It's in the news, but many Americans remain unclear about what is happening to our climate, the "expected" weather, and its variability. The American public is still too unaware of the potential impacts of these changes on their lives and on future generations. Nonetheless, the available evidence strongly indicates that human activities are playing a significant role in bringing about climate change, especially in the last few decades of the 20th Century and the first eight years of the 21st Century.

Significant changes in climate as a result of these human activities are projected for the rest of the 21st Century and beyond. The scientific analyses also strongly indicate that the globally-averaged temperature increase is resulting from rising atmospheric levels of radiatively important (mostly heat-trapping) gases and particles, lending credence to concerns about much larger changes in climate being predicted for the coming decades.

Computer-based analyses of the complex physical, chemical, and biological processes affecting the climate system, backed by direct observations of these processes, have implicated human activities, especially the burning of fossil fuels along with land use changes, as major factors in the increasing concentrations of the heat-trapping gases and particles. Analyses of the climate system also indicate that, without major policy or technology changes, the climate will continue to grow warmer over most of our planet.

This presentation begins with a discussion of the current understanding of the concerns about climate change and the role being played by human activities, then examines several of the potential resulting impacts on humanity and our planet, and finishes with a discussion of our possible responses to this all too real issue.

Special ceremony.  Several student members of Sigma Xi are graduating this spring.  In a brief ceremony preceding the scheduled program, they will be honored with the presentation of a Sigma Xi cord, to be worn with their graduation gown on the day of commencement.  Each student will bring us up to date on their plans for the future.  We wish them the very best in their future research projects.