It’s in the news constantly, and it’s no secret the Earth is heating up. Glaciers are melting. The sea level is rising.

Look at the shrinking of the Greenland ice cap and the Antarctic ice shell.

Look at the expansion of tropical diseases that are no longer limited to tropical places.

Look at how far polar bears have to go to find ice.

And the list continues.

It’s happening, but the reason for this global warming is a little bit more of a mystery.

The debate is not about whether it is happening, but rather why it is happening and how rapid and severe warming is occurring, said Garry Running, geography and anthropology professor and department chair.

“The Earth’s climate has been changing for 4.9 billion years,” he said. “It’s been warmer. It’s been colder. It’s been this. It’s been that. There’s no debate about that.”

But what the scientific community is debating is whether the evidence of global warming is pointing to humans as the cause, to some natural variation in climate or some combination of the two, he said.

According to the U.S. Environmental Protection Agency, global warming is defined as “an average increase in the temperature of the atmosphere near the Earth’s surface and in the troposphere, which can contribute to changes in global climate patterns.

“It can occur from a variety of causes, both natural and human-induced,” according to the agency, and it is often associated with increased emissions of greenhouse gases from human activities.

Running said there are more of these gases in the atmosphere than 100 years ago, so it’s not a surprise the temperatures are rising.

And policy makers are trying to figure out what to do about this, he said.

A major change in global weather and climate that would result in real problems for people could happen in the lifetimes of people alive today, which is what prompted talk of policy, he said.

“We’re not at the point where we can say with 100 percent certainty that we can predict exactly what’s going to happen,” Running said, but “we are in the position to say that there is a good chance that one of the things that could happen is really bad.”

The ramifications of this warming are extensive, he said, including the continuing rise of sea level.

If the models are correct, by 2050 sea level will be up another 30 centimeters, he said.

“A lot of coastal cities would be subject to more flooding. A lot of coastal plain agricultural areas would no longer be available, which means food supplies would be reduced, which means famine,” Running said, adding these are just some of the major consequences.

Freshman Ashley Zimmer said she thinks the recent “weird weather” has a lot to do with global warming, and it does concern her. She said she’s been hearing about it a lot in the media.

“I was watching the Academy Awards and Al Gore was talking about that,” she said, and “I know that a lot of celebrities are trying to get the word out by driving hybrid cars.”

She said she even saw a movie, “The Day After Tomorrow,” that dealt with the issue of the melting polar ice caps and a new ice age.

“(The movie) is really exaggerated. Obviously we’re not going to have an ice age tomorrow,” she said, “but . it’s going to affect our offspring.”

But if humans are causing it, Running said we can undo it by simply being smart about what we do to the environment, citing reducing the amount of gases we put in the atmosphere, driving less and more efficiently, insulating houses, turning off lights and buying locally.

He said before long people will realize some changes need to be made.

“I wouldn’t go into the Hummer sales business, because I don’t think it will be very long before the public will accept this idea to the point where they’re going to make some changes about their consumption of things, whether politicians and the government lead or not,” he said. “I think the average Joe on the street is going to see and hear enough to be convinced on their own that they are going to make personal changes.”

And Zimmer said she does her part.

She said the issue is always in the back of her mind and tries to recycle as much as she can.

Junior Alan Voss said he is educated on the issue as well.

“I know that no one is entirely sure what exactly is going on and it very well could be a natural phenomenon,” he said, adding he tries to help by turning off appliances and lights when he isn’t using them.

Overall Voss said global warming is a concern of his, but not a big one.

“It really doesn’t affect me right now,” he said.

So while the jury is still out on what is causing the warming and how extensive the effects will be, Running said one thing is for sure: “We’ll know when Florida is underwater.”