The UN climate change summit will open today at Copenhagen, Denmark. Delegates from 192 countries and regions will get together to discuss a new global climate treaty to replace the Kyoto Protocol and push global cooperation on coping with the climate change.

Here is a roundup of the positions of the main players.

America's weak policy

The US is the world's biggest economy. It accounts for a quarter of global Greenhouse gas (GHG) emissions and that share is growing. Its attitudes and actions are crucial to international cooperation on climate change. The Obama administration sees the Copenhagen Summit as an opportunity to restore US influence in the global negotiations.

In 2001, the Bush administration refused to sign the Kyoto Protocol. In 2007 and 2008, Bush hosted three Major Economies Meetings on Energy Security and Climate Change, involving the U.S., Great Britain, France, China and India. The meetings did not yield any practical results apart from displaying the US intention to set up an alternative framework to the UN climate change talks.

Since Obama took office, he has sought to enhance the US role in climate change talks. He included a new energy development plan in his economic stimulus package. In June the house approved a Clean Energy and Security Act. Internationally, the U.S. has pursued close contacts with China, India and other emerging economies, hoping to establish bilateral agreements on clean energy and environmental protection.

On November 24, The US government announced a target to reduce US emissions by 17 percent by 2020. But there are doubts globally about its meaning and practical significance. The US congress failed to complete work on federal legislation on climate change in advance of the Copenhagen Summit. This shows continuing conflict among interest groups in the U.S. and will impact US performance at the summit. Without congressional support, its pledges and commitments risk being empty words like those signed by Al Gore at Kyoto.

EU proposals

Despite the EU's ceaseless effort to strengthen international cooperation on climate change, many of its proposals have been frustrated since the Bali Meeting. EU leaders reached agreement on a climate change package in 2008 to deliver its ambitious 2020 objective of slashing greenhouse-gas emissions and boosting renewable energies by 20 percent. However, the economic slowdown in Europe is a severe obstacle to its realization.

Second, the EU agreed to allocate 150 billion US dollars in 2009 to help developing nations reduce greenhouse gas emissions, but the different economic levels of the EU nations hampered its implementation when cost sharing was discussed. Nine Central and Eastern European countries, with Poland at the lead, proposed that cost sharing should be based on a country's GDP irrespective of its greenhouse gas emission.

Third, the EU intended extend the EU emissions trading scheme (EU ETS) through a third period (2013—2020) and expand its scope. But many commission members applied for exemptions and attempted to revise the trading rules in their own economic interests, which hampered the EU's ambition of establishing a model carbon trading market.