Refugee workers in the Sahel region where thousands of Malian refugees are fleeing violence in their country said this week they are witnessing firsthand the knotted challenges of food security, climate change and conflict in Africa. According to the U.N. High Commission on Refugees, more than 300,000 people have fled Mali since fighting erupted in the north in January between a Tuareg rebel movement and Malian government forces. Go to story #1

Worldwide carbon emissions trading volume rose 17 percent last year to 10.3 billion metric tons of carbon dioxide equivalent, with permits in the E.U. Emissions Trading System accounting for more than three-quarters of the total, the World Bank said in a new report. Carbon trading grew 11 percent by value to a record $176 billion, with a record number of emissions products traded. Go to story #2