Convenient and portable, laptop computers have become an ubiquitous product in modern life. Like other consumer electronics, however, laptops can have significant effects on the environment. Consumers should be aware of the environmental impact of laptops, in everything from their production to their carbon footprint to their disposal.

Making a laptop requires several environmentally unfriendly resources -- most notably, rare-earth metals. These materials are mined in China, which has lax standards on environmental protection but produces 97 percent of the world's rare-earths supply. Laptops also contain potentially dangerous lead in their batteries as well as polyvinyl chloride in wire coatings, which can emit toxic dioxin if burned.

Relative to other consumer goods, laptops do not consume much electricity, but they still have a carbon footprint. The University of Pennsylvania estimates that, depending on the model, laptops usually consume between 20 and 50 watts per hour of moderate activity. Even a laptop at the highest end of power consumption -- using 80 watts per hour -- would only produce 0.05 kilograms (0.12 pounds) of carbon per hour of use. Compare this to a dishwasher that consumes 3,600 watts and produces 2.4 kilograms (5.4 pounds) of carbon per hour.

When laptops become obsolete or break, they must be disposed of. The toxic materials within them then become part of landfills. Some laptop manufacturers, such as Dell, accept their old laptops as inputs for recycling programs, but the Environmental Protection Agency estimates that only 38 percent of computers in 2009 by weight were recycled. If laptops are not recycled, the lead, mercury and other toxic components can contaminate the groundwater near landfills, entering the environment.

While laptops have several problematic aspects, they are significantly greener than desktop computers. Desktops use much more electricity and therefore produce more carbon per hour than laptops. Desktops are also larger by weight, so they use up more resources. As long as the potentially toxic components of laptops, which are usually concentrated in the battery, are carefully managed in recycling programs, laptops are an environmentally preferential choice to full-size desktop computers.