So, George Bush has finally decided to get serious about climate change, and set an ambitious target for US policy. That target? Halting growth in emissions by 2025. When the EU is promising a 20% unilateral cut from 1990 levels by 2020 (and 30-40% if other developed nations come to the party), and a need to cut global emissions by 60% by 2050 if we are to avoid dangerous levels of climate change, that looks very unambitious indeed.