Reusable shopping bags are often considered better for the environment than single use bags. Plastic shopping bags have advantages and disadvantages when compared to paper bags.

Advantages

Compared to paper bags

• The United States Environmental Protection Agency says paper bags are worse for the environment than plastic. Plastic bags require much less energy to manufacture, ship and recycle and because of this plastic generates less greenhouse gas. Plastic bags cause less air and water pollution. They compress to a small size in landfills.
• Sterile method for transporting food products and preventing food borne illness
• Light weight nature requires less energy consumption during transportation compared to paper with a 7:1 advantage.
• Many studies comparing plastic bags versus paper bag show that plastic bags have less net environmental effect than paper bags, requiring less energy to produce, transport and recycle; however these studies also note that recycling rates for plastic are significantly lower than for paper.
• Plastic carrier bags can be reused as trash bags or bin bags.
• According to the Australian government most bags are reused as bin liners.
• Plastic bags can be recycled through some grocery store take-back programs
• When it comes to concerns about their impact on the environment The EPA was quoted in an interview saying…”consumers shouldn't stress too much, as long as they're recycling or reusing store bags, said Chris Newman, an environmental scientist with the U.S. Environmental Protection Agency.”

Disadvantages

• Plastic shopping bags are made from petrochemicals which are not renewable.
• When disposed of improperly, they are unsightly and endanger many forms of wildlife.
• Plastic bags, conventional or "compostable", do not readily biodegrade in a sanitary landfill as paper and other materials don't either.
• Plastic bags (particularly thin dry cleaning bags) can cause unsupervised infants to suffocate when not handled properly.
• the high volume to weight ratio of plastic means that the collection and transport of this waste is difficult and expensive,