15. AR4 do IPCC - redução de emissões Cap. 13 do WG III do

32. REDUÇÃO EMISSÕES Regime stringency: linking goals, participation and timing. Under most equity interpretations, developed countries as a group would need to reduce their emissions significantly by 2020 (10–40% below 1990 levels) and to still lower levels by 2050 (40–95% below 1990 levels) for low to medium stabilization levels (450–550ppm CO2-eq) (see also Chapter 3). Under most of the regime designs considered for such stabilization levels, developing-country emissions need to deviate below their projected baseline emissions within the next few decades (high agreement, much evidence). For most countries, the choice of the long-term ambition level will be more important than the design of the emission-reduction regime [13.3]. pág. 90 Sumário Técnico