What is the difference between desertification and desertization

Stringer is commenting here in her role at her home institution and not in her capacity as an IPCC author. This is the case with all the scientists quoted in this article. Both natural variability in climate and global warming can also affect rainfall patterns around the world, which can contribute to desertification.

Rainfall has a cooling effect on the land surface, so a decline in rainfall can allow soils to dry out in the heat and become more prone to erosion. On the other hand, heavy rainfall can erode soil itself and cause waterlogging and subsidence. For example, widespread drought — and associated desertification — in the Sahel region of Africa in the second half of the 20th century has been linked to natural fluctuations in the Atlantic, Pacific and Indian Oceans , while research also suggests a partial recovery in rains was driven by warming sea surface temperatures in the Mediterranean.

Dr Katerina Michaelides , a senior lecturer in the Drylands Research Group at the University of Bristol and contributing author on the desertification chapter of the IPCC land report, describes a shift to drier conditions as the main impact of a warming climate on desertification. Climate change is also a contributing factor to wildfires , causing warmer — and sometimes drier — seasons that provide ideal conditions for fires to take hold.

And a warmer climate can speed up the decomposition of organic carbon in soils, leaving them depleted and less able to retain water and nutrients. That overexploitation refers to the way that humans can mismanage land and cause it to degrade. Perhaps the most obvious way is through deforestation.

Removing trees can upset the balance of nutrients in the soil and takes away the roots that helps bind the soil together, leaving it at risk of being eroded and washed or blown away. Deforestation near Gambela, Ethiopia. Forests also play a significant role in the water cycle — particularly in the tropics. For example, research published in the s showed that the Amazon rainforest generates around half of its own rainfall. This means that clearing the forests runs the risk of causing the local climate to dry, adding to the risk of desertification.

Food production is also a major driver of desertification. Growing demand for food can see cropland expand into forests and grasslands , and use of intensive farming methods to maximise yields. Overgrazing of livestock can strip rangelands of vegetation and nutrients. So, while desertification is experienced in particular locations, its drivers are global and coming largely from the prevailing global political and economic system.

Of course, none of these drivers acts in isolation. He tells Carbon Brief:. Naturally, these will have negative impacts on food security and livelihoods, especially in developing countries. This also can mean a loss of biodiversity and visible scarring of the landscape through erosion and the formation of gullies following heavy rainfall.

Degradation can also open the land up to invasive species and those less suitable for grazing livestock, says Michaelides:. Practically speaking, the consequences of this are less available land for grazing, and less productive soils. Ecosystems start to look different as more drought tolerant shrubs invade what used to be grasslands and more bare soil is exposed.

Examples are many countries in East Africa — especially Somalia, Kenya and Ethiopia — where over half of the population are pastoralists relying on healthy grazing lands for their livelihoods. The UNCCD estimates that around 12m hectares of productive land are lost to desertification and drought each year. This is an area that could produce 20m tonnes of grain annually.

This has a considerable financial impact. Loss of livestock, reduced crop yields and declining food security are very visible human impacts of desertification, says Stringer:.

Another impact of desertification is an increase in sand and dust storms. Dust storms can have a huge 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. They can also play havoc with infrastructure, reducing the effectiveness of solar panels and wind turbines by covering them in dust, and causing disruption to roads, railways and airports. Adding dust and sand into the atmosphere is also one of the ways that desertification itself can affect the climate, says Kimutai.

Dust particles in the atmosphere can scatter incoming radiation from the sun, reducing warming locally at the surface, but increasing it in the air above. They can also affect the formation and lifetimes of clouds, potentially making rainfall less likely and thus reducing moisture in an already dry area.

Soils are a very important store of carbon. This process also makes nutrients in the soil available for plants to use as they grow. Soil erosion in Kenya. And typically, respiration declines with decreasing soil moisture to a point where microbial activity effectively stops.

While this reduces the CO2 the microbes release, it also inhibits plant growth, which means the vegetation is taking up less CO2 from the atmosphere through photosynthesis.

Overall, dry soils are more likely to be net emitters of CO2. So as soils become more arid, they will tend to be less able to sequester carbon from the atmosphere, and thus will contribute to climate change. In Africa, two thirds of the soil is deserts or arid zones; in Asia there are 1.

And in Central and South America, one quarter of the soil is a desert or an arid zone. In this map it is possible to see the Iberian Peninsula stained with red and orange dots. In the following map of the Spanish Ministry of Agriculture, Food and Environmentwe can see the endangered areas in detail. Risk of desertification in Spain. We can see that the so called Spanish Mediterranean Arch concentrates the areas with greater risk; in some cases there is already a slow deterioration process, with important areas in the Southeast and South.

In these areas there is the already mentioned climate aggravation, as it rains very little and when it does, it is seasonal rain and very frequently comes as violent downpours. It is easy to understand that the elimination of our bad practices is the key factor to fight desertification. It is essential to pursuit a sustainable agricultural and livestock development.

To that effect, in many occasions it is only necessary to resort to traditional practices that have been abandoned due to demographic pressure and very often to a political mismanagement that has allowed the imposition of single-crop cultivation, altering the ecological balance.

A project that summarises and shows these actions clearly is the one finished by the We Are Water Foundation in in Anantapur, the largest district of the 22 that make up the Indian state of Andhra Pradesh, together with the Vicente Ferrer Foundation: the construction of a reservoir in Ganjikunta.

There, in an area threatened by desertification and subject to the climatic whim of the monsoons, the catchment of rainwater by means of small reservoirs allows farmers to diversify their crops, guaranteeing water in the long drought seasons and recovering the aquifers by filtration, thus providing water to the wells in the area and improving reforestation. Another project of the Foundation that shows how to find solutions in communities threatened by the deterioration of fertile soil is the recovery of the natural water cycle in the Bosawas Reserve, in Nicaragua.

Education is one of the key work areas for the recovery of traditional agricultural and livestock techniques, in order to achieve the sustainability of the economic activity. It is possible to fight desertization, although it is not an easy task. May the threat of its nearness raise our awareness so that we support the initiatives that fight it!

The lost sea Water, the right to a decent life Water for thought. The presence of humans in the equation is what marks the difference. In desertization, the causes of deterioration are strictly natural; but in desertification human activities are also a factor, indeed the determinant one.

Deforestation , in order to plant crops and obtain energy, bad farming practices sewing without rotation, short-term investment horizons, working of unprotected soils during dry periods and poor fertilizer planning , irresponsible water management over-exploitation of aquifers, inefficient irrigation, selection of species unsuitable to local conditions and over-grazing, are some of the causes induced by humans that accelerate the impoverishment of soil.

But climate change , also caused by humans, and the wide-ranging destruction it wreaks, such as drought, fire, erosion, etc. According to the United Nations, over 24 billion tonnes of fertile soil is disappearing every year. Today, two-thirds of the Earth is locked into a process of desertification. This is a surface area equivalent to all the arable land in India.