China is banning the distribution of free plastic shopping bags, effective this June. Australia says it will phase out plastic shopping bags by the end of 2008. These moves are just the latest in a string of official actions to restrict the use of plastic shopping bags.

Tanzania, Kenya, Uganda, major cities in India and Bangladesh and a growing number of towns in the United Kingdom have banned them. Ireland and South Africa have imposed steep taxes on them. And in North America, bans have been put in place in a number of cities, from San Francisco to Leaf Rapids, Man.

What explains this global movement against plastic shopping bags? Environmental concerns, of course.

Many assume that such rapid and widespread shifts in environmental policies around the world can only be the product of an international treaty or, at the very least, the outcome of a highly organized international campaign by leading environmental organizations. But, in the case of plastic bags, the movement appears to be largely local and largely ad hoc.

There is some debate over the environmental impact of plastic bags, particularly with respect to the amount of energy they embody when compared with other options. But the specific rationales for regulations against plastic bags often have been driven by very local concerns.

Most of the local reasons given for reducing bag use have to do with their sheer volume and long-term persistence. The Washington-based Worldwatch Institute estimates that 500 billion plastic shopping bags are distributed and discarded every year, each of which can take up to 1,000 years to break down.

In India, discarded plastic bags on roadsides were being ingested by free-ranging cows, resulting in many deaths of the animals. In Dhaka, plastic bags were found to be the culprits in serious flooding by clogging sewer drains.

In Australia and Ireland, both countries that rely on the beauty of their coasts to attract tourists, there was a desire to present a clean image, as plastic bags were making up a significant amount of coastal litter. People there were also concerned about the dangers posed to marine life that can ingest, or get tangled in, plastic bags.

In a number of African countries, there are worries that plastic bags can act as breeding grounds for malaria-carrying mosquitoes. Plastic bags in China are known as "white pollution" because they are carelessly discarded in the streets.

San Francisco, in passing its ban, cited concern not just over litter and danger to sea mammals but also greenhouse-gas emissions associated with plastic bags, which are petroleum-based products. Leaf Rapids was worried about litter as well as the fact that household waste in thin plastic bags appeared to be attracting bears to its dump.

The global trend away from plastic bags has been bolstered by the fact that some retailers have been supportive. Some British retailers have backed voluntary bans, and several large chains in Canada and the United States have said they will stop handing out free plastic shopping bags altogether.

In many countries, the plastics industry prefers voluntary measures to control plastic bags through reuse and recycling, and opposes taxes and outright bans. Last year, Ontario and retail and industry groups voluntarily agreed to cut bag use by half over the next five years. The Ontario government noted that, if the voluntary measures are not successful, it will consider more stringent regulatory action.

The global shift in regulations vis-à-vis plastic bags demonstrates that rapid changes in governance practices around the world on environmental issues can take many forms, and can occur at many levels.

Internationally negotiated, top-down approaches may attract a lot of attention but don't always yield tangible results. Environmental initiatives that spring from the ground up and emerge from local concerns can collectively result in a powerful global impact, even without an internationally organized treaty or campaign.

The opinions expressed in this article/multimedia are those of the author(s) and do not necessarily reflect the views of CIGI or its Board of Directors.