Judging by news reports that we come across every day, it is easy to discern that the world’s climate patterns have changed over the past few years. Rainfall rhythms have gone haywire while drought has also become a regular occurrence, even in places where it used to rain frequently. Flash floods have occurred in countries where even a slight drizzle was rare. There is no easy solution in sight as climate change slowly takes its toll on our world, our only home.
One of the biggest dangers faced by many countries is desertification. It is a slow process in which land productivity and resilience steadily decline. Overgrazing, deforestation and unsustainable agricultural practices are the main causes of desertification. Mining and climate change are also major causes. The fact is that a very large proportion of the world’s rural poor live on degraded lands. This means facing extreme environmental conditions such as, scarcity of water, periods of drought, heat waves, land degradation and desertification. Poverty, lack of socio-economic opportunities, food insecurity, conflicts, weak governance and inadequate policies are other problems they face.
Each year, the Earth is losing 12 million hectares of land and the global forest cover is shrinking by 13 million hectares. According to a UN report, land degradation due to drought and desertification affects about 1.9 billion hectares of land and 1.5 billion people globally. In terms of severity, North America and Africa are the worst off, because nearly three-quarters of their dry lands are affected. Of the world’s dry lands used for agriculture, 70% is affected to some degree by various forms of degradation. In Africa, 60 million people face displacement within five years as their land turns into desert. In fact, two-thirds of Africa’s fertile land could be lost by 2025 due to growing desertification.
But is there a solution ? Desertification is, of course, preventable. But is it reversible ? There is new evidence to suggest that this could be the case. Scientists have considered two things that are found in abundance in deserts.
The sun and the wind. Installing huge numbers of solar panels and wind turbines in the Sahara desert would have a major impact on rainfall, vegetation and temperatures, a new study has found. They found that the actions of wind turbines would double the amount of rain that would fall in the region. Solar panels have a similar impact although they act in a different way.
The scientists modelled what would happen if 9 million sq km of the Sahara desert was covered in renewable energy sources. They focused on this area because it is sparsely populated, and it is also exposed to significant amounts of sun and wind and is close to large energy markets in Europe and the Middle East. According to the authors’ calculations, a massive installation in the desert would generate more than four times the amount of energy that the world currently uses every year.
“Our model results show that large-scale solar and wind farms in the Sahara would more than double the precipitation, especially, in the Sahel, where the magnitude of rainfall increase is between 20mm and 500mm per year,” said Dr Yan Li, the lead author of the paper from the University of Illinois, US.
“As a result, vegetation cover fraction increases by about 20%.” In the Sahel, the semi-arid region that lies to the south of the Sahara, the average rainfall increased by 1.12mm per day where wind farms were present, according to the study. According to the study, with wind turbines, it is all about the mixing of air caused by the rotation of the blades. Wind farms mix warmer air from above, which creates a feedback loop whereby more evaporation, precipitation and plant growth occurs. Solar panels actually reduce the reflection of sunlight from the surface known as the albedo effect. This triggers a positive albedo-precipitation-vegetation feedback that leads to precipitation increases of about 50%, the authors report.
The results ? Precipitation increases predicted by the model would lead to substantial improvements of rain-fed agriculture in the region, and vegetation increases would lead to the growth in the production of livestock, according to Dr Safa Motesharrei, of the University of Maryland, another author of the paper.
This is yet another reason to have more renewable energy power plants instead of fossil fuel plants. Although unwittingly, authorities in Sri Lanka have set up wind and solar farms in some of the driest areas in the country, some of which feature some elements of a desert. Now that there is some evidence of another benefit of these alternative power installations, they should be further encouraged. A study should also be undertaken to check whether these plants have benefitted the soil and stopped land degradation.
However, the best weapon against desertification is still agriculture, especially, the cultivation of various crops that are resistant to extremes of heat and drought. Both, China and India, two countries with a population of over one billion each, have made successful inroads in their battle against desertification through agriculture. In Sri Lanka, the driest areas often produce a spectacular harvest of rice and other crops, thanks to a well-oiled irrigation machine.
One example from China is Minqin, a man-made oasis located between Badain Jaran and Tengger, two large deserts in China, with the area totalling 85,000 square kilometers. In an effort to keep the deserts from converging, a vast haloxylon forest planted by the locals has bound the sand tightly to the ground. The haloxylon species is a sand-fixing plant used abundantly since the 1970s in areas with low precipitation. China has actually reversed the expansion of its deserts. An average of 4,400 square kilometers of desertified land has been restored each year since 2000, according to statistics. “China has created new technologies and practices in the construction of a green homeland,” said Erik Solheim, executive director of United Nations Environment Programme (UNEP). “Not only does it meet domestic needs, but also brings benefits to developing countries.”
Desertification will become a bigger challenge with water getting scarce and land erosion becoming commonplace. By 2025- that’s seven years from today– 1.8 billion people will experience absolute water scarcity, and two thirds of the world will be living under water-stressed conditions. No wonder, that a major United Nations Convention calls drought ‘one of the four horsemen of the apocalypse’.
The world must collectively find solutions for this problem. If the installation of solar panels and wind turbines can indeed halt desertification, it would be akin to killing two birds with one stone – developing countries get renewable power while addressing the threat of desertification. We urgently need global cooperation and a mix of traditional and innovative solutions to contain the threat of desertification.