The world needs to do more to combat desertification, which threatens close to a third of the planet\'s population, Algeria said Thursday at the opening of a conference here.\"One of the leading causes of global food insecurity -- namely the loss of natural resources, land degradation and desertification -- is poorly tackled,\" Algerian Agriculture Minister Rachid Benaissa said.He was speaking at the opening of conference in the Algerian capital bringing together around 100 experts from some 40 African countries. According to the United Nations, at least 43 percent of arable land in Africa is threatened by desertification which implies that 70 percent of the continent\'s economic activity is under threat.Desertification and ensuing famine, food insecurity and migrations also threaten 40 percent of the African population, or 400 million people. Thursday\'s Algiers meeting comes before the 10th session of the decision-making body of the UN Convention to Combat Desertification which opens in South Korea next month. \"Africa is the most affected and most vulnerable continent... but it is also the region where victory against this plague will be the most striking,\" the UNCCD\'s executive secretary Luc Gnacadja said. The conference\'s participants are to adopt a common roadmap to stop encroaching deserts.