By 2050, more than 42 percent of China will be green—that is, if China’s plan to build a 400-million hectare (988-million acre) “Great Green Wall” to block expanding deserts and fight climate change takes root as planned. Launched in 1978 and officially known as the Three-North Shelterbelt Forest Program, the network of artificial forests is slated to stretch 2,800 miles (4,506 kilometers) across 13 provinces in northern China within the next 40 years.

The State Forestry Administration argues that the project will curb soil erosion and “desertification.” Global warming, poor regulations and overgrazing have contributed to the rapid spread of deserts, threatening the livelihoods of 400 million people and creating intense dust storms that blanket cities, according to the China Environment Forum at the Woodrow Wilson Center for International Scholars.

The Great Green Wall is also part of a larger reforestation effort that proponents argue can help China, which became the world’s largest carbon emitter in 2007, combat climate change. According to a September 2010 Inter Press Service article, Chinese scientists claim that the new forests of poplar and white birch trees are better at absorbing carbon than slow-growing native forests.

But critics contend that artificial forests are not a long-term solution. “Forest preservation and reforestation can clearly play an important short-term role in climate change mitigation,” University of Leeds geographer Simon Lewis said in a March 2009 Guardian article. “Of course, forest carbon sinks are no longer-term substitute for reductions in fossil-fuel emissions, as there is not enough land in China or elsewhere to plant enough trees to mitigate emissions and avoid dangerous climate change.”

Others say that planting campaigns mask destruction of natural forests to feed demand for timber. There are almost no old-growth forests left in China, according to the Guardian article. “Tree plantations cannot replace the biodiversity and ecosystem processes and functions of the natural forests,” concluded a working group on forest issues in China, according to a meeting summary published in June 1998 in the Wilson Center’s China Environment Series.

Massive tree planting efforts are also expensive—the Great Green Wall has a price tag of more than $6.3 billion—and can be hard to sustain. “Trees planted as part of campaigns have died due to little subsequent care,” according to a China Environment Forum research brief.

There has also been concern about whether reforested areas are too dry to support trees. An April 2003 article in Wired noted that if saplings do survive, they will “soak up massive amounts of groundwater, which could worsen the problem.”

Dee Williams, an American anthropologist referenced in the Wired article, says the government should promote political solutions to desertification, such as providing incentives to reduce grazing and encourage water conservation and temporary relocate locals from certain areas.

According to its most recent national forest inventory, published in December 2009, China already has 62 million hectares of artificial forest, more than any other country. Since the government established an annual Tree Planting Day in 1979, citizens have planted 56.3 billion trees, including 1.8 billion in 2009, an April 2010 article in the Beijing Review stated.