During the last 24 hours of negotiations, a bloc of countries led by Papua New Guinea, with support from the Democratic Republic of Congo and Colombia, have resisted efforts to impose a package of safeguards to ensure the credibility of forest offsets.

The three countries — each with substantial amounts of uncut forests and a questionable ability to oversee them — are objecting to three major provisions, according to Greg Picker, a former member of the Australian climate negotiating team and now a consultant on forest issues to the delegation.

The first of these is the U.N.’s desire to “put boots on the ground” to ensure that trees are actually left standing — in other words, allow inspectors to move freely within a country’s borders to assess the veracity of preservation claims.

The second is to clarify land titles and make sure that those paid for the carbon in the trees actually own the land on which the trees are growing.

The third is a provision that will assess the “permanence” of these preservation efforts.

Papua New Guinea agreed that safeguards were necessary but objected to the presence of international inspectors challenging its national sovereignty.

The country has already been tarred by corruption in setting up early offset projects. In September, the Sydney Morning Herald reported on a $100 million carbon trading scandal involving fake carbon certificates in one of PNG’s preservation deals.

Mark Schapiro specializes in international and environmental stories. His award-winning work appears in all media: in publications such as Harpers, The Atlantic, Mother Jones and Yale 360; on television, including PBS FRONTLINE/World and KQED; on public radio including Marketplace; and on the web. He is currently writing a book for Wiley & Co. investigating the backstory to our carbon footprints. His previous book, "EXPOSED: The Toxic Chemistry of Everyday Products and What’s at Stake for American Power," reveals the health and economic implications of the tightening of environmental standards by the European Union.