Clinton to attend Rio+20 conference

U.S. Secretary of State Hillary Clinton speaks during a joint news conference with the Turkish Foreign Minister Ahmet Davutoglu (unseen) during the Global Counterterrorism Forum in Istanbul June 7, 2012.

SAN FRANCISCO, June 13 (Reuters Point Carbon) - Secretary of State Hillary Clinton will lead a delegation of officials to the United Nation's sustainability conference in Rio de Janeiro from June 20-22, the State Department said Tuesday, signaling a stronger U.S. commitment to the summit.

The announcement comes after U.N. Secretary General Ban Ki-moon in April called on U.S. President Barack Obama to attend the conference and to take a more active role in global efforts to curb climate change.

Environmental NGOs had hoped Obama would participate to lend weight to the conference.

Environmental Protection Agency (EPA) Administrator Lisa Jackson will serve as alternate head of the U.S. delegation with special envoy on climate change Todd Stern as chief negotiator

Over 130 heads of state and government have confirmed their attendance at the Rio+20 summit, which Ban has said will be one of the biggest conferences in U.N. history.

Ban and others believe the outcome of the conference will serve as the building blocks for a future international climate deal.

Rio+20 will aim to agree non-binding sustainable development goals in areas such as food security, water and energy.

However, expectations to the summit are low as many governments have played down potential outcomes of the meeting and are focusing instead on solving economic difficulties.

(Reporting by Rory Carroll)