The earlier post Dirt Nerd alluded to information in a Nat Geo article by Charles Mann, but didn't actually quote that bit.

Dazhai is in a geological anomaly called the Loess Plateau. For eon upon eon winds have swept across the deserts to the west, blowing grit and sand into central China. The millennia of dust fall have covered the region with vast heaps of packed silt—loess, geologists call it—some of them hundreds of feet deep. China's Loess Plateau is about the size of France, Belgium, and the Netherlands combined. For centuries the silt piles have been washing away into the Yellow River—a natural process that has exacerbated, thanks to the Dazhai Way, into arguably the worst soil erosion problem in the world.

The article goes on to describe the consequences of central command for agriculture, which has severely harmed China's land. How bad is the problem?

A new study says almost forty percent of China is losing soil because of wind and water erosion. The Chinese government recently announced the results of a three-year study. The study was the largest of its kind since China became a communist nation in nineteen forty-nine. . .

The researchers say that every year, four and one-half billion tons of soil are washed or blown away. At that rate, they say, grain production in northeastern China could decrease forty percent within forty to fifty years. The country depends on that area for grain; the northeast is often called China's breadbasket.

The research team estimates that erosion has cost China at least twenty-nine billion dollars in economic losses since two thousand. The team also says that seventy percent of China's poor live in areas damaged by soil loss.

Via Philip Small at NSCSS who adds:

China feeds 20% of the world's population on 7% of the world's arable land. Erosion is China's most significant environmental problem, and it is one of longstanding. Exacerbated by desertification, and increasing demands on production, prospects are for erosion to increase in severity.

This is the sort of thing that makes my criticism of the opportunists in Poznan so scathing (mentioned in earlier posts). While they finagle for power and profit - nattering about fantasy agricultural schemes - the world has real problems that are growing rapidly worse. They have cost billions already and that too will increase. Nobody needs to pay China to stop squandering billions in lost production, they would be amply rewarded by the increased value of the land and its continuing production. The same is true for Africa and other developing nations.