摘要：Deforestation is a major threat to tropical forests worldwide, contributing up
to one-fifth of global carbon emissions into the atmosphere. Despite protection
efforts, deforestation of tropical forests has continued in recent years. Providing
incentives to reducing deforestation has been proposed in the United Nations
Framework Convention on Climate Change (UNFCCC) Bali negotiations in 2007 to
decelerate emissions from deforestation (REDD—reduced emissions from deforestation
and forest degradation). A number of methodological issues such as ensuring
permanence, establishing reference emissions levels that do not reward business-as-usual
and having a measuring, reporting and verification system in place are essential
elements in implementing successful REDD schemes. To assess the combined
impacts of climate and land-use change on tropical forest carbon stocks in the 21st
century, we use a dynamic global vegetation model (LPJ DGVM) driven by five
different climate change projections under a given greenhouse gas emission scenario
(SRES A2) and two contrasting land-use change scenarios. We find that even
under a complete stop of deforestation after the period of the Kyoto Protocol
(post-2012) some countries may continue to lose carbon stocks due to climate
change. Especially at risk is tropical Latin America, although the presence and
magnitude of the risk depends on the climate change scenario. By contrast, strong
protection of forests could increase carbon uptake in many tropical countries, due to
CO2 fertilization effects, even under altered climate regimes.
