WASHINGTON, Muharram 21, 1436, Nov 14, 2014, SPA -- The United States is giving $3 billion to a United Nations fund to help poorer vulnerable countries prepare for a changing climate and develop cleaner energy. President Barack Obama is to announce the contribution at meeting of world leaders in Australia, according to AP. The United Nations is trying to raise at least $10 billion to help developing nations adjust to rising seas, warmer temperatures, and more extreme weather. It also would help the nations come up with energy sources that limit or reduce heat-trapping carbon dioxide emissions from coal, oil and gas. The American pledge would be the biggest to date and would double contributions to $6 billion, according to international environmental groups. In 2008, then president George W. Bush pledged $2 billion to a similar fund. -- SPA 21:05 LOCAL TIME 18:05 GMT www.spa.gov.sa/w