A Democratic lawmaker on Thursday said that she is "not sure" if world leaders can reach an agreement on greenhouses gasses at the U.N. climate conference in Copenhagen.

Rep. Gabrille Giffords (D-Ariz.), a member of the congressional delegation attending the summit, made her remarks on Twitter as President Barack Obama prepared to leave Washington for the Danish capital:

Not sure whether or not a climate agreement can be reached. Time is running out at COP15. Obama +130 heads of state arrive soon.

World leaders at the conference are attempting to forge an agreement on a limit on greenhouse gasses, but tensions between developed nations and China have helped grind the talks to a near stand-still.

China has not yet agreed to transparency, monitoring and reporting standards to which other developing nations have agreed.

Secretary of State Hillary Clinton on Thursday also offering joiuntly contribute with developed nations $100 billion annually to reluctant developing countries in climate finance by 2020.

Obama is expected to give a speech on Friday expressing the United State's willingness to lead on climate change and global warming.

Cross-posted to the Twitter Room