The story of China's campaign around the Taklamakan Desert is often told as a great success of tree planting a 3,046-kilometre green belt around one of the most extreme environments in the world. It is an interesting and eye-catching but incomplete description. Beijing hasn't turned the Taklamakan into a forest and the desert has not vanished. It has constructed a perimeter defense to keep shifting sand in check, to provide protection to settlements and infrastructure, and to generate value at the edge of the desert.

The Taklamakan is about 337 thousand square kilometres in size, which is bigger than several countries. Over 95 per cent of its surface is made up of moving sand, and other mountain ranges are located around the basin that keep moisture-laden winds from reaching the area. Cultivating such land with normal forests would use up an incredible amount of water and lead to ecological collapse.

This green belt was not planted in one planting drive, but was completed in November 2024. It was the result of efforts started under China's Three-North Shelterbelt Programme in 1978. It was a highly political closure of the perimeter, but the more interesting story is the engineering techniques that were developed during those 46 years.

One of the simplest has made it one of the more successful. Straw is pressed into the sand in checkered patterns, typically in squares that are about a metre across. Such low barriers are obstacles which prevent the wind from lifting and moving sand above them. Gradually accumulates organic matter and water, enabling drought-tolerant shrubs and grasses to take root.

Planting can follow, after the dune is stabilised. This is the opposite approach used by many widely promoted afforestation initiatives where governments decide if the soil, rainfall and groundwater resources are suitable for saplings before counting the saplings.

The performance of China is amazing, but requires careful reading. The proportion of the country that is covered by national forests has risen from about 10 per cent in 1949 to over 25 per cent today. It has increased from about 1 per cent to about 5 per cent in Xinjiang during the 40 years. Despite this, official statistics still show 26.8 per cent of China's land to be desertified, inching down a bit from 27.2 per cent ten years ago.

The magnitude of the investment and the rate of improvement highlights the challenge of desert restoration. Plants that are planted outside of their natural climate areas may experience high mortality, susceptibility to disease and may deplete the groundwater supply at a faster rate than it is replenished. A landscape that appears green in the early years can have an imbalanced water balance within it.

This is the most significant admonition to come from the Taklamakan project. It's not land that's the currency of desert reclamation, it's water. Hardy shrubs, grasses, tamarisk and native poplar can significantly anchor the sand and require much less water than a dense plantation. Efficiency does not generate new water, as with drip-irrigation systems, small amounts go straight to the plant's roots. It does not add to the supply.

Artificial tree belts may be more vulnerable to the desert than floodwater diversion to restore natural poplar forests along the desert's northern edge. Still, each litre of water used for vegetation will be taken from farms, industries, and expanding settlements. Project success, therefore, must be assessed with groundwater levels and not ceremonial planting numbers, and with longer term maintenance costs.

Now a strong business offer is being thrown into this ecological experiment by China. The solar panels are being used as electricity generating equipment, as well as a sand control instrument. They will slow the wind and provide some shade to the soil, which will help lower evaporation under and between panel rows and provide more desirable conditions for vegetation growth. Crop production and sale, as well as livestock grazing, can supplement income as appropriate in local conditions.

China is to add around 253 gigawatts of solar power by 2030, as it rehabilitates around 7,000 square kilometres of desertified land. That proposed generation is over five times the United States' capacity for solar in a single year, for example.

The business case is strong. Government budgets are essential for desert-control programmes, and these are typically depended on long after the first planting. A solar project creates solar power, lease revenue, construction jobs, solar grid investment, and local jobs. It can transform the upkeep of parks and open space into a useful resource and not a permanent public expense.

There are risks. To gain access to large solar parks, transportation infrastructure is required, in addition to roads, which must be cleaned, watered and protected from abrasive dust. Some plants will thrive in the shade, while others may not. If poorly sited, projects can segment habitats or be the reincarnation of the same bad practice of setting targets for industries over ecological limits. Solar plus restoration is thus not a right, but a model that needs to be tested locally.

Other international campaigns are put into perspective by China's experience. The African Great Green Wall was conceived as a belt of continuous greenery across the Sahel, but is now taking on the form of a patchwork of farms, pasture, and plantings suited to the local environment. Through farmer managed natural regeneration, Niger had remarkable outcomes, instead of importing millions of seedlings to protect the shoots that grew from the existing root systems. Saudi Arabia is increasingly looking towards treated wastewater for its restoration goals, and the UAE is using a blend of mangrove expansion, water technology and highly controlled cultivation.

The lesson for India, in the Thar region, is that it shouldn't do a copy of China's kilometre-by-kilometre approach. There is already experience with shelterbelts, traditional water harvesting, drought-resistant agriculture and community-managed grazing in India. This has the potential to secure roads, farms and settlements using decentralised solar power, native vegetation and scientifically monitored groundwater resources with no attempt to produce forests where they don't exist.