Quandary over Soviet croplands: Researchers ponder whether Eastern Europe’s large areas of abandoned land should be replanted or left as a carbon sink.

The Soviet Union’s collapse in 1991 heralded the end of many unprofitable communist industries, along with unprecedented changes in land use. As the free-market economy took hold, large swathes of Soviet cropland were abandoned by farmers and reclaimed by nature, causing a headache for today’s policy-makers. Should it be replanted to feed hungry mouths, or left wild to act as a substantial sink for polluting carbon dioxide?