Women are the great untapped resource that can help the global economy recover and expand, Secretary of State Hillary Rodham Clinton said Friday as the U.S. and 20 other nations pledged to try to lower barriers to women in the workforce.

Clinton and diplomats from 20 Asia-Pacific nations pledged to try to improve women's economic participation, a task Clinton said will take a generation and will mark one of the most profound transformations of the world economy. The agreement is a run-up to the Asia-Pacific Economic Cooperation meeting in Hawaii later this year, which President Barack Obama will attend.

"With economic models straining in every corner of the world, none of us can afford to perpetuate the barriers facing women in the workforce," Clinton said.

Barriers of law and custom mean that women in developing economies may have no right to inherit land or businesses, or less access than men to land and good quality seed, Clinton said. In more developed economies women still earn less than men, and have fewer opportunities, she noted.

She cited private studies to show what could happen if women were afforded fuller economic participation.

A Goldman Sachs report says America's GDP would grow by 9 percent if barriers to women's workforce participation were lowered. Clinton said the increases for European countries that use the euro as their currency would be 13 percent, and Japan's 16 percent.

She cited a Boston Consulting Group survey concluding that women will control $15 trillion in global spending by the year 2014 and be responsible for two-thirds of consumer spending worldwide by 2028.

"There is a stimulative and ripple effect that kicks in when women have greater access to jobs and the economic lives of our countries," Clinton said. She listed greater political stability, fewer military conflicts, more food and better educational opportunity for children.