Addressing the social, environmental and economic challenges associated with rapid and growing urbanization is bringing some 3,000 experts from around the world together in London this week for the \"Planet Under Pressure 2012\" conference. With world population forecast to increase from 7 billion today to more than 9 billion by 2050, humanity\'s urban footprint will take up 1.5 million more square kilometers of land by 2030 at current rates, an area comparable to that of France, Germany and Spain combined. That translates into an average 1 million more city dwellers every week for the next 38 years, with the world\'s total urban population forecast to increase from 3.5 billion today to 6.3 billion by 2050, according to Planet Under Pressure 2012 conference organizers. These trends are impossible to stop, practically speaking, which means that rather than addressing the question as to whether or not urbanization should take place, but how best to urbanize, states Dr. Michael Fragkias of Arizona State University, one among nearly 3,000 conference participants. \"Today\'s ongoing pattern of urban sprawl puts humanity at severe risk due to environmental problems,\" Fragkias adds, issues that conference attendees intend to discuss, debate and offer solutions to. \"Dense cities designed for efficiency offer one of the most promising paths to sustainability, and urbanization specialists will share a wealth of knowledge available to drive solutions.\"