UNITED NATIONS (CNN) -- Chinese President Hu Jintao told a U.N. summit on climate change Tuesday that China will reduce greenhouse gas emissions and increase reliance on clean energy sources in coming years.
In what was called the first speech on climate change by a Chinese leader at the United Nations, Hu outlined some specific steps but provided no firm target for reducing greenhouse gas emissions that cause global warming.
As one of the world's two largest greenhouse gas emitters, China is a major player in international negotiations on a new global climate change treaty.
Hu reiterated past calls by China for industrialized powers such as the United States, the other largest emitter, to contribute more to a solution because they pollute more in developing their economies.
In his speech, Hu said China will "endeavor" to cut emissions of carbon dioxide -- the most prevalent of the greenhouse gases that cause climate change -- by "a notable margin" in coming years.
He also said China will "vigorously develop renewable energy and nuclear energy" with the goal of increasing the share of nonfossil fuels in total energy consumption to 15 percent by 2020.
In his most specific proposal, Hu said China will increase forest cover by 40 million hectares by 2020 as a way to offset greenhouse gas emissions by industrial polluters, cars, airplanes and other sources. The increase, equal to more than 150,000 square miles, or an area almost as big as California, would be based on China's forest cover in 2005, according to Hu.
Forests serve as carbon "sinks" by absorbing carbon dioxide from the atmosphere and storing it.