If you feel you’re not doing enough for the environment by replacing your incandescent light bulbs with LED lights and composting your kitchen scraps, maybe you’re ready to make a deeper commitment to environmental stewardship.

Some of these strategies may seem a little radical, but they are among the most valuable actions you can take to protect and preserve Earth’s environment.

Have Fewer Children—Or None

Overpopulation is arguably the world’s most serious environmental problem because it exacerbates all of the others. The global population grew from 3 billion in 1959 to 6 billion in 1999, an increase of 100 percent in just 40 years. According to current projections, the world population will expand to 9 billion by 2040. This represents a slower growth rate than that of the last half of the 20th century, but it will nevertheless leave us with many more people to accommodate.

Planet Earth is a closed system with limited resources—only so much fresh water and clean air and only so many acres of land for growing food. As the world population grows, our finite resources must stretch to serve more and more people. At some point, that will no longer be possible. Some scientists believe we have already passed that point.

Ultimately, we need to reverse this growth trend by gradually bringing the human population of our planet back down to a more manageable size. This means more people must decide to have fewer children. This may sound pretty simple on the surface, but the drive to reproduce is fundamental in all species. The decision to limit or forgo the experience is a difficult one for many people because of emotional, cultural, and religious traditions and pressures.

In many developing countries, large families can be a matter of survival. Parents often have as many children as possible to ensure that some will live to help with farming or other work and to care for the parents when they are old. For people in cultures like these, lower birth rates will only come after other serious issues such as poverty, hunger, poor sanitation, and freedom from disease have been adequately addressed.

In addition to keeping your own family small, consider supporting programs that fight hunger and poverty, improve sanitation and hygiene, or promote education, family planning, and reproductive health in developing nations.

Use Less Water—And Keep It Clean

Fresh, clean water is essential to life—no one can live long without it—yet it is one of the scarcest and most endangered resources in our increasingly fragile biosphere. Water covers more than 70 percent of the Earth’s surface, but most of that is salt water. Freshwater supplies are much more limited and today a third of the world’s people lack access to clean drinking water.

According to the United Nations, 95 percent of the cities worldwide still dump raw sewage into their water supplies. Not surprisingly, 80 percent of all illnesses in developing countries can be linked to unsanitary water.

Especially if you live in a dry climate, you should use only as much water as you need, avoid wasting the water used, and strive to protect water supplies.

Eat Responsibly

Eating locally grown food supports local farmers and merchants in your own community as well as reducing the amount of fuel, air pollution, and greenhouse gas emissions required to move the food you eat from the farm to your table. Eating organic meat and produce keeps pesticides and chemical fertilizers off your plate and out of rivers and streams.

Eating responsibly also means eating less meat and fewer animal products such as eggs and dairy products, or perhaps none at all. Eating less meat is a matter of good stewardship of our finite resources. Farm animals emit methane, a potent greenhouse gas that contributes to global warming, and raising animals for food requires many times more land and water than growing food crops.

Livestock now uses 30 percent of the planet’s land surface, including 33 percent of farmland worldwide, which is used to produce animal feed. Every time you sit down to a plant-based meal instead of an animal-based meal, you save about 280 gallons of water and protect anywhere from 12 to 50 square feet of land from deforestation, overgrazing, and pesticide and fertilizer pollution.

Conserve Energy—And Switch to Renewable Energy

Walk, bike, and use public transportation more. Drive less. Not only will you be healthier and help to preserve precious energy resources, but you’ll also save money. According to a study by the American Public Transportation Association, families that use public transportation can reduce their household expenses by $6,200 annually, more than the average U.S. household spends on food every year.

There are dozens of other ways you can conserve energy. You can turn off lights and unplug appliances when they are not in use and substitute cold water for hot whenever practical. Other small steps you can take include weather stripping your doors and windows and not overheating or overcooling your home and office. (An added bonus is that a good office temperature also boosts productivity.) One way to start is to get a free energy audit from your local utility.

Whenever possible, choose renewable energy over fossil fuels. For example, many municipal utilities now offer green energy alternatives so that you can get some or all of your electricity from wind, solar, or other renewable energy sources.

Reduce Your Carbon Footprint

Many human activities—from using coal-fired power plants to generate electricity to driving gasoline-powered vehicles—cause greenhouse gas emissions that heat the atmosphere and contribute to climate change.

Scientists are already seeing significant climate changes that point to the likelihood of serious consequences. Some scenarios foresee increasing drought that could further reduce food and water supplies and, at the same time, rising sea levels that will submerge islands and coastal regions and create millions of environmental refugees.

Online calculators can help you measure and reduce your personal carbon footprint, but climate change is a global problem that requires global solutions and, so far, the world’s nations have been slow to find common ground on this issue. In addition to lowering your own carbon footprint, let your government officials know that you expect them to take action on this issue—and keep the pressure on until they do.

Edited by Frederic Beaudry