Peter Lehner is executive director of the Natural Resources Defense Council (NRDC). This Op-Ed was adapted from a post that appeared onthe NRDC blog Switchboard. Lehner contributed this article to LiveScience's Expert Voices: Op-Ed & Insights.

Last year, Americans started implementing a lot of smart, efficient solutions to cut waste. And it was time — we waste an awful lot of resources in this country, including 40 percent of our food and more than half our energy. By continuing to push for efficiency, we will save billions of dollars, protect our valuable resources and create a more sustainable planet. Here are five major ways we cut waste and helped protect the environment in 2013.

1. Americans boosted energy efficiency

Just in time for Christmas, a coalition of pay-TV and electronics companies, working with NRDC and several energy efficiency groups, announced their commitment to improve the energy efficiency of set-top boxes — including DVRs and HD boxes — by 10 percent to 45 percent, depending on the model. This move will save as much energy as three power plants generate, and result in energy savings of about $1 billion a year for consumers.

Also this year, the U.S. Department of Energy (DOE) finally issued proposed rules for four, long-delayed, federal energy-efficiency standards — thanks to pressure from NRDC and other groups — including for the electric motors that run everything from elevators to conveyor belts and consume about half the electricity used by the U.S. industrial sector. Over the next 30 years, the motor standards alone will save enough electricity to power every home in the United States for a year, and save consumers about $23 billion. The DOE also issued final efficiency rules for distribution transformers and microwave ovens, as well as proposed standards for furnace fans.

This year's new model building energy code, which my NRDC colleagues helped strengthen, will make new homes and major renovations more than 30-percent more energy-efficient than the older 2006 standards. The code also gives builders flexibility to keep costs down, and provides homeowners with information about their home's energy efficiency. This is a major win that will help homeowners save hundreds of dollars in energy and water costs each year while cutting carbon pollution from homes.

Of course, the biggest efficiency booster of all could be President Barack Obama's climate action plan, which will rely on energy efficiency as a tool to cut carbon pollution from power plants, and is helping scale up efforts already underway to make homes, buildings, industrial processes, equipment, appliances and electronics more efficient. NRDC estimates that a plan to cut carbon pollution 30 percent by 2020 would net health and environmental benefits worth $30 billion.

2. Americans are tackling food waste

My colleague Dana Gunders helped make food waste a topic of national discussion this year. American food-waste habits, in addition to the wasting of food itself, use up four percent of U.S. oil and 25 percent of the nation's fresh water. On a global scale, people use about 28 percent of agricultural land to grow food that never gets eaten. I spoke at a TEDx event in New York about the vast scope of food waste in the United States, and the simple fixes that can help address it, starting with fixing America's confusing date labeling system. Most dates on food don't tell you whether it's safe to eat; confusing date labels lead up to 90 percent of Americans to throw away good food. The U.S. Department of Agriculture and the U.S. Environmental Protection Agency (EPA) launched the first national attempt to address food waste this year, issuing a challenge to the food industry to find ways to reduce food waste. Companies like ConAgra, General Mills and Unilever have already signed on, as well as several universities, sports teams and entertainment venues.

3. Americans are ramping up recycling and composting

Waste, in its most literal sense, is garbage. Americans throw out about 4.4 pounds of stuff, per person, per day — and one of the single biggest sources of that waste is food. New York City launched a successful, pilot, curbside food-waste collection program this year, and plans to require residents to separate food scraps for composting starting in 2016. The city could save $100 million each year by diverting organic waste from landfills and turning it into healthy soil for parks and gardens.

The Big Apple also revamped its recycling program, accepting all rigid plastics instead of just those numbered 1 and 2, and launched an electronics-waste recycling program that will make recycling more convenient by allowing apartment-dwellers to discard electronics in special recycling containers in their buildings.

Working with NRDC, professional and college sports leagues and teams are also continuing to work on sustainability efforts — including recycling — raising green consciousness among sports fans. The San Francisco Giants won this year's Green Glove Award from Major League Baseball, keeping an impressive 86 percent of their waste out of landfills.

4. U.S. fuel-efficiency standards are paying off

In the traditional gasoline engines that power most cars on the road today, only four out of every 20 gallons of gas actually go towards moving the vehicle forward. Newer engines — whether hybrid or conventional — are a lot more fuel efficient. Last year's landmark federal fuel-efficiency standards are already showing results. The EPA reported that model-year 2012 is the most fuel-efficient ever for the U.S. fleet, with an average of 23.6 miles per gallon. More than half-a-million conventional hybrid vehicles were sold in model-year 2013, and plug-in electric vehicle sales more than doubled from model year 2012 to model year 2013. More than a quarter of 2013 models are already ahead of schedule in meeting fuel-efficiency and carbon-pollution requirements. By the time the full standards are in effect in 2025, they'll reduce U.S. oil consumption by more than two million barrels — about half U.S. daily imports from OPEC — every day.

5. U.S. cities and farms are getting smarter about water

In hundreds of cities, a fraction-of-an-inch of rainfall can overwhelm sewer systems and trigger the discharge of sewage into waterways. This is more than an inefficient use of water; it's one of the biggest sources of water pollution in the country, leading to hundreds of days of beach closures and swimming advisories. These closures are a waste of time for beachgoers, as well as a wasted opportunity for local businesses. In Chicago alone, swim bans cost the local economy an estimated $2 million every year.

This year, several major cities, profiled in an NRDC report, moved ahead with big plans to combat stormwater pollution by using a smart, cost-effective solution called green infrastructure, which uses natural techniques, like green roofs, rain gardens, street plantings and rain barrels to capture rainfall and allow it to evaporate or soak into the soil.

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Washington, D.C. announced this year that housing developments over a certain size will be required to retain the water from a 1.2-inch storm on site, a move that is expected to expand the use of green infrastructure in the U.S. capital. In Seattle, the mayor directed city agencies to develop a green-infrastructure plan that can manage 700 million gallons (about 10 Olympic-sized swimming pools' worth) of stormwater runoff. And in Milwaukee, the city's Metropolitan Sewerage District put together a detailed regional plan to use green infrastructure to capture 740 million gallons of storm water every time it rains.

Meanwhile, in rural areas, American farms are paralyzed by droughts because their degraded soils have lost the ability to retain water. Soil matters, as my NRDC colleague Claire O'Connor and the United Nations Environment Programme both highlighted in reports last year. Both called attention to the benefits of practices that can regenerate starving soils. For example, cover crops, which are typically planted after the harvest of a main crop, protect soil from harsh winter weather and increase its ability to filter and retain water. [Building a Drought-Proof Farm (Op-Ed)]

NRDC is pushing the government to give cover-cropping farmers a discount on crop insurance — like a good-driver discount — since they're less likely to suffer losses during years of drought or other extreme weather. As more farms start using water-smart practices like cover crops, the nation will build a more resilient food system, protect farmers and save taxpayer money on crop-loss payouts.

Lehner's most recent Op-Ed was "Coffee Farms Falter as the World Heats Up." This Op-Ed was adapted from a post that appeared as part of Lehner's Wasteland series on the NRDC blog Switchboard. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on LiveScience.