Protesters dumped broken glass outside urging delegates to make real commitments four months after similar talks in Copenhagen.
That produced a politcal agreement to limit global warming to 2 degrees celsius by 2020.
But with the pledges only voluntary, those in the developing world say it is doomed to fail.
“The small islands don’t feel as if anything has changed. It has gotten worse, in fact. Because when you look at the targets that have been put on the table under the Copenhagen Accord, they are pointing to an increase of between 3.5 to four degrees Celsius, so if anything, it’s become worse.”
Poorer nations want to a legally-binding treaty introduced by the end of the year.
The EU backs that call and also says Copenhagen does not go far enough..
But other industrialised countries are less keen with the head of US delegation on Friday praising the deal in Denmark as a signiifcant milestone.