As we get ready to celebrate Earth Day next week, I can't help but think about how technology both helps and harms our environment.

On the positive side, tech is helping cut down on the use of some resources. Reading newspapers and documents on screens means chopping down fewer trees for paper. Using email cuts down on the environmental cost not just of paper and envelopes but all the fuel it takes to get a letter from place to place. The ability to telecommute or participate in an online conference reduces fuel consumption and carbon emissions.

And, of course, it is technology that's enabling electric cars and hybrids, and more efficient heating, lighting and cooling systems. Sensor technology enables us to have lights turn on only when needed and off a few seconds later.

This product image provided by Philips shows a state-of-the-art LED light bulb. The bulb is the most energy-efficient yet, lasts about 20 years and is
This product image provided by Philips shows a state-of-the-art LED light bulb. The bulb is the most energy-efficient yet, lasts about 20 years and is supposed to give off a pleasing, natural-looking light. (AP Photo/Philips)

We have a lot more electronic devices, but the good news is that they are getting increasingly efficient. Still, globally, our demand for electricity is growing at the rate of 2.4 percent a year. That doesn't sound like much, but it compounds over time, which means a doubling of consumption between 2000 and 2030. Much of that growth is in developing nations. The U.S. Energy Information Administration projects annual U.S. consumption growth at only 0.8 percent between now and 2040 which is a much slower rate than we've experienced over the past 50 years. And much of that slowdown in growth has to do with more efficient technology.

Incandescent bulbs are rapidly on their way to extinction, which is a good thing. CFL bulbs are about 75 percent more efficient and LED bulbs -- which are starting to come down in price but are still quite expensive -- are even more efficient, generate almost no heat and last a lot longer, which means having to manufacture, ship -- and screw in -- fewer of them over time. The U.S. Department of Energy estimates that widespread use of LED lighting could save the "equivalent annual electrical output of 44 large electric power plants," saving "more than $30 billion at today's electricity prices."

Other electronic devices, including audio systems and TVs, are also getting more energy-efficient, but collectively they still consume a lot of power. And just because something is more efficient than what it replaced, that doesn't mean we should leave it on all the time. I used to think there was no need to turn off my solid-state audio system until I measured its energy use with a Kill A Watt EZ energy meter and discovered it was using a whopping 47 watts. My DVD player was sucking up 26 watts in idle mode and my digital video recorder, which had to run all the time so it could record shows, used 30 watts.

A few years ago the Energy Department estimated that, in the average home, 40 percent of all electricity used to power home electronics is consumed while the products are turned off. Some of this standby power, sometimes called "vampire power," is sucked up by appliances such as TVs that sip energy so that they'll work with a remote control and turn on almost instantly. The number of "always on" devices will skyrocket over time as more and more are connected to networks and always in "listening mode" for remote commands.

Industry efforts, government regulations and voluntary programs like the International Energy Agency's "1-watt initiative" are helping to reduce standby power, but the rest of us can do our part by switching off devices that don't need to be on and unplugging all those power bricks (like the ones that power our phones) that use small amounts of power even when they're not in use. A simple trick is to connect them to a power strip that you can switch off when you're not charging anything.

We also need to pressure companies to be more energy-efficient. You might not be using much power when you access the Internet on your energy-efficient laptop or mobile phone, but worldwide, according to the New York Times, "digital warehouses use about 30 billion watts of electricity, roughly equivalent to the output of 30 nuclear power plants."

McKinsey & Co., according to the Times, found that on average these data centers "were using only 6 percent to 12 percent of the electricity powering their servers to perform computations. The rest was essentially used to keep servers idling and ready in case of a surge in activity that could slow or crash their operations."

Finally -- and I admit I'm often guilty of buying the latest versions of gadgets -- we need to think about slowing down the replacement cycle. Every time we replace our cellphone or tablet it means that another one has to be manufactured and shipped to us, and our old one needs eventually to be recycled. All of that takes resources.

As we crave those new devices that I and other tech journalists frequently laud, we need to think of the total cost of ownership -- not just for us personally, but for the world and the planet we live on.

Contact Larry Magid at larry@larrymagid.com. Listen for his technology chats on KCBS-AM (740) weekdays at 3:50 p.m.