President of the European Commission Jose Manuel Barroso (back row, L) pose for a group photograph with G8 leaders at Gleneagles, Scotland, July 6 2005.

Climate change and global trade will top Thursday's agenda when G8 leaders get down to business in earnest.

The first full day of the G8 summit will be dominated by the environment, an issue which could expose fault lines between the US and other countries.

President Bush has made it clear he will not sign up to Kyoto-style limits on greenhouse gas emissions.

The UK is trying to reach a compromise by stressing commitment to eco-friendly technology to cut greenhouse gases.

Police will be braced for further protests across Scotland after a series of demonstrations on Wednesday resulted in more than 160 arrests.

More than 100 arrests were made near the town of Auchterarder after demonstrators left the agreed route of a march and attempted to penetrate the security cordon around the Gleneagles Hotel.

With up to 4,000 police on duty, the summit is at the centre of the biggest security operation in UK history.

For many protesters and observers, the G8 summit is a defining moment in current world politics, amid increased calls for the world's richest countries to act now to help the world's poorest.

Thursday will see the leaders of the world's richest nations - the United Kingdom, United States, France, Germany, Italy, Russia, Japan and Canada - involved in back-to-back meetings, including a working lunch and dinner.

The leaders of China, India, Mexico, Brazil and South Africa, the world's five emerging economies, will join the discussion on climate change while the International Monetary Fund, World Trade Organization and World Bank will also be represented.

Several countries, notably France, are expected to push for an agreement on an action plan to reduce greenhouse gas emissions.

British Prime Minister Tony Blair has acknowledged international differences over the subject of global warming.

But he has insisted he would push hard for a deal on climate change, which he believes is inextricably linked to boosting African countries' share of international trade.

Speaking on Wednesday evening, Chancellor Gordon Brown said it was vital to develop a new strategy to tackle global warming which had the support of countries such as China and India as well as the US.

This should focus on developing fuel-efficient technology and exploring alternative sources of energy.

"President Bush has made a statement saying he accepts global warming is a problem, he accepts that it is partly man-made," Mr Brown told ITV's News at Ten.

"What I think will happen is that the World Bank will be asked to bring together not just America and Europe but the developing countries, particularly China and India."

Another key area of discussion will be the state of the world economy, particularly efforts to reduce global trade barriers.

Anti-poverty campaigners are hopeful the US may make some concessions in this area, curbing cotton and sugar subsidies which critics claim distort world prices and harm producers in developing countries.

However, President Bush has said that reform of US farm subsidies has to be tied to an overhaul of the EU's Common Agricultural Policy.

The G8 leaders will also discuss a range of foreign policy issues including Iraq and the Middle East peace process.

(Agencies)

back-to-back : one after the other（一个接一个的，连续的）

notably : to a notable extent（显著地，特别地）