Soils, especially those in tropical forests, play an important role in absorbing carbon and keeping it out of the atmosphere; the world’s soil currently holds about twice as much carbon as the air. Tropical forests account for about a third of the carbon sequestered in soils worldwide, and a significant portion of that carbon resides in subsoils, buried 20cm to 30cm deep, where it usually spends thousands of years before returning to the atmosphere.
Deforestation leads to soil erosion, and it can change the chemistry that keeps carbon molecules bound to other minerals in the soil. A new study suggests that people have been damaging carbon reservoirs in tropical forests for much longer than we thought.
The Maya began farming in the lowlands of northern Central America around 4,000 years ago. By about 2,500 years ago, the civilization was at its peak, clearing away jungle to make room for farms and cities. Maya civilization began to decline shortly before Spanish conquest brought about a final, massive population crash 500 years ago. Today, the jungle has reclaimed most of the land once farmed by the Maya, and many of their cities now lie hidden beneath dense foliage. But the soil turns out to have a much longer memory.
Source: FS – All – Science – News
Carbon impact of ancient Maya farming may still be felt