The issue: The G8 will be looking for progress to tackle global warming after Kyoto expires in 2012. It will need to reverse the rise in carbon emissions in the northern hemisphere and reduce reliance on fossil fuels.
The likely sticking points: America favours investment in nuclear and new technologies. Other countries see the need for further curbs on carbon emissions twinned with clean technology, including renewable energy, such as wind power.
The likely outcome: France, Germany, the UK and Russia are confident of a breakthrough but Mr Bush says he will not support a new Kyoto-style agreement. The G8 may have to settle on a "talking shop" forum for industrialised countries.
The issue: Helping African nations to trade their way out of poverty will be an important issue at the G8. Trade barriers are blocking African goods, and farm subsidies in the US and EU make it difficult for third-world farmers to compete.
The likely sticking points: The US says it will scrap subsidies for its farmers if the EU does this first. Since M.Chirac has in effect blocked movement on CAP reform, an impasse is on the cards. Tony Blair called last week for the CAP to be abolished.
The likely outcome: Wholesale scrapping of trade barriers or farmers' subsidies in the West is a practical impossibility. But there may be some progress here, and possibly the establishment of new targets to help African farmers.
The issue: African nations are strangled by £170bn of debt incurred by previous regimes. Campaigners want the debt cancelled to enable the governments to invest in health and education, rather than interest payments.
The likely sticking points: Gordon Brown says he has already secured a £25bn deal to write off debt for the poorest African countries, and is after a deal to wipe out debt for other countries. President Bush will not support such an aid deal.
The likely outcome: Deal likely to be struck but some Third World charities will be disappointed unless at least 62 poor countries, instead of 19, benefit from debt relief.
The issue: A massive aid package for African nations is a key demand of anti-poverty campaigners, bolstered by the Live8 concert. They want $50bn (£28bn) of new aid to poor countries immediately - including Africa.
The likely sticking points: Rich countries are reluctant to provide extra cash without guarantees of good governance so aid does not disappear into the coffers of corrupt regimes. The UK is convinced of the case for more aid but the US is less so.
The likely outcome: Expected to commit $25bn in aid to Africa over five years, less than 0.01 per cent of the combined economic wealth of the richest donors. Oxfam said 55 million children could die if the money is not made available immediately.