The UN sustainable development summit in Rio de Janeiro has formally opened with a warning from UN head Ban Ki-moon that progress on the issue is too slow.
The secretary-general told world leaders and other ministers that "words must translate into action".
Ban opened the session with a reference to the historic Earth Summit held in Rio 20 years ago, which spawned UN conventions on climate change, biodiversity and desertification, as well as the Agenda 21 blueprint for sustainable development.
His comments suggested that there were still decisions for the estimated 130 heads of state and government, and ministers from other countries, to take.
However, there has been no indication that any are planning to re-open talks on the agreement that their negotiators concluded on Tuesday, before the high-level talks began.