Hundreds of climate activists are braving cold winds to march through Warsaw to campaign against global warming.

The march Saturday coincides with a two-week U.N. conference that is to prepare the groundwork for a new climate deal expected in 2015.

The march was organized by Poland's small Green Party and has gathered activists from Europe. It is being heavily escorted by police to ensure security.

A banner calls for "Social Justice and Positive Energy for Everyone." German activists with the Friends of the Earth organization are rolling a giant globe and Greenpeace members are walking with a picture of the 30 people arrested in Russia following their protest in the Arctic.