At any given time, dozens of studies are underway to address specific issues in Earth & Life Studies that will lead to reports. These studies range in scope and length: some rapidly address questions to meet immediate decision making needs (for example, one report on why New Orleans' levees failed in Hurricane Katrina was absolutely necessary before the next hurricane season), while others deal with broader or ongoing issues and can span a number of years (as in the case of an ongoing review of efforts to restore the Everglades).