United Nations Secretary-General Ban Ki-moon gives a speech during the opening of the High Level Segment of the U.N. Climate Change Conference COP 20 in Lima.

U.N. talks on a new global warming pact spilled into the weekend as negotiators quarreled over what kind of information to include when countries unveil their contributions before a key summit in Paris next year.

The yearly climate meetings rarely close on time and the two-week session in Lima was no exception as disputes that arose in the opening days remained unresolved by Friday’s scheduled close of the conference.

“There are still some points in the agenda that need more discussion,” Chinese delegate Zhang Jiutian said.

One of the most problematic issues was getting the more than 190 countries participating to agree on what information should go into the pledges that governments are supposed to put on the table for the planned Paris agreement.

Rich countries insisted the pledges should focus on efforts to control emissions of carbon dioxide and other heat-trapping greenhouse gases and were resisting demands that they include promises of financing to help poor countries absorb the effects of climate change.

Meanwhile, top carbon polluter China and other major developing countries opposed plans for a review process that would allow the pledges to be compared against one another before Paris. Their reluctance angered some delegates from countries on the front lines of climate change.

“We are shocked that some of our colleagues would want to avoid a process to hold their proposed targets up to the light,” said Tony de Brum, the foreign minister of the Marshall Islands, a Pacific nation of low-lying atolls at risk of being flooded by rising seas.

Though negotiating tactics always play a role, virtually all disputes in the U.N. talks reflect the wider issue of how to divide the burden of fixing the planetary warming that scientists say results from human activity, primarily the burning of oil, coal and natural gas.

Historically, Western nations are the biggest emitters. Currently, most CO2 emissions are coming from developing countries as they grow their economies and lift millions of people out of poverty.

“We are at a moment in the negotiations where countries need to show political leadership, to rise above narrow self-interest and make progress towards decisions that are for the larger, global good,” said the Climate Action Network, an advocacy group.

During a brief stop in Lima on Thursday, U.S. Secretary of State John Kerry said fixing the problem was “everyone’s responsibility, because it’s the net amount of carbon that matters, not each country’s share.”

According to the U.N.’s scientific panel on climate change, the world can pump out no more than about 1 trillion tons of carbon to have a likely chance of avoiding dangerous levels of warming. It has already spent more than half of that carbon budget as emissions continue to rise, driven by growth in China and other emerging economies.

Scientific reports say climate impacts are already happening and include rising sea levels, intensifying heat waves and shifts in weather patterns causing floods in some areas and droughts in others.

The U.N. weather agency last week said 2014 could become the hottest year on record.

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