KOENIGSWINTER, Germany (AP) — Outgoing U.N. climate chief Yvo de Boer shot down expectations of a comprehensive climate treaty this year, saying Monday that a major U.N. conference in December would yield only a first answer on curbing greenhouse gases.

His comments came just five months after the Copenhagen climate conference failed to yield much progress despite efforts by world leaders, including President Barack Obama.

De Boer said the next major U.N. climate conference in Cancun, Mexico, in December will "not provide an answer that is good enough."

He was speaking to reporters at an international climate meeting in Koenigswinter, near Bonn, the former German capital.

"A good outcome of Cancun will be an operational architecture on climate change," he said. "And then we can decide on a treaty."

De Boer said he expects such an international climate treaty before the end of 2012, but even that will "not be the definitive answer to the climate change challenge."

Originally, the Copenhagen conference was intended to produce the international treaty that has been in the works since 2007. Instead, it showed a great rift between industrialized nations, new economic powers like China, and developing countries.

Germany and other countries have said they have not given up on a deal in Cancun. Germany and Mexico are hosting the meeting in Koenigswinter of more than 40 ministers and high representatives, which is aimed at getting the U.N.'s negotiating process back on track.

German Environment Minister Norbert Roettgen said Monday evening the first full day of negotiations had seen some positive signals.

"I think the general feeling was that international climate negotiations have again started moving ahead," he said.

Also, there is progress on some issues of the envisioned climate treaty such as the safeguarding of the Earth's forests, the exchange of technology between wealthy and poor nations and the use of market mechanisms such as emission trading schemes, he said.

Roettgen said that Germany wants to allocate about $350 million of the $1.2 billion it pledged at Copenhagen for the next three years for forest projects and the remaining amount for projects to curb greenhouse gas emissions and for programs ensuring the adaptation to the consequences of climate change.

De Boer said what the Cancun conference can produce are decisions on some such sticking points.

A "functioning architecture" would provide nations worldwide with tools to fight climate change and "increase the level of ambition," he said.

In Copenhagen, nations did agree that global temperatures must not rise above 2 degrees Celsius (3.6 degrees Fahrenheit) in comparison with preindustrial times. In order to achieve this, scientists say industrialized countries need to cut their emissions of heat-capturing gases such as carbon dioxide by 25-40 percent compared with 1990 by 2020, and developing countries must enter a low carbon path.

De Boer said industrial nations have started to act, but are not yet doing enough.

"I don't think we will get enough of an answer in Cancun to get us to the 25-40 range," he said.

Also, while nations in Copenhagen agreed on a fast-start $30 billion financial aid package, poorer nations need assurances that this package actually consists of new and additional funds, he said.

By 2020, the annual help needs to be shored up to $100 billion and richer nations need to say how they are going to do that, he said.

"There will be no action without a great deal of funding," he said.