With its vast tracts of desert, the Arab world will be one of the regions hardest hit by climate change. What is not known is how climate variability and change will impact this large area. And even less is known in the way of practical guidance and how to adapt to what happens. To address this serious knowledge gap, the World Bank and the League of Arab States have launched a joint program to produce the first body of knowledge addressing climate change adaptation for all 22 Arab countries. The report will be prepared with local partners, including researchers and experts on climate change and related issues.