With Speed and Violence Fred Pearce - Global Commons Institute

would speed plant growth and moderate climate change. Instead, "excess
heating is driving the dieback of forests, accelerating soil carbon loss and
transforming the land from a sink to a source of carbon to the atmosphere."
And further north, beyond the tree line, where some of the fastest
warming rates in the world are currently being experienced, fear is growing
about the carbon stored in the thick layers of permanently frozen soil known
as permafrost. The carbon comprises thousands of years' accumulation of
dead lichen, moss, and other vegetation that never had a chance to rot before
it froze. David Lawrence, of the NCAR, reported in 2005 that he expected the
top 3 yards of permafrost across most of the Arctic to melt during the
twenty-first century. This will leave a trail of buckled highways, toppled
buildings, broken pipelines, and bemused reindeer; it will also unfreeze tens
and perhaps hundreds of billions of tons of carbon. As the thawed vegetation
finally rots, most of its carbon will return to the atmosphere as carbon
dioxide. In those bogs and lakes where there is very little oxygen, most of the
carbon will be converted into methane—which, as we will see in the next
chapter, is an even more potent greenhouse gas.
We should not write off the carbon sink entirely. It won't die altogether.
Especially in higher latitudes, warmer and wetter conditions will sometimes
mean that trees grow faster and farther north than before—at least where
plagues of insects don't get them first. Right now, the best guess is that, on
average, forests are still absorbing more carbon dioxide than they release.
Up to a fifth of the carbon dioxide emitted by burning fossil fuels may still be
being absorbed by soils and forests. But the sink is diminishing, not rising as