The Earth feels the impact of human activities.

Though nature can`t communicate with us directly, we do receive feedback: Everything from pollution to global warming is evidence of the harmful consequences of our actions.

Thankfully, the University of Colorado at Boulder -- nationally renowned for its green practices -- has a number of staff members dedicated to teaching members of the community how they can reduce their damage to the environment.

Green CU

For more information on sustainability efforts at CU, visit the campus` Environmental Center online at ecenter.colorado.edu .

Here are five simple things students can do to offset their impact.

1 Replace bulbs

You can switch out

incandescent light

bulbs with newer, energy-efficient compact fluorescent lights (CFLs), a "really promising technology" that is "70 percent more efficient" than traditional bulbs and "can last up to 10 years," said Scot Wooley, program manager for Student and Community Outreach for Renter Efficiency.

SCORE is a student-run and operated program that offers "peer-to-peer education for students on how they can save money and carbon at rental properties," Wooley said.

"One of the easiest things we can do is to promote environmental consciousness through little, simple acts," he said.

Not only can CFLs light your home for longer and for less money, the bulbs are also recyclabl.

Many hardware stores that sell CFLs, from national chains such as Home Depot to local shops including McGuckin Hardware also have bins where customers can drop off broken and/or worn out bulbs, Wooley said. Proper disposal means a lower impact on the environment as well.

The only potential downside to CFLs is the "small amount of mercury" contained inside the bulb, Wooley said. However, the threat posed by the mercury is almost negligible.

"The amount of mercury in a CFL is the same amount you`d find in a can of tuna at the grocery store," he said. "If you`ve eaten tuna, ever, you`ve consumed more mercury directly than you ever would with the light bulb."

2 Unplug

Keeping appliances

plugged in when they

aren`t in use draws a large amount of wasted power from the grid, and also increases your energy bill.

Everything from a cell phone charger to a TV uses electricity when it`s off. These "energy vampires" create an unnecessary drain -- drawing a "phantom load" from the wall socket -- on the power supply and your bank account, Wooley said.

"We promote the use of power strips" to combat "phantom loads," he said. "You can turn them off and on (as necessary), rather than unplugging each appliance from the wall when you`re not using it."

One of the biggest "energy vampires" members on college campuses are computers, Wooley said.

"A lot of people think screensavers save energy; they don`t," he said. "We (encourage) students and the computer labs on campus to use the 'sleep` function on the computer. It`s a really easy (energy-saving solution) people don`t think about."

3 Cold laundry

Using cold water to

do laundry saves a lot

of energy.

"It`s been misrepresented that some detergents need hot water to work," Wooley said. "But most are cold water-(compatible) for colors and whites."

By "not making your water heater heat 50 gallons of water" to launder clothes, you`ll save money and reduce your impact on the environment, Wooley said.

"If 30,000 kids stop using warm water (to wash clothes)," he said, "there will be huge greenhouse gas reductions."

Hang-drying clothes, rather than using a dryer, is another environmentally friendly option when doing laundry, as it saves the energy and money spent using the appliance.

"You can hang them on a line, hang them over chairs," Wooley said. "Collectively, all our small actions can lead to big changes."

4 Smart transit

Resources at CU,

combined with

Boulder`s bike- and pedestrian-friendly roads, make car-less travel very possible.

CU`s Bike Station allows students to "rent out a Buff Bike for two days for free with a student ID," said Dan Baril, CU`s recycling program manager. Staff at the Bike Station will also assist bike owners with any repairs and maintenance their own bicycles might require.

The student Buff OneCard doubles as another Earth-friendly transportation option. Students receive a bus pass with their ID card, allowing them free use of Boulder`s bus lines. The bus pass "gets students around town, to Denver, to the airport" and to many other destinations, Baril said.

"You don`t really need a car when you combine the bus and bike options," he said.

5 Recycle

Probably the most

common first step

people concerned about the planet take is separating their trash from things that can be reused.

However, there are degrees of recycling: You can recycle the "traditional" products -- "aluminum cans, plastic bottles, paper products" -- or you can go "above and beyond" and recycle "plastic bags, Styrofoam and batteries," said Baril.

CU has a standard recycling program year-round, with "containers-grade and fibers-grade marked containers" in every building on-campus, Baril said. Recycling bins also occupy populated areas, with the university hoping to match every trash can on campus with a recycling bin by fall 2010.

"We always ask students to hold on for the extra 10-to-20 feet to throw their can, bottle or piece of paper into a recycling bin," he said. "It all adds up, for better or for worse."