" (...)
1.2 CONTEXT FOR THE CONSIDERATION OF POTENTIAL IMPACTS OF GEOENGINEERING ON BIODIVERSITY

Biodiversity, ecosystems and their services (provisioning, regulating, cultural and supporting) are critical to human well-being. They are being directly and adversely affected by habitat conversion, over exploitation, invasive species, pollution and climate change. These in turn are driven by demographic, economic, technological, socio-political and cultural changes (Figure 1.1). Protection of biodiversity and ecosystems means that we urgently need to address the direct drivers of change, as well as giving further consideration to indirect drivers.

Climate change is becoming increasingly important as a driver of biodiversity loss and the degradation of ecosystems and their services. It is best addressed by a rapid and major reduction in global greenhouse-gas emissions, requiring a transition to a low-carbon economy through changes in how energy is produced and used, and in the way the environment is managed. However, international commitment is currently lacking to reduce future greenhousegas emissions at the scale required, with two main consequences. First, serious and possibly irreversible climate disruption is now much more likely within the next 50–100 years;(5,6) second, to potentially avoid that outcome, increasing attention has been recently given to a range of climate geoengineering techniques, as a different, and as yet unproven, strategy. The early motivation for exploring such concepts was, at least partly, that they might offer an alternative to strong emission reductions; however, geoengineering is now primarily considered by its proponents as an additional action, complementing other efforts to limit the magnitude of human-induced climate change.

Assessment of the impact of geoengineering techniques on biodiversity the mandate for this report—requires an evaluation of their potential for both positive and negative effects, in the context of climate changes that are already occurring and their projected trajectories. Future climate conditions will be largely determined by future anthropogenic greenhouse-gas emissions, in turn largely determined by future mitigation policies agreed at the global level. Since global greenhouse-gas emissions are currently continuing to increase at a rapid rate, the main comparisons made here are in relation to a 2–3 fold increase in atmospheric greenhouse gas concentrations compared to pre-industrial levels, with associated projected increases in average global surface temperature of "
CBD Technical Series No. 66
Geoengineering in Relation to the
Convention on Biological Diversity:
Technical and Regulatory Matters
Part I.
Impacts of Climate-Related
Geoengineering on Biological Diversity
September 2012
https://www.cbd.int/doc/publications/cbd-ts-66-en.pdf page 16



"around 3°C–5°C by 2100. The consequences for biodiversity of such climate change scenarios are summarised in Chapter 3 of this report. Other climate projections, based on other emission pathways, are also possible.

The scale and nature of potential geoengineering impacts on biodiversity will necessarily depend on the ‘baseline’ comparison made. Such impacts will also closely depend on the effectiveness, feasibility and implementation scenario for the specific techniques under consideration. The timing of deployment may also be important. Thus the impacts for a potentially rapid-acting geoengineering technique might vary according to whether it is deployed in the near future, i.e. under ‘present day’ climatic conditions, or in (say) 50 or 100 years time, and whether deployment is made slowly or rapidly.

The CBD generic guidance on impact assessment, discussed below, provided a wider framework for this study."
CBD Technical Series No. 66
Geoengineering in Relation to the
Convention on Biological Diversity:
Technical and Regulatory Matters
Part I.
Impacts of Climate-Related
Geoengineering on Biological Diversity
September 2012
https://www.cbd.int/doc/publications/cbd-ts-66-en.pdf page 17