Estimates of worldwide plastic bag consumption top out around 1 trillion per year, or close to 2 million bags per minute. Americans use 100 billion disposable bags yearly—over 330 bags per person—and recycle only 0.6 percent of them.
Pollution and natural resources
Plastic (polyethylene) shopping bags are made from petroleum, a non-sustainable resource whose extraction and production has caused major environmental damage to soil, surface and ground waters, and local ecosystems. The production of petroleum also contributes to global warming and pollution: about 71 million pounds of toxins are released into the air and water annually during petroleum refinement. The plastics industry as a whole releases millions of pounds of toxic waste into the air, water, and soil each year, and represents 7 percent of the 5.7 billion pounds of toxic chemicals dumped by all manufacturers each year.
Paper bags actually cause 70 percent more air pollution and 50 percent more water pollution than plastic bags. Most paper bags are made from virgin pulp, which contributes to deforestation and loss of biodiversity. In 1999 alone, it is estimated that over 14 million trees were cut down to produce 10 billion paper shopping bags in the United States. This means there are fewer trees to serve as a sink for greenhouse gases like CO2, while the energy use associated with paper bag production or recycling increases those same greenhouse gas levels in the atmosphere.
Landfill waste and litter
When paper and plastic bags are discarded after a single use, they persist in the environment for up to 1,000 years. When it comes to disposal, one paper bag actually generates 72 percent more landfill waste than two plastic ones. But, as polyethylene plastic bags photodegrade over periods of up to 1,000 years into smaller and smaller particles, they create what can be described as plastic dust, which is harmful to animals that ingest it. Polyethylene particles work their way into the foodchain via filter-feeding marine organisms like jellyfish and salps. Plastics have the ability to concentrate harmful hydrophobic pollutants, such as DDT and PCBs, at up to 1 million times the rate at which they are found as free-floating substances. When plastic bags do not make it to the landfill and instead end up as litter in our waterways, they harm marine creatures, such as sea turtles and whales, clogging the digestive system of animals that ingest them.
Biodegradable plastic bags can be made from polylactic acid (PLA), which is produced from renewable resources such as corn, wheat, sugar-beets, or other vegetable products rich in starch. PLA is both biodegradable and bioresorbable, which means that biological systems are able to break it down and assimilate it. While PLA breakdown products will not contaminate the food chain in the long-term (as with polyethylene), PLA bags still may threaten wildlife when discarded into the environment as litter. Criticisms of PLA include the use of fossil fuels in its production (harvest and transport of corn), relative high cost, the need for an industrial composting process for use in its breakdown, and its release of greenhouse gases (CO2 and methane) upon biodegradation. When these bags are buried in landfills, the amount of sunlight and air exposure they receive is normally insufficient, and they may still take months to years to biodegrade.
- DDT:Dichloro-Diphenyl-Trichloroethane , or DDT, is a hydrophobic pesticide used for insect control.
- PCB: Full name Polychlorinated Biphenyls, PCBs are chemicals that are highly-toxic, persistent organic pollutants that contaminate waterways and accumulate in fish populations, working their way into the human food chain.
- photodegradation: The breakdown of a molecule (like LDPE polyethylene) into smaller pieces due to the absorption of a photon from sunlight's infrared, visible, or UV light, resulting in a fine particulate dust.
- polyethylene: A non-biodegradable substance, consisting of long chains of ethylene, used to produce materials with different densities, strengths, and flexibilities.
- Plastic Debris - Rivers to Sea
- Mindfully.org - Berkeley Plastics Task Force report 1996
- CNNMoney.com: Saving the World - One Plastic Bag at a Time
- Plastic Shopping Bag Free: Reports on worldwide plastic bag laws and bans.
- Social Pages - No.110 v.9 - Regd. n. SS-892. "Plastic bags," by Nasreen Abdullah
- FastCompany - Giving filmy, flimsy plastic the sack: Blog about cities and countries that are regulating plastic bag use
- Reusablebags.com - Facts and figures regarding the true cost of plastic bags
- Worldwatch Institute - The Good Stuff?
- Washington Post - Paper or Plastic?
- Reusablebags.com - Paper Bags Are Better Than Plastic, Right?
- Marine Conservation Society (UK) - Long Term Impacts of Plastic Bags in the Marine Environment (2004)
- Institute for Lifecycle Environmental Assessment - Paper vs. Plastic Bags