The public is invited to free lectures in the third annual Sustainable Earth, Energy and Environmental Systems (SEEES) Seminar Series, Mondays, 7:30 to 9 p.m. at 155 Olin Hall at Cornell. Talks will explore sustainability from a variety of perspectives -- from that of Hollywood filmmaker Randy Olson, who will discuss his new film "Sizzle" Sept. 19 -- to noted local author Sandra Steingraber, who will discuss "Ethical Issues Arising from Global Change" Nov. 7.

The series kicked off Aug. 29, with a presentation by Cornell Professor Chuck Greene on "Getting to 350," which refers to stabilizing atmospheric carbon dioxide (CO2) concentration at 350 parts per million (ppm), a target that scientists agree we need to achieve by the end of this century if we want to avoid catastrophic climate change.

"Because of the climate system's memory," said Greene, professor of earth and atmospheric sciences, "the time window is relatively narrow for society to find solutions that avoid dangerous and largely irreversible rises in temperature, sea level and the incidence of extreme weather events."

Greene presented scientific evidence for targeting 350 ppm and discussed how the world's best scientific thinkers are attempting to come up with workable solutions to the challenge of replacing fossil carbon-based energy with more sustainable alternatives, such as algal bioenergy. Greene emphasized that to reach the 350 goal, society will need to develop geo-engineering techniques that capture CO2 directly from the atmosphere.

For example, deriving power from algae, he said, would directly capture CO2 from the atmosphere but would require a billion-dollar investment to implement at a commercial scale. Yet it holds great promise for stabilizing the atmosphere's CO2 concentration at a level that will prevent dangerous climate change, he said.

Upcoming SEEES talks:

Sept. 12: Cornell Climate Action Plan: In Principal and in Practice -- Professor Tim Fahey, Lanny Joyce, Cornell's director of energy management;

Sept. 19: Communicating Science to the Public: "Sizzing Dodos" -- filmmaker Randy Olson;

Oct. 3: Understanding Our Fossil Fuel Addiction -- Professor Rick Allmendinger; Community Roundtable on Hydrofracking -- Professor Chuck Greene;

Oct. 17: Climate Change and the Spread of Infectious Diseases; Impacts of Elevated CO2 on the Ocean -- Laura Harrington, associate professor, Bruce Monger, senior research associate;

Nov. 7: Ethical Issues Arising From Global Change -- Sara Pritchard, assistant professor, Sandra Steingraber, ecologist and author; and

Nov. 21: Posters on solutions -- Presented by students in SEEES's First-Year Writing Seminar.

"Society can only be successful in getting to 350 by century's end if it supplements aggressive greenhouse gas emission reductions with CO2 removal from the atmosphere and subsequent sequestration," he said.

Greene and a team of other sustainability experts from Cornell will travel to Qatar in the Middle East in November to discuss a plan for building a prototype of the system he envisions.

"I used to avoid talking politics in my lectures," he said, "but the climate change discussion has become so highly politicized that I feel I have no choice. I would like to be able to approach the U.S. government and request a billion dollars to invest in building a model power plant designed to save the planet, but I don't think I would meet with much success these days."

After Greene, local artist Jay Hart presented images of planet Earth based on data collected by spacecraft over the past half century. The images, Hart said, graphically illustrate the potential effects of climate change, as ancient rivers and lakes dry up, sea level rises and whole populations of people are forced to relocate. Hart's artwork is primarily based on elevation data collected on the Space Shuttle Radar Topography Mission. He used examples of his art to illuminate the interconnectedness between natural environments and the patterns of human settlement on the Earth's surface.

The SEEES Speaker Series is co-sponsored by Cornell's Department of Earth and Atmospheric Sciences and by the Cornell Center for a Sustainable Future. For more information and links to previous presentations in this series, visit http://www.eas.cornell.edu/cals/eas/news-events/sees-seminar.cfm.