For the first time in the history of civilization, more than half of the world's population lives in cities. Here in America, this trend has been underway for more than two centuries -- as people have moved closer to cities in search of the opportunities and amenities -- from housing, to transportation, to jobs -- that metropolitan living offers.
The pace of American urbanization is only expected to increase over the next several decades, as our population is expected to grow by another 50 percent -- another 120 million people requiring another 200 billion square feet of homes, office buildings and other construction.
As fast as that seems, it doesn't compare to the seismic demographic shift we're seeing across the globe. A century ago only one in ten people lived in cities -- the rest lived in small villages and on farms. But by 2050 it is predicted that two-thirds of the world's population will call urban and metropolitan areas home. Especially in the so-called "megacities" of sub-Saharan Africa, Southeast Asia and Latin America, what the U.S. experienced over a period of centuries is occurring in a matter of years.
As a result, millions of people are increasingly vulnerable to the deprivations associated with overburdened infrastructure, inadequate housing, and outmoded health systems. In fact, UN-HABITAT projects that within three decades, one of three people will live in near total despair -- lacking sanitation and clean water, exposed to the imminent effects of climate change, fueling the spread of disease and possible pandemics.
But with good governance, sustainable planning and development practices in these metropolitan areas, we can bolster these families', both at home and abroad, access to unprecedented opportunities for economic and social progress.
That's why this week, leaders from around the world will meet in Brazil at the World Urban Forum -- a unique venue to listen and share best practices and find opportunities for partnership that will lift the standard of living for billions of people, promote democracy and human rights, and enhance global health, food security, energy efficiency, clean construction and green jobs.
To be sure, the United States is already pursuing a robust domestic sustainable development agenda that bolsters America's metro areas. Under President Obama's leadership, we are tying the quality and location of housing to broader opportunities like access to good jobs, quality schools, and safe streets. Across the Federal government, we're working together to create green jobs and products, build affordable, energy efficient homes and promote more sustainable development patterns -- all so we can meet the needs of the present and ensure the futures of our children and grandchildren.
But the Obama administration also understands that the United States has a stake in ensuring that countries across the globe usher in a new era of sustainable economic growth and development -- opening new markets for green technology and American products, reversing the effects of global warming, and perhaps most importantly, ensuring that billions of families live in communities of choice, opportunity, and hope.
If we fail to live up to this responsibility, the impact is clear for America's economy and security alike.
I believe we can, but we can't do it alone. That's why the U.S. is not only leading by example--creating strong, sustainable communities at home -- but we're also engaging partners around the world and supporting their efforts.
Indeed, the U.S. delegation to the World Urban Forum, which I'm honored to lead with our colleagues from the Department of State, the United States Agency for International Development and the White House, relishes this chance to listen, learn, and share our own lessons from the "laboratories for change" that are our metropolitan areas.
Together, we can seize the historic opportunity before us to shape the forces of urbanization, creating a healthier, more inclusive future for our cities and metropolitan regions, and charting a more sustainable global future for generations to come.