Nairobi, May 1 -- Whether you're watching television or reading a newspaper, the outlook for our planet appears increasingly grim. Just within the past week, torrential rains have wreaked havoc from East Africa to the Middle East and across vast expanses of Asia.

Meanwhile, unprecedented tornadoes are tearing through North America. Clearly, something has gone terribly awry with our climate, and we're ill-prepared to face it. Nature is sending us a clear message: it's time to adopt new strategies to address climate change.

At the forefront of this global challenge are urban centres. According to the Intergovernmental Panel on Climate Change (IPCC), cities are responsible for over 70 percent of greenhouse gas emissions and are also most s...