While global warming is still a heated topic, there is no debate that the earth is getting warmer and humans are causing the climate change, said Eric Barron, dean of the College of Earth and Mineral Sciences.

"No climate model suggests the changes won't be large," Barron said. "The debate is how much, how fast and what impacts [global warming will have]. Our crystal ball is very cloudy."

Barron spoke Thursday to about 50 people in the Sparks Building about the predicted effects of global warming, as the first lecturer of the Global Warming Speaker Series. The series was organized by Eco-Action, a student group that focuses on the environment.

Barron discussed several climate models put forth by the U.S. National Assessment of Climate Change (NACC), a conference he mediated in 1998 and 1999.

The NACC "was convened [by former Vice President Al Gore] to look into the threats of global warming and climate change, and delegated by some of the top scientists in many different fields of study," Eco-Action member Jason Hart (junior-religious studies and psychology) said.

"It is a detailed overview of the consequences of climate change and mechanisms for adaptation within the Unites States," said Hart, who introduced Barron at the lecture.

Some of the climate models Barron presented predicted earth surface temperatures, precipitation, summer sea changes and food supply up to 100 years from now, showing the various ways global warming will affect the planet according to scientists.

Barron said the surface temperature of earth is expected to rise 1.5 to 4.5 degrees Celsius by roughly the end of the century. Global warming occurs because of carbon dioxide, a greenhouse gas and a "selective absorber," he said.

"The structure [of carbon dioxide] is such that it absorbs a particular wavelength of energy emitted from the earth and radiates a portion of it back to the surface, thus promoting warming," Barron said.

Several students who attended the lecture said the facts were presented with an unbiased, scientific viewpoint.

"He didn't really let his politics shine through," Meghan Ochs (junior-public relations) said. "He just presented the scientific facts as best he could based on the theories. [His presentation] was more optimistic than what I was expecting."

Eco-Action member Suzanne Wittman (senior-art) said that when a lot of people are learning about an issue like global warming, they tend to get their information from someone with a radical viewpoint.

"By not taking a radical stance, [Barron] really made himself very credible and a good source," Wittman said.

While scientists have a scope of the long-term trends of global warming, there's no way for them to know what will happen five or 10 years down the road, Barron said.

He said the way people deal with the uncertainty is to decide whether or not they are vulnerable to the changes.

"The future generations won't know what our forests used to look like" years ago, Barron said. "They'll travel to Maryland to get a Georgia peach, and it won't be an issue to them."

Hart said it is important for students to understand the facts of global warming.

"We will be the first generation to see [its effects], so we need to know the steps to take in order to protect ourselves and the natural environment," he said.

Katherine Stoner, vice-president of Eco-Action, said the club initiated the speaker series to get the message of global warming to the forefront of discussion at Penn State.

"We want the people of our generation to realize what an important issue [global warming] is because we're the generation that is going to be dealing with it in the future," Stoner said. "It needs to be addressed from many different facets, from an economic standpoint to even a religious standpoint. It's not just an environmental issue."

Eco-Action president Maura Cowley said global warming is also turning out to be a civil rights issue because low-income communities in the United States and people in developing nations are disproportionately affected by it.

"They're seeing a lot of the effects of global warming without reaping the benefits of excessive energy," Cowley said. "They're not the ones causing the problem, but they have to deal with the consequences."

Jeff Meadows (junior-chemistry, computer science and math) said he doesn't believe it has been proven that global warming has only been caused by humans.

"We've only been accurately recording temperature for a very short time period relative to the age of the earth, so I don't think we can fairly attribute any long-term climate change solely to human activity and presence," said Meadows, who did not attend the lecture. "We barely understand the problems, so I don't think any legislative solution is possible right now."

Cowley said the speaker series will include one speaker each month throughout the semester. Lectures will be held on the last Thursday of each month, except for February.

"We're hoping to have that lecture on Feb. 17, because that's when the Kyoto Protocol goes into effect internationally," Cowley said. "Since the U.S. isn't in it, we thought it would be a good way to raise awareness."

Members of Eco-Action and the Green Destiny Council run a campaign called Kyoto Now!, which serves to persuade Penn State to lower its greenhouse gas emissions to Kyoto Protocol standards -- or 7 percent of the university's 1990 emissions levels.

Cowley said the university could be much more efficient with its energy usage by using florescent light bulbs, better insulation and double windowpanes, and by eventually switching to renewable energy sources like wind and solar power.