How green is that bottle?

Daniel Goleman & Gregory Norris, Straits Times 21 Apr 09;

EARTH Day is tomorrow, and all things 'green' will be celebrated. But how environmentally friendly are 'green' products, really?

Consider that paragon of eco-virtue: the stainless steel water bottle that lets us hydrate without discarding endless plastic bottles. Using a method called life cycle assessment, we have evaluated the environmental and health impact of a stainless steel thermos - from the extraction and processing of its ingredients to its manufacture, distribution, use and final disposal. There were some surprises. What we think of as 'green' turns out to be less so (and, yes, sometimes more so) than we assume.

# Extraction, processing: Producing stainless steel requires a global supply chain involving more than 1,400 steps. For example, the mining of chromium ore, an essential component of stainless steel, can expose workers to a heightened risk of cancer. Next, the ores have to be processed to extract useful metal. This usually involves energy-intensive heating, a process that not only requires enormous amounts of fossil fuel but also releases greenhouse gases, carcinogens, particulates and toxic material.

# Manufacture: Making stainless steel results in about 10 times more pollution than regular steel. But if the steel mills use recycled iron, instead of newly mined pig iron, the environmental and health impact can be reduced by 10 per cent to 15 per cent. In addition, simple innovations like a lighter single-wall design - rather than the double walls typically found in insulated bottles - can reduce the ecological impact by about 35 per cent.

# Distribution: The bottle's journey from factory to distribution centre to you uses up energy and results in particulates, greenhouse gases and other emissions. The good news: shipping the bottle from a factory in Asia in a tightly packed cargo container, plus a few hundred kilometres by truck, adds only 1 per cent to 5 per cent to the environmental burden. The bad news: the heating, cooling, lighting and ventilation of the store where you buy the bottle could have nearly as much of a negative effect on the environment as producing the bottle itself.

# Use: Obviously, one danger of any reusable water bottle is bacteria build-up, so you have to keep it clean. If you wash your stainless steel water bottle in a dishwasher that uses a half-litre of electrically heated water, 50 to 100 washes can result in the same amount of pollution that was caused by making the bottle in the first place. Washing it in cold water still demands electricity to pump the water and chemicals to treat it - but the impact is tiny by comparison.

# Disposal: Steel lasts forever. Try to ensure that the discarded bottle finds its way to a steel recycler - not just to a landfill, where it could sit for centuries. By recycling, you return not only steel but also nickel and chromium alloys to the production chain, reducing the need to mine and process more of these ingredients. These benefits are well worth the impact of transporting the steel back to the mill for recycling.

So, is stainless steel really better than plastic?

One stainless steel bottle is obviously much worse than one plastic bottle. Producing that 300gm stainless steel bottle requires seven times as much fossil fuel, releases 14 times more greenhouse gases, demands the extraction of hundreds of times more metal resources as well as causes hundreds of times more toxic risk to people and ecosystems than making a 32gm plastic bottle. So if you're planning on only one water bottle in your life, buy plastic.

But chances are that buying that stainless steel bottle will prevent you from using countless plastic bottles. And think of the harm done to the environment by making more and more plastic - the electricity needed to form polyethylene terephthalate resin into bottles, the fossil fuels burned to produce this electricity, the energy used and emissions released from mining the coal and converting crude oil to fuel, and on and on.

What it comes down to is this: If your stainless steel bottle takes the place of 50 plastic bottles, the climate is better off; if it gets used 500 times, it beats plastic in all the environment-impact categories studied in a life cycle assessment.

But before stainless steel thermoses, before bottled water, we already had an eco-friendly method of getting water: drinking fountains.

Daniel Goleman is the author of Ecological Intelligence: How Knowing The Hidden Impacts Of What We Buy Can Change Everything. Gregory Norris is a lecturer at Harvard University and a professor at the University of Arkansas.

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