We need some clear thinking on plastic bags - Part 1

I've been observing the debate about plastic bags for years but haven't posted anything on it.

I'm agnostic about whether something really needs to be done about plastic bags in particular.

Good environmental policy, it seems to me, looks at the best ways of fixing identified problems - rather than targeting certain products.

So what are the problems with plastic bags? As I understand it:

• they're a large componenet of litter;
• they're a reasonably important component of waste / landfill;
• they get into waterways where they harm marine life;
• they're made from a non-renewable resource.

To my mind, a more sensible starting point is to look at each of these problems separately.

Let's start with threats to marine life. What are the big threats? What's the most effective way to reduce their impact? Will getting rid of plastic bags make a big difference? These are the questions we should be examining.

Let's look at litter. What are the problems it causes? What are the main components? What are the most effective ways to reduce it?

Ditto for landfill and ditto for non-renewable resources.

I suspect that there's more effective measures to deal with these issues by looking at all contributors to a problem than singling out one product.

I also suspect that plastic bags are being targeted because they're a visible consumer product. The only concrete regulatory measure that the Howard government announced to reduce greenhouse emissions was phasing out incandescent light globes. Now it's a start and probably worth doing but will make an extremely modest contribution. I suspect they chose that because it's something everyone sees and has experience with - people will notice they're dong something. Similarly, Australian governments have had difficulty coming up with solutions to water shortages other than water restrictions on households. Again, a modest measure that looks to the average person like you're doing something, but really does little to fix the underlying problem.

Targeting plastic bags without examining why also creates confusion. Are biodegradable bags a good alternative? Queensland seems to think so. But my understanding is that they take months or longer to break down and in the meantime they create the same litter problems and danger to marine life that plastic bags do. And while they use renewable inputs (eg corn starch rather than petroleum), there's no guarantee that the overall environmental impact of those inputs is any lower: growing corn has its own problems in terms of resource use (think cleared land, water use, petroleum-based fertilisers, petroleum-fueled tractors) and waste (think fertiliser and pesticide runoff - what does that do to aquatic and marine life?). So deciding on alternatives really depends on what we're trying to achieve.

It's tempting to look at energy waste and think 'let's ban old-school light bulbs', to look at water problems and think 'let's water the garden less' and see litter and think 'let's ban the bag'. And yes, we all need to do our bit and those measures probably do some good.

But the challenge for good policy and what will produce real outcomes is to do the hard thinking about what are the real causes of the problem and what are the most effective measures we can come up with to deal with them - not just to go with whatever grabs our attention.