Desert greening
Desert greening is the process of afforestation or revegetation of deserts for ecological restoration, sustainable farming and forestry, but also for reclamation of natural water systems and other ecological systems that support life. The term "desert greening" is intended to apply to both cold and hot arid and semi-arid deserts. It does not apply to ice capped or permafrost regions. It pertains to roughly 32 million square kilometres of land. Deserts span all seven continents of the Earth and make up nearly a fifth of the Earth's landmass, areas that recently have been increasing in size.
As some of the deserts expand and global temperatures increase, the different methods of desert greening may provide a possible response. Planting suitable flora in deserts has a range of environmental benefits from carbon sequestration to providing habitat for desert fauna to generating employment opportunities to creation of habitable areas for local communities.
The prevention of land desertification is one of 17 Sustainable Development Goals outlined by the United Nations. Desert greening is a process that aims to not only combat desertification but to foster an environment where plants can create a sustainable environment for all forms of life while preserving its integrity.
Desert greening techniques
When establishing or re-establishing vegetation in desert ecosystems there are many factors to consider before implementing a specific strategy. It is important to account for factors such as the geographical location of the area, amount of annual precipitation, average temperature, soil quality, nutrient availability, native plant and animal life, along with the human impact when aiming to restore a degraded or disrupted desert biome.Planting
Planting strategies in the desert are different from conventional planting practices, especially in the initial stages. Deserts are regions in which annual precipitation is considerably less than the evaporation, making it difficult for plants and animals that are not specialized to the biome to survive. One of the ways to ensure the success of the plant life is that prior to being planted in the desert, plants are often grown first in greenhouses, allowing for root systems to develop. Often the plant species that are planted in desert regions are those that are capable of surviving on limited water and able to withstand the sun's direct rays. However, deserts also vary, with some being hot and dry and others being semiarid, and plants that may survive in a coastal desert might not be able to endure the considerably higher temperatures of hot and dry deserts. Therefore, when planting in deserts as an effort to restore the ecosystem or to create a greener space it is important that the vegetation being planted is suitable to the desert in which it is being planted. Utilizing pioneer desert species like the Acamptopappus shockleyi or Lepidium fremontii, which are native to the Mojave Desert, and halophytes such as Salicornia, contributes positively to desert greening efforts. Planted trees can store water, inhibit soil erosion through wind, raise water from underlying aquifers, reduce evaporation after a rain, attract animals, and cause more rain to fall, if the planted area is large enough. Another method of introducing or re-introducing vegetation to deserts is through seeding which involves the scattering of seeds either manually or aerially depending upon the size of the region undergoing vegetation efforts. Using seeding as a desert greening technique on a large scale requires a longer time for the ecosystem to recover and for the vegetation to establish itself as was seen in the Mu Us Desert. Additionally, there are potential downsides due to the environmental vulnerability and predation by desert animals putting the success of this technique at risk.Landscaping and green infrastructure
With the growth of human population in urban areas that are located close to deserts, ecoscaping has become an important strategy when designing and building infrastructure. Using the National Tree Benefit Calculator software it was established that if Acacia tortilis, Ziziphus spina-christi, and Phoenix dactylifera were planted in a desert city like Doha, this would yield a host of environmental benefits along with economic gains including carbon sequestration, air pollution reduction, lowering of the urban heat index, prevention of storm water runoff and increase in property values. As global temperatures increase, environmental impacts are considerably greater in dry regions with reduced precipitation levels which are vulnerable to desertification. Some of the effects that are beneficial for desert-greening which trees offer can also be provided by buildings that have incorporated architectural elements that allow them to shade exposed walls consequently reducing the heat absorption by the building. Another example of a building designed to offer beneficial effects of vegetation in the desert is the IBTS Greenhouse.Agriculture
also known as desert agriculture or arid farming, refers to the practice of cultivating and growing crops in arid or desert regions where water scarcity and extreme climatic conditions pose significant challenges to traditional agriculture. Desert farming involves employing various techniques with the help of technology to overcome the agricultural limitations imposed by an arid environment. Some common approaches used in desert farming include water management, soil improvement, crop selection, shade and windbreaks, greenhouses and controlled environments. Overall, desert farming aims to maximize the efficient use of water resources while improving soil quality, and planting crops suitable to the environment to overcome the challenges of arid environments. This allows farmers to cultivate crops and sustain agricultural production in regions traditionally considered inhospitable for farming.Greenhouse cultivation also known as greenhouse farming or controlled environment agriculture, refers to the practice of cultivating plants within an enclosed structure called a greenhouse. It is a method of crop production that involves creating a controlled environment to optimize plant growth and protect crops from external factors such as extreme weather conditions, pests, and diseases. In a greenhouse, various environmental factors such as temperature, humidity, light intensity, and carbon dioxide levels can be monitored and adjusted to create ideal growing conditions for plants. This is achieved using various technologies such as heating and cooling systems, ventilation, irrigation systems, artificial lighting, and pest control measures. Greenhouses are typically made of transparent materials like glass or plastic, which allow sunlight to enter while trapping heat inside. This helps maintain a warmer temperature compared to the outside environment, extending the growing season and enabling the cultivation of plants that are not naturally suited to the local climate.
Seawater greenhouses are innovative systems that use seawater to grow crops in arid and water-scarce regions. These greenhouses employ a combination of evaporative cooling, humidification, and desalination techniques to create a controlled environment for plant growth. One prominent example of a seawater greenhouse is the Seawater Foundation. The Seawater Foundation is a non-profit organization that aims to address global food and water scarcity by utilizing seawater greenhouses. Their greenhouse system uses evaporative cooling to create a humid atmosphere for crops while seawater is used for humidification and cooling purposes. Another notable example is the IBTS Greenhouse, developed by Seawater Greenhouse Ltd, the IBTS Greenhouse utilizes seawater to cool and humidify the air inside the greenhouse. It incorporates solar desalination systems to convert seawater into freshwater, which is then used to irrigate the plants. The concept of seawater greenhouses offers several advantages. Firstly, it allows for the cultivation of crops in arid regions with limited freshwater availability, reducing the pressure on traditional freshwater sources. Secondly, the humid and cooler environment created within these greenhouses promotes efficient plant growth, even in hot climates. Lastly, the evaporative cooling process can potentially produce freshwater as a byproduct, contributing to water sustainability. By harnessing the power of seawater and innovative greenhouse technologies, these initiatives are contributing to sustainable agriculture and addressing the challenges posed by water scarcity and climate change.
Water resources management
Water availability
Desert greening is substantially a function of water availability. Water can be made available through saving, reusing, rainwater harvesting, desalination, or direct use of seawater for salt-loving plants. Reuse of treated water and the closing of cycles is the most efficient because closed cycles stand for unlimited and sustainable supply – rainwater management is a decentralized solution and applicable for inland areas – desalination is very secure as long as the primary energy for the operation of the desalination plant is available. In the Sahara Forest Project desalination is carried out by solar stills for the generation of the freshwater. Another technique that is used is cloud seeding which helps in producing precipitation in areas with dryer climates. With the new techniques and latest technology used to produce rainfall in areas that had dryer climates, there are often floods due to the urban infrastructure in those areas being insufficient for precipitation that exceeds conventional levels. Dehumidification is a technique that uses "atmospheric water generation" or air to water, used by the military for potable water generation. However, this technology uses 200 times more energy than desalination, making it unsuitable for large scale desert greening.Collecting rainwater and storing it in ponds, reservoirs, or underground tanks is one of the simplest ways to improve soil moisture content, helping to increase green cover and crop production in arid areas. It is an effective method for increasing water availability in arid regions and can contribute to desert greening in several ways, such as increasing soil moisture so that farmers have a reliable water source for their crops, even during periods of low rainfall. Also, it plays an important role in recharging groundwater, since in many arid areas the groundwater is easily depleted, which could further exacerbate the aridity. This can help to combat desertification, reduce soil erosion, and promote biodiversity. Additionally, it helps alleviate water scarcity in areas with limited access to reliable water sources. Rainwater harvesting can serve as a practical and sustainable solution. It reduces the stress on scarce water resources, such as rivers or underground wells, and it provides a decentralized water supply system. Overall, rainwater harvesting contributes to desert greening by increasing soil moisture, promoting vegetation growth, and conserving water resources. It is a cost-effective and environmentally friendly technique that can be implemented at various scales, from individual households to large-scale agricultural systems to make desert areas more productive and sustainable.