Twenty years ago, Taher Ibrahim raced his friends across Alexandria's beaches, now rising seas have swept over his favorite childhood playground. Alexandria, with 4 million people, is Egypt's second-largest city, an industrial center and a port that handles four-fifths of national trade. It is also one of the Middle East's cities most at risk from rising sea levels due to global warming.

The Arab world will be one of the regions worst hit by climate change but still lacks any coordinated response to its potentially devastating effects, experts said at a conference this week.

With hotter, drier and less predictable climates, the amount of water running into the region's streams and rivers is set to fall 20 to 30 percent by 2050, worsening desertification and food insecurity, the