Letter: Woods and sinks

From Richard Tipper, Yadvinder Malhi, Patrick Meir, John Grace and Paul Jarvis, University of Edinburgh

Fred Pearce is critical of plans to create forests to soak up carbon dioxide
as a partial alternative to cutting emissions of the gas
(23 October, p 20).

Few researchers and policy makers have ever suggested that forestry alone
could solve the global warming problem. However, actions such as reducing
deforestation and increasing the planting of trees must be part of the
solution—bearing in mind that emissions from deforestation account for
around 20 per cent of total CO₂ emissions from human sources and equal
more than twice the total greenhouse gas emissions from vehicles.

Many researchers think that the terrestrial carbon sink is likely to
“saturate” within the next 150 years, but others disagree. The uncertainty
regarding sink saturation arises because we simply don’t know enough about the
long-term effects of changes in temperature and moisture on the decomposition of
organic matter in soil.

The important point, however, is the inescapable fact that even if sink
saturation does occur on the global scale, young growing trees will still
accumulate carbon, and eventually store more carbon than other types of land
use. We should also remember that forests provide other environmental services,
ranging from watershed protection to biodiversity preservation.

Finally, most of the important decisions relating to how land use and
forestry are dealt with under the Kyoto Protocol will not be decided in Bonn, as
your article suggested, but next year in Buenos Aires. This will follow
publication in May 2000 of the Special Report on Land Use, Land Use Change and
Forestry by the UN Intergovernmental Panel on Climate Change.