WASHINGTON, July 9 (Reuters) - G20 countries are responsible for 80% of the world’s carbon emissions and need to take concrete action now, but there are different paths to achieve this besides explicit carbon pricing, U.S. Treasury Secretary Janet Yellen said on Friday. Yellen said in remarks to a G20 climate tax forum in Venice, Italy, that member countries will need to make significant public and private investments and make “difficult economic decisions” to achieve goals of decarbonizing their economies by mid-century. “It’s important that any carbon border adjustment system focus on the degree to which a country’s climate policies reduce emissions, and hence carbon content, rather than focus only on explicit carbon pricing.” (Reporting by David Lawder Editing by Mark Heinrich) Our Standards: The Thomson Reuters Trust Principles.