While these achievements are impressive, much remains to be done. Despite low per capita carbon dioxide (CO2) emission, China's total emission accounts for more than 20 percent of global emission levels, and the country's current stage of rapid development makes it exceedingly difficult to reduce emissions. But China is committed to reducing CO2 emission intensity by 40-45 percent from 2005 levels by 2020. China has assessed its strategic priorities and recognized that the battle against climate change will be won or lost in cities. Cities are not only big CO2 emitters, but also especially vulnerable to the impact of climate change.

The challenges of developing low-emission cities in China are similar to those in other countries, but the scale is so much vaster. China currently has more than 20 cities with over 5 million people. And urbanization is growing fast: from 27 percent in 1991 to more than 45 percent today, and to a predicted 67 percent by 2030. China's cities will add about 350 million people in the next 20 years, more than the entire population of the United States, and its total urban population will be about 1 billion. This rapid urbanization inevitably implies higher emissions, higher average income, greater consumption, and greater demand for services and infrastructure.

But herein lies China's opportunity: in many countries, the challenge of retrofitting existing cities to become sustainable will be stark, but one which will have to be faced. In China, about 350 million future city dwellers are still living in the countryside. Their homes, streets, workplaces, public transport in cities all are yet to be built. China can construct them in a climate and environmentally friendly manner, and can become a model for the world.

How can this be done in practice? Critically, urban development requires a long-term perspective. A key aspect is urban planning in which climate change considerations need to be integrated. But some immediate actions can be taken: promoting electric cars and motorcycles, replacing coal with electric stoves for heating, and designing and constructing energy-efficient buildings. Some of these solutions are already happening. For example, a ban on gasoline-propelled motorbikes in several urban areas of China boosted the sale of electric bicycles from a mere 40,000 in 1998 to 21 million in 2008.

Investing in climate-resilient and low-emission infrastructure cities also provides other benefits. For example, reducing traffic congestion and air pollution will greatly benefit everyone living in our cities. Green cities bring blue skies.

Lastly, sustainable cities can only become a reality if their residents adopt sustainable lifestyles. Thus, it is crucial for China to continue to educate its population on environmental awareness. One important area is in energy efficient household appliances. China now produces more consumer appliances than any other country and their energy consumption is growing at a rapid pace.

How China's cities develop in the decades to come is of great significance both within China and beyond. As the largest developing country in the world, China is in a unique position to inspire and promote sustainable, low-emission urban development not only at home, but also abroad. In recognition of this, the Chinese government and the UNDP recently signed a strategic partnership agreement to strengthen cooperation in sharing China's experience with other developing countries.

In conclusion, the challenge of combining economic growth with low-carbon and climate-resilient urban development can and must be turned into an opportunity. China is already pioneering many innovative solutions that need to be shared across the world. Low-carbon urban development is imperative for the survival and healthy development of our economies and societies. To this end, the UN, and the UNDP in particular, look forward to working further with China and other partner countries to help build a sustainable, low-carbon, and poverty free future for all.

The author is UN assistant secretary general and UNDP's regional director for Asia and the Pacific.