Despite being a political success of sorts, the climate change deal agreed by world leaders in early June falls far short of the mark when it comes to committing to safe future levels of greenhouse-gas emissions.

The German Chancellor, Angela Merkel, deserves respect for negotiating a deal in which the US has agreed to address climate change within a UN framework. But without specifying immediate goals and actions for the world's largest emitters, the 'compromise deal' is a soft substitute for the hard targets that are so urgently needed.

The devil is in the details and, in the case of this agreement, details appear to be sorely lacking. Despite a push from Merkel for a mandatory 50% slash in carbon emissions by mid-century, no targets were agreed to at the G8 Summit. Former US vice president Al Gore has labelled the deal a disgrace disguised as an achievement. Wan Gang, China's Minister for Science and Technology, has criticized the outcome for failing to spell out the responsibilities of individual countries.

As world leaders dither over how to achieve aggressive reductions in CO2 emissions, a paper highlighted in this issue shows that worldwide emissions increased more rapidly from 2000–2004 than was expected from scientists' projections based on the most fossil-fuel intensive scenarios. This trend looks set to continue, with a new report from the Netherlands Environmental Assessment Agency now confirming that China has overtaken the US as the world's biggest CO2 producer. At the same time, carbon sinks, such as the Southern Ocean, are reaching saturation point, with the inevitable consequence that mitigating global warming could prove even more difficult than anticipated.

Despite the 'unequivocal' fact that warming is underway and the rapidly amassing observational evidence in support of the fact, the question of what to actually do about climate change remains unresolved. The outcome of G8, although a move in the right direction, simply fails to recognize the urgency of this question.