The rising number of natural disasters brought on by climate change is seriously threatening developing countries, and more “superdisasters” are in the works as the world’s poor concentrate in ever more vulnerable places, according to a report released yesterday by the Red Cross. In the past six years, the number of people who needed aid after disasters such as floods and hurricanes rose from fewer than 500,000 a year to some 5.5 million a year, more than the number needing aid from armed conflicts. Last year, the warmest year on record, more than 25 million people were driven from their homes by drought, floods, deforestation, and declining soil fertility, the report found.