(AP) -- U.N. climate talks moved into their decisive week Monday with the agenda dominated by future cuts in carbon emissions and keeping countries honest about their actions to control global warming.
Government ministers arrived in force to begin applying political muscle to negotiations that in the past week have narrowed some disputes, but which are likely to leave the toughest decisions for the final hours of the 193-nation conference on Friday.
Delegates were feeling pressure to produce at least a modest agreement from the two-week U.N. meeting to restore credibility to the talks after the last summit in Copenhagen failed to agree on any binding action to rein in emissions of global-warming gases.
"We cannot leave Cancun empty-handed," warned Connie Hedegaard, the European Union's top climate official.
The conference seeks decisions on establishing a "green fund" to help poorer nations rein in greenhouse gases and to adapt their economies and infrastructure to a changing climate; an agreement making it easier for developing nations to obtain patented green technology from advanced nations; and pinning down more elements of a system for compensating developing countries for protecting their forests.
New negotiating documents put on the table over the weekend were generally well received, despite criticisms of flaws and omissions.
"These texts cover all the elements for a balanced package, and that is good," said Hedegaard. "We have a basis to work from this week."
But she said negotiators need to nail down ways to ensure that countries meet their emissions pledges. Actions by both industrial and developing countries must be monitored so that "they deliver on their promises," she said. "We must be able to verify that it is actually being done."
Falling short of a legal treaty at last year's summit, President Barack Obama brokered a political document with the leaders of China, India, Brazil and South Africa, called the Copenhagen Accord, which outlined important compromises.
One breakthrough came when China agreed to allow other countries to review climate actions that received international financing. At Cancun, the Chinese went a step further and said all their operations, including fully domestic actions, would be open to international scrutiny.
But details about how this would be done remained to be settled.
Adoption of the Copenhagen Accord was blocked by a handful of dissident nations. In subsequent months, however, 140 countries declared their endorsement of the deal, and 85 of them made specific pledges for reducing carbon emissions, or at least limiting their growth, by 2020.
Mexico's deputy foreign minister, Juan Manuel Gomez Robledo, said more countries had said in private consultations that they intended to add their pledges to the list. And some that already have submitted pledges may take "additional measures," he said. He declined to name any country, but said they included both industrial and developing nations.
"There has been a clear message from some parties, and that would certainly be very good news," he told reporters.
The pledges in the Copenhagen Accord are purely voluntary, and are insufficient to meet the goal scientists have set to limit the average global temperature to 2 degrees Celsius (3.8 Fahrenheit) above what it was before the industrial age began.
Gomez Robledo said the side issues of funding, technology and forestry "are almost ripe," and negotiators will work on disputed details over the next five days.
The conference president, Mexican Foreign Secretary Patricia Espinosa, told the delegations Sunday she had assigned teams of two ministers, one each from a wealthy and developing country, to focus on specific issues and give political guidance to the negotiators.
The most troublesome issue - and one that could still undermine even the limited ambition envisioned for Cancun - was whether industrial countries would agree to further emissions cuts as spelled out in the 1997 Kyoto Protocol.
Under Kyoto, 37 nations and the European Union agreed to cut greenhouse gases by a total of 5.2 percent below 1990 levels by 2012. Those countries are on target to meet their obligations, but some of them have balked about accepting more mandatory cuts after 2012.
Japan caused an uproar last week when it flatly said it will refuse to go along, as long as all major emitting countries do not have similar obligations. The United States was assigned a reduction target, but it rejected the treaty. Developing countries, including China and India, were excluded from Kyoto's strictures.
Explore further: Measuring phosphorus loss from Midwest crop fields