Australia's former prime minister urged China and the United States -- the top two emitters of carbon dioxide from fuel combustion -- to cooperate on climate change.

"If the United States were to achieve some sort of compact with the Chinese on how to entrench national actions within a global regulatory framework, then we'd start to cook with gas, literally," Kevin Rudd told The Australian newspaper.

China emitted 8 billion tons of carbon in 2011 and the United States about 5.26 billion tons, says the International Energy Agency.

"China has massive national self-interest in ensuring that climate change is effectively dealt with," Rudd said. "Otherwise, China's moment in the sun -- that is, the next decade or two of China's economic and political position in the world -- could be undermined."

An IEA report in May said that China's emissions rose by 720 million tons in 2011 as more coal-fired power plants came on line. But its carbon intensity -- the amount of CO2 emitted per unit of gross domestic product -- decreased 15 percent from 2005 to 2011.

Emissions in the United States also fell in 2011, by 1.7 percent, which IEA attributed to a mild winter and a continuing shift from coal to natural gas for power generation.

Rudd argues that China isn't recognized enough for its domestic policy decisions on climate change, including its stance on coal, nuclear and clean energy.

Just before the 2009 Copenhagen, Denmark, climate change summit, China pledged to decrease carbon intensity 40-45 percent less than 2005 levels by the end of this decade, while switching to non-fossil fuels for about 15 percent of its energy.

"Quite large steps are being taken, driven by administrative and regulatory decisions by the Chinese state," he said.

But the United States, Rudd said, was "not lifting its weight sufficiently" in the area of climate change and so one key strategic objective was to "bring the Americans into this."

All countries -- developed and developing -- have a responsibility to achieve the objective set forth in the 2009 Copenhagen Accord to limit temperature increases to less than 2 degrees Celsius above preindustrial levels, Rudd said.

Australia, one of the world's highest per-capita emitters of carbon, aims to reduce national emissions to 5 percent less than 2000 levels by 2020 and 80 percent less than 2000 levels by 2050.

A carbon tax went into effect in July in Australia, under Prime Minister Julia Gillard's administration. An earlier version of a carbon tax, introduced by Rudd, led to his downfall in June 2010.