All life onEarth depends on theenvironment. Thenatural resources that come from the environment include food, water, plants, and minerals. Sustainability is the idea that humans must interact with the environment in a way that ensures there will be enough resources left for future generations.

There are now more than seven billion people on Earth. These billions of people use the planet’s resources every day. Human activity has harmed the environment in many ways. Some of the resources that people use cannot be replaced once they are used. People also use huge amounts offossil fuels, which has led topollution and other problems. Sustainability addresses ways to protect andconserve the environment.

In order to achieve sustainability, humans need to think about their decisions in almost every aspect of daily life. This applies to people’s individual actions as well as to the actions of industries.

Industries—such asmanufacturing,agriculture, andconstruction—depend on fossil fuels (coal,oil, andnatural gas). These fuels createpollution that affect the land, air, and water. Burning fossil fuels also leads to the production ofgreenhouse gases. These gases contribute to a problem calledglobal warming. Fossil fuels are nonrenewable resources. Once they are used up, they will be gone forever. To achieve sustainability, industries are starting to focus on usingalternative energy sources, such assolar power,wind power, andwaterpower. These energy sources are renewable, which means they cannot be used up. They also produce little pollution.

Construction requires a large amount of steel, concrete, wood, and other materials. One way construction can be made more sustainable is by using recycled materials, such as metals and concrete from demolished buildings. Sustainable building design, or green architecture, focuses on making sure each structure wastes as little energy as possible. For example, some buildings are designed to collect and store energy from sunlight to use in heating the building. Builders can also install a “cool roof” made with materials that absorb less heat than a traditional roof. This keeps the building cooler during hot weather.

Water conservation is very important, especially in agriculture. Agriculture uses about 70 percent of the world’s fresh water. Farmers can conserve water by planting crops that are suited to the climate where they are planted. Farmers can also collect rainwater and use it for irrigation.

Individuals also can change how they use energy and what products they buy and use in order to work toward sustainability. For example, people can install solar panels on their house. Solar panels use power from the sun instead of electricity generated by power plants that use coal. People can buy appliances, such as dishwashers and washing machines, that are designed to reduce water usage.Plastic, a common household material, creates many environmental hazards. Plastics do not break down, so they take up a lot of space in landfills. A great deal of plastic also winds up in the oceans, where it hurts theecosystems. People are encouraged to not use as much plastic and torecycle the plastic they do use. Glass, paper, and other materials can also be recycled. Like industries, people are encouraged to not usefossil fuels. They can bike, walk, or take public transportation instead of driving their cars.

Human activity can lead to a loss ofbiodiversity. Biodiversity is the variety of the animals and plants in any environment. It is lost when land is cleared for housing, when water is rerouted from its natural course, or when new species are introduced into an ecosystem. Plants are killed, and animals either die or have to find a new habitat. Sometimes entire species become extinct. Biodiversity is important because the different plants and animals in an ecosystem each play a role in keeping the ecosystem active and healthy. Sustainability must be practiced in order to maintain biodiversity.