DUBLIN, Nov 1 (Reuters) - U.S. Treasury Secretary Janet Yellen said the Group of 20 rich nations was just "a few billion dollars short" of a pledge to raise $100 billion a year to help developing nations tackle climate change, and was working hard to close the gap. Yellen said the target number was a five-year average, and said G20 members remained "very strongly committed" to the goal. "We"re very close to it this year. I think we"re only a few billion dollars short this year, and actually working hard, even now, to try to close the gap," Yellen told reporters after a meeting with Irish Finance Minister Paschal Donohoe in Dublin. Yellen said it was clearly necessary to mobilize public and private capital to help developing countries and emerging markets afford the investments needed to meet climate change obligations."This is a very high priority," she said. "We"re very committed to mobilizing the promised and needed capital." Funding is expected to be one of the biggest sticking points at the U.N. climate talks over the coming two weeks in Glasgow, Scotland, alongside carbon pricing. Both issues have been unresolved for years. read more Yellen said she viewed carbon pricing as a very efficient way of adapting policy to deal with climate change and some of President Joe Biden"s climate change policies could involve "at least implicit carbon pricing through trading arrangements, for example, for the electricity sector." She said the United States supported carbon pricing policies already adopted by many European countries and Canada, and was beginning to work closely with those countries to ensure their systems merged appropriately with those of the United States.