LONDON — China’s greenhouse gas emissions will peak between 2030 and 2040, the country’s science and technology minister said Monday, as crunch talks on climate change were getting under way in Copenhagen.

Wan Gang said the precise timing of the level would depend on China’s economic growth, rate of urbanization, and level of scientific development.

“There are some uncertainties here, so it is difficult to say whether it will be in the beginning, the end, or the middle, but I can say for sure it will be within that range (of 2030-2040),” he told the Guardian.

China, the world’s largest carbon gas polluter, has promised to make gains in energy efficiency, but has yet to announce a peak date for emissions.

World leaders gather in Copenhagen from Monday for landmark U.N. talks on tackling global warming beyond 2012.

Its task is to craft a global pact that will dramatically reduce man-made carbon dioxide emissions — invisible gases that trap solar heat and warm the atmosphere, interfering with Earth’s delicate climate system.

Developing nations, including China, insist that developed nations should bear most of the cost of tackling climate change.

Wan said the priority at Copenhagen would be to establish a framework for transferring funds and money, rather than getting hung up on figures.

“If we can achieve this goal, that is good enough,” he said.

“Copenhagen is very important to all governments and politicians. It’s an important turning point, but it is also just the start of human efforts to tackle climate change. It is not the end.”

Beijing said last month that by 2020 it would curb emissions per unit of gross domestic product by between 40 and 45 percent compared to 2005 levels.

The pledge then was not to cut emissions but was essentially a vow of greater energy efficiency that would see China’s emissions continue to grow along with its economy.

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