Japan and the United States will begin expert-level environmental talks in September aimed primarily at boosting cooperation in the development of technologies needed to better forecast and prevent global warming, government sources said Friday.

The talks will come about two months after Prime Minister Junichiro Koizumi and U.S. President George W. Bush agreed at Camp David, Md., to jointly develop such technologies while addressing other issues related to global warming, a heat-trapping phenomenon widely believed to be caused by emissions of carbon dioxide and other so-called greenhouse gases.

The talks will be conducted separately by three working groups, the sources said. Each group will be jointly headed by deputy bureau chief-level officials from each country, they added.