this is the Economics Report in Special English.The World Economic Forum saysthe most likely risk facing the world over the next 10 yearsis the severe disparity in income between rich and poor.The estimate was made in a new reportcalled the World Economic Forum's Global Risks 2013.Many of the issues discussed in the report are familiar.Food availability and the spread of extremism and terrorismare noted every year.But new risks, especially technological and financial ones,are becoming more important than ever.The World Economic Forum is based in Geneva, Switzerland.The non-profit group says its risk reportis based on surveys of more than 1,000 experts from around the world.They include industry leaders and specialistsin government, academics and civil society.The experts considered the likelihoodthat risks could become serious problems in the future.They also studied the impact, or influence,that these risks would have if they became reality.The experts judged the likelihood that a riskwould become a problem over the next 10 years.Sharp income differences between rich and poorwere the risk considered most likely.This is the second time in two years that the disparity in wealthwas identified as the most likely problem.It was followed by what the report calls "chronic fiscal imbalances,"or the failure of governments to deal with heavy debt over time.The risk said to have the biggest possible impactwas a major failure in the world financial system,like the collapse of a top institution or currency.But experts rated a water supply crisis as secondon the list of high-impact risks.The report's organizers saythis issue has generally received little attention.How the experts change their opinions is also something to note.This year, the mismanagement of the aging populationmoved from the 18th to the fifth most likely threat.The failure to deal with the costs and social issuesinvolved with an aging populationis now considered a risk with greater possible impact.The experts also were asked about extreme possibilities.The report calls these "X Factors."They include the likelihood of climate change going out of control,and even the results of discovering alien life forms.The World Economic Forum is an international groupwhose members represent industry,charitable organizations and other partners.Its stated goal is to improve the state of the world.