Restoration and strict controls help a saltwater marsh in China to absorb greenhouse gases.

A restored and carefully managed wetland on the Chinese coast is a much larger carbon sink than a natural marsh nearby.

Since 1970, 35% of global wetland habitat has disappeared, largely owing to human activity. Researchers say that wetlands restoration is crucial for both maintaining biodiversity and combating climate change.

Jianwu Tang at the Marine Biological Laboratory in Woods Hole, Massachusetts, Xuechu Chen at East China Normal University in Shanghai and their colleagues measured the flows of three powerful greenhouse gases — carbon dioxide, methane and nitrous oxide — in two coastal marshes in Shanghai. The first marsh was relatively untouched; the second had been restored by planting local vegetation and installing erosion controls.

The team found that the rehabilitated wetland took up more carbon dioxide and emitted much less methane than the natural one. As a result, the restored habitat has the net effect of soaking up twice as much carbon as the natural marsh.

The authors call for similar restorations of degraded wetlands to store carbon.

Correction: An earlier version of this article stated that the restored wetland had the net effect of absorbing 13 times more carbon than the natural wetland.