POZNAN, Poland, Dec. 12 (UPI) -- Former U.S. Vice President Al Gore Friday called on world leaders to become more involved in hammering out a global climate deal, amid hopes that the United States will take the lead starting next year.

Gore said heads of state should get "personally involved" by meeting "several times" over the coming 12 months to ensure that an ambitious climate-protection treaty is signed at a U.N. summit in late 2009 in Copenhagen, Denmark.

But before Copenhagen comes Poznan: Delegates from 189 countries are currently in the western Polish city to wrap up the U.N. conference intended to pave the way to more concrete negotiations leading up to and in Copenhagen.

Speaking to a large audience of delegates, NGO officials and journalists at the Poznan conference, Gore urged the world to commit to greater emissions reductions in the face of evidence that unhindered climate change will make the Earth "uninhabitable."

In a demand that drew loud cheers and lengthy applause from the audience, he called on the world's governments to bring down carbon dioxide levels to 350 parts per million -- the amount deemed safe by most experts.

Currently, the atmosphere holds 385 ppm, and the U.N. process looks likely to commit itself to a 450 ppm target. Gore called this goal "inadequate."

The former vice president has been warning of the dangers of global warming for years, long before "most of the world thought it mattered," said Yvo de Boer, the United Nations' top climate official. In 2007 Gore won the Nobel Peace Prize for his campaign to draw attention to global warming, and on Friday here in Poznan he was received like a rock star by environmental activists, virtually all of whom also lobby for the 350 ppm limit.

Earlier this week some 100 youths lay in the rain in downtown Poznan to create the image of a sinking island; organized by the youth group 350.org, the youths have been calling on delegates to fight for a climate treaty that meets the 350 ppm target -- one that is vital for several island states facing extinction from rising sea levels.

Reaching a bold climate treaty is a "moral cause" and a "generational mission" that citizens and governments need to embrace more vigorously, Gore said.

"We need to focus clearly and unblinkingly on this crisis, rather than spending so much time on O.J. Simpson and Paris Hilton and Anna Nicole Smith," Gore said.

While negotiations between the world's governments are ongoing, "we cannot negotiate with the facts, with the truth about our situation, with the consequences of unrestrained dumping" of billions of tons of carbon dioxide into the atmosphere, Gore said.

Yet Gore had some good news as well: Across the world, developing countries are making bolder efforts to stop climate change, he said.

Gore lauded Brazil for stopping deforestation and China for a green economic stimulus of $600 billion over the next two years, as well as "the largest tree-planting program the world has ever seen."

Gore praised local, state and regional climate-protection efforts inside the United States, which, together with the presidency of Barack Obama, will turn Washington into a global leader in climate change, he said.

Delegates in Poznan have huge hopes for a new U.S. administration to turbocharge global climate-protection efforts, and Gore said they wouldn't be disappointed.

"In spite of remaining obstacles, I believe that the causes for hope and optimism are greater than the causes for doubt and discouragement, and I believe the road to Copenhagen is now clear," he said. "To those fearful that it's too difficult … I would say it can be done, it must be done, let's finish this process in Copenhagen."

Just around the time when Gore spoke, EU ministers in Brussels, after some significant bickering, reached an agreement on the body's ambitious and binding climate-protection goals.

The agreement sends a "clear message to the negotiations in Poznan and onwards to Copenhagen that difficult roadblocks can be overcome and resolved," the United Nations' De Boer said.