A/HRC/10/61 page 6 Response measures: mitigation and adaptation 12. Mitigation and adaptation are the two main strategies to address climate change. Mitigation aims to minimize the extent of global warming by reducing emission levels and stabilizing greenhouse gas concentrations in the atmosphere. Adaptation aims to strengthen the capacity of societies and ecosystems to cope with and adapt to climate change risks and impacts. 13. Reaching an agreement on required global mitigation measures lies at the heart of international climate change negotiations. Article 2 defines the “ultimate objective” of the Convention and associated instruments as “the stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system”. A key question is to operationally define the term “dangerous”.12 14. Over the past decades, scientific studies and policy considerations have converged towards a threshold for dangerous climate change of a maximum rise in global average temperature of 2º C above the pre-industrial level.13 Staying below this threshold will significantly reduce the adverse impacts on ecosystems and human lives. It will require that global greenhouse gas emissions peak within the next decade and be reduced to less than 50 per cent of the current level by 2050. Yet, even this stabilization scenario would lead to a “best estimate” global average temperature increase of 2° C - 2.4° C above pre-industrial levels.14 Moreover, the possibility of containing the temperature rise to around 2°C becomes increasingly unlikely if emission reductions are postponed beyond the next 15 years. 15. Adaptation and the financing of adaptation measures are also central in international climate change negotiations. Irrespective of the scale of mitigation measures taken today and over the next decades, global warming will continue due to the inertia of the climate system and the long-term effects of previous greenhouse gas emissions. Consequently, adaptation measures are required to enable societies to cope with the effects of now unavoidable global warming. Climate change adaptation covers a wide range of actions and strategies, such as building sea defences, relocating populations from flood-prone areas, improved water management, and early warning systems. Equally, adaptation requires strengthening the capacities and coping mechanisms of individuals and communities. 12 While UNFCCC does not include specific greenhouse gas reduction targets, its Kyoto Protocol assigns legally binding caps on greenhouse gas emissions for industrialized countries and emerging economies for the period 2008-2012. The Protocol entered into force in 2005 and has to date been ratified by 183 parties to UNFCCC. 13 14 See IPCC AR4 Working Group III (WGIII) Report, pp. 99-100. Four other scenarios of higher stabilization levels estimate the likely temperature increases in the range of 2.8º C to 6.1º C, IPCC AR4 WGIII Report, pp. 227-228.