Leaders from around the globe have gathered in Rio de Janeiro for a three-day UN conference on sustainable development.
In opening remarks, UN Secretary-General Ban Ki-moon urged world leaders to commit to sustainable development, warning that time is running out for the planet.
"Here in Rio, world leaders must send a signal that they are committed to a sustainable future; a future that lifts people from poverty, generates dynamic and equitable growth and respects the limits of our planet's finite resources," Ban said. "That is the future we want and it is the transformations we need. Our challenge here in Rio is to bring that vision to life."
Ban called on officials to take actions to improve people's lives while protecting the planet.
"Rio+20 is about people. We must offer concrete hopes for real improvements in daily lives for the poor, for women and young people for future generations," Ban said.
Analysts, however, said expectations were low for the event, known as Rio+20 because of the landmark Earth Summit held in that city two decades ago.
That summit paved the way for a global treaty on biodiversity and the 1997 Kyoto Protocol on greenhouse gases, which is due to expire this year.
However, a 49-page draft agreement for Rio+20 only spells out "aspirations" rather than mandatory goals.
While many leading politicians are attending the event, including the president of France and the Russian and Chinese prime ministers, some high-profile leaders will be missing, including U.S. President Barack Obama and German Chancellor Angela Merkel.
Analysts say many leaders are more focused on the global economic slowdown and the debt crisis in Europe.
Based on reporting by AP, Reuters, and AFP