1.2.3 Issues related to the implementation of Article 2
Decisions made in relation to Article 2 will determine the level of climate change that is set as the goal for policy and have fundamental implications for emission reduction pathways, the feasibility, timing and scale of adaptation required and the magnitude of unavoidable losses. The emission pathways which correspond to different GHG or radiative forcing stabilization levels and consequential global warming are reviewed in Chapter 3 (see Tables 3.9 and 3.10). The potential consequences of two hypothetical limits can provide an indication of the differing scales of mitigation action that depend on Article 2 decisions: A 2ºC above pre-industrial limit on global warming would implies that emissions peak within the next decade and be reduced to less than 50% of the current level by 2050; a 4ºC limit would imply that emissions may not have to peak until well after the middle of the century and could still be well above 2000 levels in 2100. In relation to the first hypothetical limt, the latter would have higher levels of adaptation costs and unavoidable losses, but carry lower mitigation costs.
Issues related to the mitigation, adaptation and sustainable development aspects of the implementation of Article 2 thus include, among others, the linkages between sustainable development and the adverse effects climate change, the need for equity and cooperation and the recognition of common but differentiated responsibilities and respective capabilities as well as the precautionary principle (see Section 1.4.1 for more detail on relevant UNFCCC Articles that frame these issues). In this context, risk management issues which take into account several key aspects of the climate change problem, such as inertia, irreversibility, the risk of abrupt or catastrophic changes and uncertainty, are introduced in this section and discussed in more detail in Chapters 2, 3 and 11.
1.2.3.1 Sustainable development
Sustainable development has environmental, economic and social dimensions (see Chapter 2, Section 2.1). Properly designed climate change responses can be part and parcel of sustainable development, and the two can be mutually reinforcing (Section 2.1). Mitigation, by limiting climate change, can conserve or enhance natural capital (ecosystems, the environment as sources and sinks for economic activities) and prevent or avoid damage to human systems and, thereby, contribute to the overall productivity of capital needed for socio-economic development, including mitigative and adaptive capacity. In turn, sustainable development paths can reduce vulnerability to climate change and reduce GHG emissions. The projected climate changes can exacerbate poverty and thereby undermine sustainable development (see, for example, IPCC, 2007b, Chapters 6, Section 9.7 and 20.8.3), especially in developing countries, which are the most dependent on natural capital and lack financial resources (see Chapter 2 and Stern (2006)). Hence global mitigation efforts can enhance sustainable development prospects in part by reducing the risk of adverse impacts of climate change (see also Chapter 12).