Last week non-biodegradable plastic shopping bags were officially banned in Mexico City, making it the second largest metropolitan area in the Western Hemisphere to ban plastic bags. In March, Mexico City’s local assembly passed a law requiring stores in the world’s 11th largest city to provide biodegradable bags. There is a one-year grace period before authorities will impose sanctions. The grace period gives merchants time to come up with alternatives and for plastic bag producers to convert their factories.
“The challenge as always is how the law is applied,” said Beatriz Bugeda, the head of Citizen Observers of Environmental Vigilance. “You go to the markets and they put every fruit in a plastic bag. You can leave with 20 or 30 bags. More than waiting for penalties, I think the challenge is convincing citizens to change their habits. We have to go back to our grandmothers’ habits.”
Last year, Wal-Mart set the goal of reducing the amount of plastic bags it hands out in its Mexican stores by 50 percent by 2013. Wal-Mart plans to meet its goal by handing out 237 million less bags each year. Wal-Mart subsequently set a goal of reducing the amount of plastic bags it hands out in all its stores by 33 percent by 2013.
“By reducing the number of plastic bags our customers use, increasing the availability and affordability of reusable bags and providing recycling solutions, we think we can eliminate plastic waste equivalent to 9 billion plastic bags per year from our existing stores alone,” said Matt Kistler, senior vice president for sustainability of Wal-Mart Stores, Inc.
Kistler echoed what Bugeda said about changing people’s behavior. “If we can encourage consumers to change their behavior, just one bag at a time, we believe real progress can be made toward our goal of creating zero waste,” he said.
Are biodegradable bags really eco-friendly?
Mexico City’s ban only applies to non-biodegradable plastic bags. The European Recyclers Association warned in June that biodegradable plastic bags “have the potential to do more harm to the environment than good.” A study by the Biodegradable Products Institute found that the breakdown of bags depends on temperature and humidity. The bags break down slower in cold weather, and high humidity stops the process.
It is best if biodegradable bags are composted, and may produce methane if sent to a landfill. Methane is a greenhouse gas (GHG) with a warming potential 23 times greater than carbon dioxide. The Oxo-Biodegradable Plastics Assocation warns that biodegradable plastic should not be sent to landfills.