Dear EarthTalk: With all the talk of the need for safe, renewable energy sources, isn't the elephant in the room really that we should use far less energy than we do? Wouldn't more rules about conservation (like not leaving commercial building lights on all night) make the challenges easier? -- Jennifer B., New York, N.Y.

In short, yes: Scaling back our energy consumption significantly, whether voluntarily or as a result of laws and regulations, would go a long way toward achieving our pollution reduction and air and water quality goals. But Americans -- and to a lesser extent those in many other developed nations -- have never been very good at using less of anything, let alone the energy that makes everything in our whiz-bang modern world possible. That said, conservation is going to play an increasingly important role in all of our lives as we struggle to reduce our collective carbon footprints in a quickly warming world.

President Obama has repeatedly highlighted the need for greater conservation efforts when it comes to shoring up our existing and future energy reserves and reducing our dependence on foreign sources of oil. The American Recovery and Reinvestment Act of 2009 set aside upwards of $3 billion to bolster efforts across the country to weatherize existing buildings in order to conserve energy.

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Grants to local communities for such projects, along with calls for voluntary reductions in energy consumption, are part of the plan. The White House is also betting on technology by subsidizing various initiatives aimed at reducing energy use and making our existing power network more efficient overall. Research has shown that investments in energy efficiency that promote conservation are cheaper and provide quicker returns than building new and cleaner power plants. A recent study released by Lawrence Berkeley National Laboratory predicts annual spending on energy efficiency and conservation to quadruple to as much as $12 billion a year by 2020.

As for what you can do to promote conservation, lead by example -- and you'll see your energy bills go down, too. Turn lights, computers and TVs off when you are done using them. If you're remodeling or building a new home, occupancy sensors that turn lights on and off as people enter or leave rooms is a good investment, as is making use of natural light in more overt ways to obviate the need for artificial lighting in daylight hours. Also, purchasing appliances rated for good energy efficiency under the federal government's Energy Star program will save energy. Likewise, driving a hybrid or electric vehicle, or foregoing a car altogether in favor of public transit, biking or walking, is a great way to conserve energy.

One way that awareness about the importance of energy conservation is being promoted around the world is through "Earth Hour," which began in 2007 when 2 million individuals and 2,000 businesses in Sydney, Australia, turned their lights off for one hour to make a statement about the need to fight climate change. Within a year, the concept had spread to more than 50 million participants in 35 countries. In 2011 Earth Hour drew participants in 135 countries; organizers expect the 2012 event (March 31 at 8:30 p.m., wherever you live) to be even bigger. Similar but unique "Lights Out" movements in San Francisco and other American cities will align with Earth Hour as well.

Contacts: Energy Star, www.energystar.gov; Earth Hour, www.earthhour.org; Lawrence Berkeley National Laboratory, www.lbl.gov; Lights Out San Francisco, www.lightsoutsf.org.

Dear EarthTalk: I heard someone say that legalizing pot -- as Californians considered doing last year -- would benefit the environment. How would that be? -- William T., Portland, Ore.

It is well known that legalizing pot could have great economic benefits in California and elsewhere by allowing the government to tax it (like it does on liquor and cigarettes), by ending expensive and ongoing operations to eradicate it, and by keeping millions of otherwise innocent and non-violent marijuana offenders out of already overburdened federal and state prisons. But what you might not know is that legalizing pot could also pay environmental dividends as well.

Nikki Gloudeman, a senior fellow at Mother Jones magazine, reports on the change.org website that the current system of growing pot -- surreptitious growers illegally colonizing remote forest lands and moving pesticides, waste and irrigation tubes into otherwise pristine ecosystems -- is nothing short of a toxic scourge. Legalizing pot, she says, would clean things up substantially, as the growing would both eliminate the strain on public lands and meet higher standards for the use and disposal of toxic substances.

Legalization would also reduce the environmental impacts of smuggling across the U.S./Mexico border, says Gloudeman: "Cartels routinely use generators, diesel storage tanks and animal poison to preserve their cache, when the border area is surrounded by more than 4 million acres of sensitive federal wilderness."

Also, legalizing pot would move its production out into the open, meaning that growers would no longer need to rack up huge energy costs to keep their illegal indoor growing operations lit up by artificial light. This means that the energy consumption and carbon footprint of marijuana growers would go way down, as the light the plants need for photosynthesis could be provided more naturally by the sun.

Yet another green benefit of legalizing marijuana would be an end to the destructive eradication efforts employed by law enforcement at bust sites, where the crop and the land they are rooted in are sometimes subjected to harsh chemical herbicides for expedited removal. The legalization of pot in the U.S. would also likely open the door to the legal production of hemp, a variety of the same Cannabis plant that contains much lower amounts of the psychoactive drug, THC. Proponents say hemp could meet an increasingly larger percentage of our domestic fiber and fuel needs.

Cannabis, the plant from which marijuana and hemp is derived, grows quickly without the need for excessive amounts of fertilizer or pesticide (it's a "weed" after all) and absorbs carbon dioxide like any plant engaged in photosynthesis.

The fiber and fuel derived from hemp would be carbon neutral and as such wouldn't contribute to global warming -- and in fact could help mitigate rising temperatures by replacing chemical-intensive crops like cotton and imported fossil fuels like oil and gas.

Of course, one might argue that the best thing for the environment would be to stop growing cannabis altogether. "But let's be real: That's never going to happen," Gloudeman said. "In light of that, the next best bet is to make it legal."

Contacts: Change.org, www.change.org; Drug Policy Alliance, www.drugpolicy.org.

EarthTalk is written and edited by Roddy Scheer and Doug Moss and is a registered trademark of E -- The Environmental Magazine (www.emagazine.com). Send questions to: earthtalk@emagazine.com