Days after the United States announced to cut its carbon dioxide emissions by 17 percent from 2005 levels by 2020, China promised to slice carbon intensity in 2020 by 40 to 45 percent compared with 2005 levels.
The respective policy movements of both China and the US, the biggest two emitters in the world, won global attention, if not instant applause.
The early signs of the concerted efforts could be sensed after the two countries, the biggest developed and developing economies, released a joint statement on Nov 17 during US President Barack Obama's first China visit.
The two sides, according to the joint statement, had a "constructive and fruitful dialogue" on the issue of climate change.
It also said that the two sides were determined, in accordance with their respective national conditions, to take important mitigation actions.
The policy announcements from the two countries came just as the international community was worried about a possible stalemate at the United Nations Climate Change Conference in December in Copenhagen, Denmark.
Although not required by the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol for quantitative greenhouse gases (GHGs) emissions cut, China, defined by the United Nations as a developing country, still puts a drastic slash of its GHGs emissions in the coming ten years, even at cost of lowering its own economic development speed.
Economists estimated that China might double its current gross domestic product (GDP) by 2020. A 45-percent reduction of carbon emissions per unit of GDP means China would emit slightly more carbon dioxide than current levels.
At the same time, the Chinese government voluntarily set "the binding goal," which is to be incorporated into China's mid- and long-term national social and economic development plans.
It's much more than what a developing nation is expected to offer, out of responsibility and sincerity to addressing the common challenge faced by the international community.
Held by the UNFCCC accountable for contributing most of the total global carbon dioxide emissions, which were assumed to warm the planet and consequently result in natural disasters, many industrialized countries dodged their responsibilities of cutting emissions to levels that meet requirements of the Kyoto Protocol and the Bali Roadmap.
The United States, in spite of announcing a meaningful emissions cut of 17 percent, still lags far behind what the UNFCCC requires developed countries to behave.
In the Sino-US joint statement, the two sides were committed to reach a legal agreement at the Copenhagen conference, which includes emissions reduction targets of developed countries and appropriate mitigation actions of developing countries on the basis of the principle of common but differentiated responsibilities and respective capabilities.
The US and China also agreed substantial financial assistance to developing countries on technology development, promotion and transfer, which was largely invalid in the past years.
As China takes the lead to exemplify how a developing country, with the world's biggest population, could do to a better future of the world, it is now the developed world's turn to show their sincere care for a greener Earth.