POZNAN, Poland (AFP) — A 12-day UN conference on climate change began Monday to warnings that the impact of global warming could wreak a dark toll in human misery and conflict.

"The world community is more and more aware that humankind in its activity just reached the limits of the closed system of our planet Earth," said Polish Environment Minister Maciej Nowicki, who is chairing the meeting.

"Further expansion in the same style will generate global threats of really great intensity -- huge droughts and floods, cyclones with increasingly more destructive power, pandemics of tropical disease, dramatic decline of biodiversity, increasing ocean levels," Nowicki said.

"All these can cause social and even armed conflict and migration of people at an unprecedented scale."

The forum of the 192-member UN Framework Convention on Climate Change (UNFCCC) comes half-way in a two-year process, launched in Bali, Indonesia, to craft a new pact to curb greenhouse gases and to help vulnerable countries.

If all goes well, the pact will be signed in Copenhagen in December 2009.

Nowicki urged countries to set aside national interests and "be stimulated by the spirit of compromise."

"We all are equal, we all are children of our Mother Earth," he said.