mali, Burkina Faso, Mauritania and Senegal — have focused efforts to fight against land degradation and revive native plant life to the landscape. The initiative, managed in part by the Global Environment Facility (GEF), plants a line of trees as a sustainable way of regenerating the parkland and serves as an example for other problematic locations.

 

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• Desertification is a significant global ecological and environmental problem with far-reaching consequences on socio-economic and political conditions.


• When land becomes desert, its ability to support people and animals hitherto dependent on it declines sharply. While for humans, this results in agriculture failure, decline in food security, malnutrition and loss of livelihood for wildlife, it could be loss of habitat, biodiversity and food source.


• The economically weak will be the worst hit, according to a study presented at the UNCCD. Approximately 80% of “the worlds’ extremely poor’ live in rural areas and land degradation has become an important factor in rural poverty. Desertification can also cause displacement of millions of people.


• Another impact of desertification is an increase in sand and dust storms. These natural phenomena occur when strong winds blow loose sand and dirt from bare, dry soil. Dust storms can have a huge impact on human health, contributing to respiratory disorders such impact on human health, contributing to respiratory disorders such as asthma and pneumonia, cardiovascular issues and skin irritations as well as polluting open water sources.


• More than 75% of Earth’s land area is already degraded, according to the European Commission’s World Atlas of Desertification, and more than 90% could become degraded by 2050.

 

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• The drivers of desertification include overexploitation of soil for agriculture, inappropriate irrigation, deforestation, land cleaning for human settlement and urban development, and overgrazing by livestock. Increase in wildfires and decline in water table through excessive extraction of groundwater are other factors that cause desertification.


• Climate change (which can be attributed to human activities) is also a major factor behind the increase in desertification. Climate change affects the frequency and magnitude of extreme events such as droughts. In areas that are naturally dry, a drought can have a huge impact on vegetation cover and productivity. As plants die off due to lack of water, the soil becomes bare and is more easily eroded by wind. According to studies, the global area of dry lands is expected to expand as the Earth warms.

 

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Desertification is a type of land degradation, where the water-scare parts of the world such as arid, semi-arid and dry sub-humid areas become a desert eventually. The degradation includes temporary or permanent decline in the quality of soil vegetation, water resources and wildlife.

Soil erosion is one form of land degradation. Soil erosion, which is the gradual breaking down of rock and soil, could be brought about by natural forces such as wind. But it can be exacerbated by activities such as ploughing or deforestation.

Loss of soil fertility is another form of degradation. This can be due to loss of nutrients or decline in the amount of organic matter in the soil. Soil can also from acidification from overuse of fertilizers.

While land degradation has occurred throughout history, the pace has accelerated, reaching 30 to 35 times the historical rate, according to the United Nations. This means, more than 40% of the world’s terrestrial surface area, home to more than 2.1 billion people, is at risk.

 

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One one side, countries around the world are facing threats from usually heavy rainfalls, frequent floods and sea-level rise, and on the other, they experiencing soil erosion and reduced crop yield. The second set of problems, the direct result of a type of land degradation called desertification, was the focus of the United Nations Convention to Combat Desertification (UNCCD), held in New Delhi recently. It brought together representatives from 196 countries who discussed the global issue of land degradation and its outcome. The urgent need for investment in land restoration was highlighted. It was stressed that tackling desertification could help keep the global rise in temperatures below the benchmark figure of two degrees Celsius.

The studies presented during the event pointed out how desertification, working in tandem with climate change, may force up to 700 million people to migrate by 2050.

In India, desertification is believed to have led to the extinction of species such as Indian cheetah and pink-headed duck.

 

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• While fish and mobile invertebrates such as shrimp and crabs migrate out of hypoxic areas, slow-moving, bottom-dwelling creatures such as clams and oysters die after extended exposure.


• It has also been found that fish that flee the potential suffocation may quickly become unconscious and die.


• It was found in a study that low oxygen levels recorded along the Gulf Coast of North America led to reproductive problems in fish involving decreased size of organs, low egg counts and lack of spawning.


• Alteration in marine ecosystem also has socio-economic impact on humans. It affects people whose livelihood depends on fishing.

 

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Dead ones generally occur near areas where heavy agricultural and industrial activity spill nutrients into the water. The excess nutrients, especially nitrogen and phosphorous, cause the rapid growth of microscopic algae called phytoplanktons. This phenomenon is called the nutrients, grow, die and sink to the bottom, where they are decomposed by bacteria. The bacteria inhale the dissolved oxygen in the water as they decompose the phytoplankton. This leads to the depletion of oxygen available to other marine life.

If the phytoplanktons are cyanobacteria, the problem is further intensified they are not consumed by zooplankton and fish. Hence they accumulate in water, leading to the expansion of dead zones. The bacterial degradation of their biomass consumes more oxygen in the water.

While nutrients run-off has been known for decades, researchers say that climate change is making the lack of oxygen worse. As more carbon dioxide is released enhancing the greenhouse effect much of the heat is absorbed by the oceans. In turn, this warmer water can hold less oxygen.

Stratification

The other worrying factor is the possible hindrance to replenishment of oxygen. This happens when the water is warmer than usual. Oxygen in the air and the surface usually gets dissolved in the water below by tides and winds. This helps restore the gas consumed by bacteria. When the temperature of the water is high, less dense water flowing into the ocean from rivers sits on top of salty dense water. This process is called stratification. A barrier is formed between the separated masses of water, hampering the replenishment process.

 

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Dead zones are low oxygen areas in the world’s oceans and lakes. A combination of physical, chemical and biological factors creates dead zones, with nutrient pollution being the major culprit. These nutrients come from the run-off of chemical fertilizers and wastewater.

Hypoxic zones can occur naturally, but scientists are concerned about the areas created or enhanced by human activity.  Excess nutrients that run off land or are piped as wastewater into rivers and coasts can stimulate an overgrowth of algae, which then sinks and decomposes in the water. The decomposition process consumes oxygen and depletes the supply available to healthy marine life.

Dead zones occur in many areas of the country, particularly along the East Coast, the Gulf of Mexico, and the Great Lakes, but there is no part of the country or the world that is immune. The second largest dead zone in the world is located in the U.S., in the northern Gulf of Mexico.

 

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Dissolved oxygen in water is essential for the survival of fish and other aquatic organisms. Levels that are too high or too low can harm aquatic life and affect water quality. There are regions in oceans across the globe where the concentration of dissolved oxygen can be so low that marine animals can suffocate and die, and as a result, these regions are often called dead zones. A new study by the conservation group the International Union for the Conservation of Nature (IUCN) has revealed that the number of dead zones has quadrupled in the last half-century – from only 45 in the 1960s to as many as 700.

Citing climate change and increase in nutrient pollution as the causes, the IUCN has warned that many species of fish, including sharks, tuna and marlin are at particular risk. These fishes are sensitive to low levels of the life-giving gas due to their large size and energy demands.

The report on ocean oxygen loss concluded that deoxygenation is already altering the balance of marine life to the detriment of species across the food chain. The biomes that supports about a fifth of the world’s current fish catch are formed by ocean currents usually bring oxygen-poor water to coastlines. So, these areas are especially vulnerable to even tiny variations in oxygen levels, it said.

On currently trends, oceans are expected to lose 3-4% of their oxygen globally by 2100. Most of that loss is predicated to be in the upper 1,000 mt – the richest part of the ocean for biodiversity.

 

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