A lightbulb may not be the first thing that springs to mind when thinking about revolutionary technology. Yet science and smart policy have the potential in today's world to transform an ordinary household object into a revolutionary innovation.
Recently, I visited an ambitious project to promote energy-saving lighting in China. By phasing out old-fashioned incandescent lightbulbs and introducing a new generation of lighting, China expects to cut national energy consumption by 8 per cent.
This can have a profound global impact. Consider this: lighting accounts for 19 per cent of world energy consumption. Scientists say we can reduce that by a third or more merely by changing lightbulbs.
A breakthrough like this highlights one of the many ways in which ordinary people and businesses can reduce energy use and cut greenhouse gases. It underscores the essential role that governments can - and must - play in promoting the green economy. And it highlights the special responsibility of the government of China to lead in the global fight against climate change.
China is one of the world's fast-growing economies. Last year it also became the leading emitter of greenhouse gases. It is clearly important for the world that China pursues sustainable economic and energy policies - those that reduce both emissions and poverty.
The key is giving a priority to clean energy, which can create new jobs, spur innovation, and usher in a new era of global prosperity.
Those who embark on this path early will reap rewards. They will be winners in the global marketplace. And assuming that prosperity is shared equitably, they will also strengthen stability at home.
There can be no argument that China today is a global power. And with global power comes global responsibilities. Without China, there can be no success this year on a new global climate framework. But with China, there is an enormous potential for the world to seal a deal in Copenhagen.
On September 22, I will convene a summit of world leaders to look at the challenges - and the opportunities - we face in the run-up to Copenhagen.
At the G-8 summit in Italy this summer, it was agreed to reduce carbon emissions by 80 per cent by 2050. I applauded this. But I also said that was not enough. To be credible, we need to match ambitious long-term goals with ambitious mid-term targets, with clear baselines. I will repeat this call in September.
I will also emphasise that major developing economies have a critical role in the negotiations: Brazil, India, Mexico, South Africa and, perhaps most important of all, China.
Already China has devoted a sizable portion of its national stimulus spending to renewable energy and green economic growth. It has become a world leader in wind and solar technology. China's dynamic renewable energy sector is worth nearly $17 billion and employs close to one million workers.
This is impressive, but it is just a beginning. China, for example, has enough wind resources to generate more electricity than it currently uses.
Imagine the potential. Imagine if, thanks to wind and solar, China could wean itself from coal, which accounts for 85 per cent of its carbon emissions. And if China were to do it, so could much of the rest of the world. In so doing, China can serve as a model not only for developing nations, but for the whole world.
We must also adapt to those climate impacts that are already wreaking havoc on communities, particularly in the least developed countries. Adaptation programmes help strengthen climate resilience. Going forward, they should be part of how we do development differently. Mitigation and adaptation are equal partners: one without the other makes no sense. They must be priorities for every government.
If we have learned anything from the crises of the past year, it is that our fates are interrelated. As Chinese Premier Wen Jiabao said earlier this year, "Issues such as climate change bear on the very survival of mankind. No country can be insulated from these challenges or meet them on its own. The international community should intensify cooperation and respond together."
As we move towards Copenhagen, I urge China to exercise still further the global responsibilities that come with global power. I ask China to act in the global public interest, as well as its national interest. For at the end of the day, as Premier Wen aptly put it, they are one and the same.
By changing a lightbulb, and changing our mindset, we can change the world.