Attempts at such green communities have had mixed results. Arcosanti , the ecotopian town in the Arizona desert, was started three decades ago. Still a work in progress, it is now being encroached on by Phoenix’s suburban expansion.

China, with help from American partners, has embarked on building instant rural communities and cities designed to limit environmental impacts, but recent reports have disclosed many problems.

Still, environmental campaigners appear enthusiastic about Masdar City, which is part of a planned $15 billion investment in new energy technologies by Abu Dhabi.

At an international energy conference in that city last month, Jean-Paul Jeanrenaud, director of the One Planet Living initiative of the environmental group WWF International (known in North America as the World Wildlife Fund), said independent monitoring would help ensure that the project lived up to its billing.