cbd-ts-66-en

Part I: Impacts of Climate-related Geoengineering on Biological Diversity
minimize the disadvantages and risks325, 326, 327 such as the use of monocultures and potentially invasive species.
The CBD is also developing advice for the application of REDD+ biodiversity safeguards (reducing emissions
from deforestation and forest degradation and the role of conservation, sustainable management of forests and
enhancement of forest carbon stocks in developing countries).
In order to maximize biodiversity benefits, ecosystem storage of carbon should be based on an environmental
impact assessment including impacts related to biodiversity and native species. Interventions should also incorporate
resilience to anticipated climate change, and should prioritize climatically-appropriate native assemblages of species.
Where such recommendations have not been followed (e.g., in reforestation projects using non-native species), the
result has often been monoculture plantations which are unable to support viable population of endemic species.328
Impacts on ecosystem services
Increased soil carbon can increase the amount of water retained in the soil, thereby increasing the resilience of
ecosystems and potentially mitigating the water-depleting effects of climate change in arid areas. In addition,
increased soil carbon has the potential to enhance crop productivity. This may reduce the incentive to convert
previously non-agricultural land into agricultural land, and could therefore help to safeguard biodiversity. As
demonstrated by a watershed-scale study in Oregon, USA, increasing carbon storage through the introduction
of land-use policies can benefit a wide range of ecosystem services.329 Moreover, several regional studies have
demonstrated that benefits to ecosystem services such as water regulation, biodiversity conservation, and agriculture,
can result from integrated land-use planning that delivers enhanced CO2 sequestration.330
However, while increased soil water retention (as a result of increased soil carbon) may generally have positive
effects, in some areas, increased water retention could lead to more anoxic conditions, increasing CH4 and N2O
emissions. Moreover, enhanced plant productivity does not necessarily produce positive ecosystem impacts, if fast
growing species are favoured. This could lead to shifts in ecosystem composition, interactions between species,
and changes within food webs.
Risks and uncertainties
Large-scale increases in forest cover can have an impact on both planetary albedo and the hydrological cycle, and
can create a protecting buffer for neighboring ecosystems against floods and other environmental perturbations.
Newly created forests are also likely to emit volatile organic compounds (VOCs), which increase the concentration
of cloud condensation nuclei and therefore affect cloud formation. However, the combined effects of increased
forest cover on the hydrological cycle,331 planetary albedo and cloud cover, and subsequent impacts on biodiversity
and ecosystem services, are currently not well understood.332 This is an area where the need for further research
and assessment has been identified.333
Other key uncertainties relate to which soil types are most suitable for carbon enhancement, to avoid adverse side
effects (e.g. anoxic conditions and methane release). It is also currently unclear how a soil carbon change might
affect the community of species dependent on a particular soil type, and whether biodiversity benefits would
ultimately increase or decrease.
325 Secretariat of the Convention on Biological Diversity (2009a).
326 Secretariat of the Convention on Biological Diversity (2003).
327 CBD COP decision VI/22 Annex and X/33 paragraph 8(p).
328 Ramanamanjato & Ganzhorn (2001).
329 Nelson et al. (2009).
330 The Royal Society (2001).
331 Arora & Montenegro (2010).
332 Anderson et al. (2011).
333 Russell et al. (2012).
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