For months now, expectation has been building that this week's G8 summit in Italy (8-10 July) would make real progress on the headline political issues that need resolving ahead of a UN climate deal. This expectation had been created by the Obama administration, which pushed for the fringe meeting on climate change. But the hopes of the watching world look set to be dashed.

Media reports are already beginning to trickle out on the planned outcome of the meeting. The indications are that the major economies will fail to resolve any of the major political sticking points.

Chief among these sticking points are: (1) a decision on the medium-term (until 2020) climate change mitigation measures and how the responsibility for meeting the implied emissions reduction targets will be divided (notably between industrialised countries); and (2) how to finance climate change mitigation and adaption efforts in developing countries. Unless these headline issues are resolved, there will be no deal on post-2012 global climate policy when the UNFCCC meets at the COP15 in Copenhagen in December.

Instead, the G8 and other major economies are expected to agree on a declaration setting broad goals for global climate policy.

If media reports are to be believed, this will include a rather vague commitment to ensuring a peak in global greenhouse gas emissions by 2020. It could also broadly endorse the scientific recommendation to avoid global warming of more than 2 degrees.

While this goal is consistent with what the scientific consensus agrees is necessary to give us a 50% of preventing dangerous global warming, it ignores the key question of 'how' i.e. how medium-term emissions reductions targets should be distributed in the context of a UN climate agreement.

It had been hoped that the G8 summit would address this question of 'how'. The failure to address is an ominous portent for the UNFCCC talks.

The declaration is also set to include a commitment on a long-term global emissions reduction target of 50% by 2050, with an 80% reduction by industrialised countries. However, reportedly it will fail to include a base year from which to calculate this reduction, which makes the target effectively meaningless (an 80% reduction in emissions based on 2005 levels is vastly different to an 80% reduction based on 1990 levels - 1990 being the base year recommended by the IPCC). In any case, the G8 had already agreed on the 50% target without a base year at a previous meeting.

After all the hype that had been made about this week's G8 meeting, such an outcome would clearly be a major disappointment. It is hard to see where else along the 5-month road to Copenhagen the important political sticking points could be resolved.