December 2006 UN Under Secretary General says: some experts estimate that the number of people at risk of displacement due to severe desertification will exceed 50 million over the next ten years.

That is from Overcoming One of the Greatest Environmental Challenges of Our Times: Re-thinking Policies to Cope with Desertification. (this conference was held on Dec. 17-19, 2006)

It is also referred to as "A Policy Brief based on The Joint International Conference: “Desertification and the International Policy Imperative” Algiers, Algeria, 17-19 December, 2006."

Here is the link address:

http://news.bbc.co.uk/2/shared/bsp/hi/pdfs/28_06_07unreportdesert.pdf

The authors were listed as:

Zafar Adeel, Janos Bogardi, Christopher Braeuel, Pamela Chasek, Maryam Niamir-Fuller, Donald Gabriels, Caroline King, Friederike Knabe, Ahang Kowsar, Boshra Salem, Thomas Schaaf, Gemma Shepherd, and Richard Thomas

From the Foreword:

"We also have mounting evidence that desertification leads to strong adverse impacts on non-drylands. The most common and visible are dust storms, typically originating in the Sahara and Gobi deserts and affecting the entire Northern hemisphere. In addition to dust storms, desertification is directly linked to downstream flooding, impairment of global carbon sequestration capacity, and regional and global climate change. These impacts on the natural environment are also linked to societal impacts. For example, some experts estimate that the number of people at risk of displacement due to severe desertification will exceed 50 million over the next ten years. Indeed, such migration of people is a top-level political issue in many countries like Algeria, Morocco, the United States, France, Spain and Italy."

 "This brief report summarizes the wealth of experience and expertise present at the Joint International Conference “Desertification and the International Policy Imperative” (17-19 December 2006, Algiers, Algeria). "

The foreword was written by Prof. J.A. van Ginkel UN Under Secretary General, and UNU Rector. UNU means United Nations University.

He later says:

"UNU has a mission to bridge the divide between the research and policy-making communities in order to address pressing global challenges such as desertification. And this is indeed the challenge of today: How can we pull all strands of this human, social and economic development together in a way that we arrive at success for the people most threatened by desertification? We have at our disposal today immense human, technological, institutional and even financial resources to overcome this challenge. What we need is a coherent, cohesive and integrated policy approach."