When I spoke at the Global Urban Development Forum in Beijing last week, I presented the great opportunity that I believe China now enjoys: to become a world leader in green urban development to the benefit of Chinese people as well as people in the rest of the world.

China is currently in the middle of a massive development transformation. Having lifted about 500 million people out of poverty during the last three decades, the country is determined to meet the needs of its remaining poor and to improve the quality of life in general for all its citizens. This is being done in the context of important social and economic change.

For example, massive rural-urban migration is rapidly changing the face both of rural and urban life, as well as the structure of the economy. These and other development challenges are daunting enough in their own right given the country's massive scale, but they are compounded by the additional challenge of climate change.

China is effectively faced with the imperative of completing its modernization drive through an entirely different development path from that taken by the developed world - a low-carbon, climate-resilient path. Unlike in the past, there are no readymade solutions or models to follow. Low-carbon development has never been attempted before. There are no road maps. China is forging new ground, and because of its size all eyes focus on it.

On several dimensions of climate change, China has already emerged as a leader. For example, the country has mainstreamed climate change into its overall development agenda. Its most recent reflection can be seen in the 12th Five-Year Plan (2011-2015). China has set rigorous energy efficiency targets for itself, too. In the run-up to the 2009 climate change conference in Copenhagen, Denmark, China announced that it would reduce its emission intensity by 40-45 percent over 2005 levels by 2020. Recent reports suggest that China's energy intensity fell by 14.4 percent between 2005 and 2009.

China has also made significant investments in renewable energy: it invested more than $15 billion in 2008. It is the world's second largest wind power market, the biggest photovoltaic manufacturer, and it is emerging as a leader in electric cars, solar power and wind power. In each of these areas United Nations Development Programme (UNDP) has worked closely with China over the years.

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.