Erich Pica, president of the Friends of the Earth, called the deal a "sham" that amounted to a repackaging of old ideas supported by industrialized nations.
Pica said so-called rich countries were refusing to either commit to adequate emission-reduction goals or help bankroll efforts by poorer nations to cope with coming changes that they had no role in creating.
"The blame for the failure to achieve a real deal lies squarely on the rich countries whose pollution has caused the climate crisis -- especially the United States." Pica said in a written statement, which also called on the mobilization of citizens to push for "true solutions."
With the future of all humans on this planet at stake, rich countries must muster far more political will than they exhibited here," he said.