Louis are also considered high risk for severe tornadoes, according to Harold Brooks of the National Oceanic and Atmospheric Administration's Severe Storms Laboratory in Norman, Oklahoma.

CNN: Moore in bull's-eye twice, science may know why

The last time the worldwide carbon level was probably that high was about 2 million years ago, said Pieter Tans of the National Oceanic and Atmospheric Administration.

NPR: Greenhouse Gas Milestone; CO2 Levels Set Record

The Ocean in a High CO2 World symposia are co-hosted by UNESCO-IOC, The Scientific Committee on Oceanic Research (SCOR) and the International Geosphere-Biosphere Programme.

UNESCO: MEDIA SERVICES