UN chief Ban Ki-moon on Thursday said he may stage a summit to spur a treaty on climate change as he called for a "Green New Deal" that would both curb global warming and salvage the world economy.

"I'm considering convening a summit-level meeting focussed on climate change at the time of the General Assembly in September," the UN secretary general told reporters on the sidelines of the UN climate talks in Poznan.

Holding the summit would depend on progress in talks to craft a worldwide pact, by December 2009, for stopping the juggernaut of global warming, he indicated.

In a speech earlier, Ban said the world needed "a Green New Deal."

"This is a deal that works for all nations, rich as well as poor. Let us save ourselves from catastrophe and usher in a truly sustainable world."

He argued that "a big part" of the massive stimulus to solve the economic crisis should be devoted to investing in a low-carbon economy -- "an investment that fights climate change, creates millions of green jobs and spurs green growth".

Ban made the keynote speech to start a two-day ministerial level meeting in Poznan, Poland, which wraps up 12 days of talks under the UN Framework Convention on Climate Change (UNFCCC).

He praised new environmental plans by China and US president-elect Barack Obama and appealed to heads of the European Union (EU), locking horns over their own climate pact, to show "leadership".

Negotiations among the 192-member UNFCCC are mid-way through the two-year "roadmap" set down on the Indonesian island of Bali last year.

In Poznan, the talks are meant to provide the outlines of a negotiation blueprint. Throughout 2009, further haggling will take place with the aim of fleshing out a deal that can be signed in Copenhagen next December.

But the more than 11,500 delegates in Poland kept a worried eye on Thursday on events in Brussels, where EU leaders were hunkered down on the first day of a two-day summit tasked with forging the bloc's own climate pact.

The EU programme sets down the most ambitious goals of any advanced economy, including 20 percent fewer greenhouse gas emissions by 2020 compared with 1990 levels, increased use of renewable energy sources and overall energy savings.

But several countries are playing tough, most notably those in the former Soviet bloc that are highly dependent on heavily polluting coal power, as well as Germany and Italy worried about the loss of jobs.

The envisioned Copenhagen treaty will amount to an action plan for curbing greenhouse gases and channelling help for vulnerable countries beyond 2012, when current provisions expire under the UNFCCC's Kyoto Protocol.

It is designed to be the most complex and far-reaching environment deal ever struck -- as it has to be, scientists say.

Studies say climate change is happening and its eventual impact may be even worse than thought, creating human misery on a massive scale as deserts expand, sea levels rise and extreme weather becomes more and more frequent.

But cobbling together a global deal is a tall order, with the complex discussions in Poznan centered on how to share out the commitments and costs of cutting the carbon pollution that stokes global warming.

Rich countries acknowledge their historic role in pushing up global temperatures but they say emerging powers like China and India must also take action.

Developing and poorer nations hit back with the argument that the industrialised world should lead by example, and foot the bill for clean-energy technology and coping with the impact of global warming.

Delegates have complained that making progress in Poznan is difficult while the world waits for Barack Obama to take office as US president on January 20.

But Senator John Kerry, present in Poznan and tasked with reporting back to Obama, said that the United States was "determined to rejoin the world community" on climate change and would lead by example with mandatory emissions caps.

"The way to meet the goal in Copenhagen is to have heads of state pick up this challenge and attempt to meet it. I am confident that president-elect Obama intends to do that," Kerry said.