BEIJING, June 13 (Xinhua) -- The United States and China have no choice but to cooperate closely on combating global warming to work out long-term solutions that could be shared by the world, said a visiting U.S. senior environmental official here on Friday.

    "We share a lot in common in terms of challenges ... our two countries have no choice but to cooperate more aggressively on clean energy technologies, because we face the same challenges and we need similar solutions," said James Connaughton, chairman of the White House Council on Environmental Quality.

    "Seventy percent of power generation in China is still based on coal, and in the United States it is fifty percent ... We have to work together on technologies for alternative fuels, biofuel and nuclear energy," he said.

    Connaughton is on a China tour talking with officials on climate change issues ahead of a U.S.-sponsored conference on energy and climate change that is to open in Seoul on June 22.

    It will be attended by representatives from the world's major economies like the United States, the European Union, France, Germany, India, Britain and China.

    Describing the tone of the Chinese side as "very constructive," Connaughton said China has set very aggressive goals especially in energy efficiency and has made significant strides like shutting down old power plants and inefficient industrial plants.

    Connaughton also hailed the Chinese government's efforts to reduce carbon emission and increase energy efficiency.

    "There has been very significant and positive direction in China in recognizing the urgency of fighting against climate change and designing strategies that will help meaningful progress in China," said Connaughton, adding that the U.S. government "welcomed that."

    As the only developed nation outside the Kyoto Protocol, the United States initiated climate change talks involving major economies in May 2007, when the United States was under growing pressure to contribute more to solving the problem of greenhouse-gas emissions.

    In their previous meeting in Paris in April, the major economies made progress in defining the building blocks of a new UN deal to fight climate change but with splits about whether to set a goal of halving greenhouse gas emissions by 2050.