Cloth Diapers or Disposables? How to choose the one that will reduce your environmental impact the most

“Wait, you work in sustainability consulting?  And you use disposable diapers?”

Nobody has ever actually had the courage to say this to me, but they think it.  Or at least I imagine they do.

Anyway, yes – I work in sustainability consulting and my daughter wears disposable diapers.  Specifically, in my work I use a tool called Life Cycle Assessment, which helps us to understand the environmental impacts of a product or service from raw material extraction through manufacturing, consumer use, and disposal – so we can make better choices about the products we make and use.

This article may be a bit different from all the others I’ve seen on this topic in that I don’t come with an agenda.  I don’t believe you must use either cloth or disposable diapers to reduce your environmental impact – a much better question is ‘what environmental impact is most important to you?’ I’ll give you the data to help you decide which impact to prioritize, and thus which type of diapers may work best for you.  Because – and here’s the kicker – neither is clearly better for the environment than the other, so it’s up to you to apply your own principles to the available data to make your own choice.

1. Greenhouse Gas Emissions

The landmark study on the environmental impact of diapers was conducted by the UK’s Environment Agency in 2006 – this was an update from an earlier 2002 report.  (Seems like we’re due for another update, hey, guys?).  The study looked at a variety of environmental impacts but let’s just take greenhouse gases (GHGs) for now, which warm the planet and in my opinion are the most serious environmental problem the world faces.

There are several types of GHG emissions, some of which are more powerful than others.  Carbon dioxide is more prevalent than some of the more powerful ones like methane, which is more than 20 times as powerful a GHG as carbon dioxide.  So life cycle assessments convert all other types of GHGs to units of ‘carbon dioxide equivalent’ or ‘CO2e’ for ease of understanding.

The study found that the average family using disposables generates a global warming impact of 550kg CO2e over the 2 1/2 years a child is typically in diapers; this number decreased from a previous study conducted by the same organization due to manufacturing changes and a reduction in diaper weight.  The cloth diapers generated 570kg CO2e for a baseline scenario, which assumed washing at 60 degrees C (for the Americans that’s 140 degrees F) and that three quarters of diapers are line dried.  So the GHG numbers are pretty much a wash (as it were) between cloth and disposables in the U.K., but in the U.S. there a few more things to consider.

A. For disposables, we have to factor in a likely larger distance to landfills than in the U.K. The study doesn’t give us enough information to calculate this number, and it probably isn’t very big, but it does exist.  It may be offset by further assumed product lightweighting which has occurred since 2006 (which reduces transportation emissions of both new and soiled diapers).

B. For those considering cloth diapers in America, line drying 3/4 of the diapers you use is going to require a pretty big cultural shift.  I know very few people in the States who line dry, and I don’t think I’ve ever seen a diaper on a washing line.   Americans are also more likely to wash in hot water to be sure those germs are dead – mainstream (forum, blogger, diaper company and a soap company) advice advocates for hot washing.  But many Americans reduce the temperature of their water heater to 120 degrees F after having a baby to prevent scalding, so in the States we’d still be at the 60 degrees C scenario.  British people apparently just teach their kids about hot water…

Tumble drying all diapers increases the global warming impact by 43%, and washing at 90 degrees C instead of 60 degrees C increases the impact by 31%.    Combining these two scenarios results in a total of 970kg CO2e with very hot water use in the U.K vs. 550kg for the disposables..  For cooler water use in the U.S. but tumble drying every load we’re looking at 815kg CO2e over 2 1/2 years. Technological improvements to washers and dryers since 2005 has likely reduced this number somewhat, but probably not enough to equal the GHG emissions from disposables.  To put that into context, the difference between disposables and the U.S. cloth diaper scenario is the equivalent of driving about 630 miles, or switching seven incandescent light bulbs to CFLs (data on this comes from the EPA).  So not totally insignificant, but something you could easily offset by decisions you make elsewhere in your life.

A reasonable chunk of the emissions (GHGs and others) associated with cloth diapers occurs in the manufacturing of the cotton, which only happens once – no matter how many times the diapers are used.  So the best possible scenario for cloth is to wash in cold water, line dry, and then pass on the diapers to a second child.

2. Water

One thing life cycle assessments historically haven’t done very well is to consider the regional impact of different types of resource use pollutant emissions, and water is a very regionally-specific issue.  I live in California, where we’ve seen mind-boggling drought this year – our snowpack was at 5% of normal on April 1, 2015 – the lowest level since 1950, and it wasn’t much better last year.  The irony is that if you live in an area where line drying is feasible a majority of the time it’s likely that you’re also in a water-stressed area, so you have a trade-off between water and GHGs if cloth is appealing.  If you do live in a water-stressed area and you want to do what you can to minimize your water use, you should use disposables.

Cotton is usually grown in arid areas with large amounts of irrigation, so there’s also a large water impact in the manufacturing stage.

3. Landfill Space (and a bit more on GHGs)

One of the main arguments for using cloth diapers is the mountain of waste that disposables creates.  I can’t really argue with that; if your kid is going through 2,700 diaper changes a year then that really is an enormous amount of waste – actually it’s kind of sickening to think about.  Landfill space in the Northeastern U.S. is somewhat restricted due to the lack of political will to build new ones, and trash there tends to be shipped across state lines for this reason.  But the U.S. as a whole is not running out of landfill space – waste companies are actually expanding dumps faster than demand due to accounting rules that favor this approach.

Just as the cloth diaper industry likes to say, disposable diapers mostly do not degrade in a landfill and instead may sit there for 250-500 years.  From a GHG perspective this is actually preferable to degradation – if the diaper doesn’t degrade, then the GHGs in it are locked away in the landfill rather than being released to the atmosphere where they can contribute to global warming.  Because of the anaerobic (meaning “lack of oxygen” in a landfill), a biodegradable diaper that ends up in the landfill and does manage to degrade ends up producing a lot of GHGs, as the wood pulp and other organic matter turn into our old friend methane, the GHG that’s 20 times as powerful as carbon dioxide.

Biodegradable diapers that are composted in the presence of oxygen (i.e. not buried deeply) will degrade to carbon dioxide, which is better than methane but not as good as not degrading at all.

In some places, trash is burned to generate energy and under those circumstances, burning the disposable actually creates a small GHG ‘credit.’  Waste-to-energy is a whole other can of worms that I won’t go into here; it is probably safe trace amounts of pollutants do make it out into the air after the trash is burned.

It sucks that we need landfills to store all the stuff that we should be able to find some way to use again but can’t or won’t for economic or other reasons.  But if we accept that climate change is a bigger problem than landfill space, we cannot argue that we should use cloth diapers to reduce our environmental impact to the greatest extent possible.

4. Chemical Use and Exposure

There are a lot of chemicals involved in the manufacturing of both disposable and cloth diapers.  Everything is a chemical that may be hazardous at a high enough dosage: even water can kill you if you drink enough of it.  What we’re talking about here is chemicals that are known to be or may be hazardous to humans even in quite small doses.

An unusually well-written and -sourced Baby Center article describes the chemicals that are present in disposable diapers and that may be present as manufacturing residues as not sufficient to cause your baby any harm except in exceptional circumstances (i.e. a baby with hyper-sensitive skin).  The super-absorbent material (sodium polyacrylate) in nearly all disposable diapers appears to be mostly inert unless it is inhaled (which means you’d have to tear open the diaper).  Some people find their babies get a rash with disposable diapers and it’s possible that the sodium polyacrylate is to blame, but a journal article cited by BabyCenter found only one case with a potential connection.  In any case, if your baby is allergic to a product then you should stop using it and try a different one, but the vast majority of babies will not have an allergy problem with sodium polyacrylate.  The same goes for dyes and perfumes; most babies are unlikely to have a reaction but if yours does – or if you just don’t want to take the chance, use a different product.

Dioxins are formed when the wood pulp in diapers is bleached with chlorine, and dioxins are really nasty carcinogens.  From the same BabyCenter article: “There doesn’t seem to be enough dioxin in a diaper to threaten a baby’s health, however. In fact, it’s not even a close call: A study published in the journal Environmental Health Perspectives in 2002 estimated that kids get thousands if not millions of times more dioxins in their diet than they get from their diapers. (Dioxins are everywhere in the environment, and they end up in everything that we eat, especially animal fats).”  So to reduce your child’s exposure to dioxins, go vegetarian – and then worry about your diaper choices.

Chemicals are also used in cloth diaper manufacturing, of course – cotton is one of the most fertilizer- and pesticide-intensive crops to grow, and “seven of the 15 pesticides commonly used on cotton in the United States are listed as “possible,” “likely,” “probable” or “known” human carcinogens by the Environmental Protection Agency.”  It’s unlikely that any of these chemicals are still on the cloth by the time it gets to you, but farm workers and people living near fields are much more likely to be exposed to levels high enough to harm their health.  By buying organic you are stating that you care about the health of the people who live and work around cotton farms.

Organic cotton wins on the GHG front, too: a life cycle assessment conducted by the well-respected Stockholm Environment Institute found that organic cotton manufacturing produces about 3kg CO2 emissions per metric tonne of spun fiber, while conventional cotton manufacturing produces about 5.5kg CO2 per metric tonne of spun fiber.  (I’m averaging the numbers from scenarios based on Indian-grown and USA-grown fibers; the authors explain the differences between the two countries as primarily driven by the different mix of energy sources available in those countries but fail to explain why the USA-grown scenario produces fewer GHGs for organic cotton but more for conventional.)

5. Diaper rash and skin sensitivity

Our daughter Carys never got diaper rash when she was tiny – she never had the chance.  She would start screaming every time she peed, and we quickly learned that the indicator stripe (which changes color when wet) was the key to maintaining our sanity.  Sometimes she would start screaming and we’d check the diaper to find the indicator unchanged; when the screaming continued we would check again in thirty seconds to find the yellow indicator had turned blue – her response was literally faster than the indicator.

We thought she might have a yeast infection but we would watch her pee with no diaper on and she’d be fine; she just couldn’t stand it against her skin.  The amounts she was peeing were so tiny that when we tried diapers without an indicator (like most ‘eco’ disposable brands) we would end up changing them even more often because we weren’t sure why she was crying and couldn’t tell if she was wet.  At one point we were doing 16 changes a day and it was costing us a fortune.

Cloth diapers can cause diaper rash because the pee sits next to the skin (it’s rapidly pulled away from the skin by disposables) but regular changes will reduce the likelihood of this.  If your baby seems to be sensitive to the type of diaper you’re using, try a different kind.

I had actually bought some cloth diapers (from the consignment store, but they were in really good condition) before Carys was born – planning to cloth diaper after she grew into them.  A month in I pulled them out of the closet and put them in her diaper drawer, planning to try them the next day.  The next day rolled around and I was too scared – we were struggling with breastfeeding as well at the time, and her afternoon naps weren’t great either, and I wanted to know that if she was crying, it wasn’t because she was wet.  I kept thinking I’d try again the next day, and each next day I just didn’t dare do it.  She’s much less sensitive these days, and we mostly change on a rough schedule rather than because she just peed – but now we’re in seventeen month-old grown-up poop, not non-stinky newborn poop, and it’s a hard switch to make.  Which brings me to:

6. The poop

My husband is lovely, but my goodness he’s a wuss, and he has a ‘thing’ about poo.  He wore latex gloves for all diaper changes – even just the pee ones – for the first month.  I’m not joking.  There’s just no way he’s going to scrape or spray poo off anything and I knew that if I did cloth I was essentially signing myself up for doing the vast majority of diaper changes – and all of the associated laundry.  The disposables do occasionally start to smell in their can before we take them out but I knew he would think that the smell from cloth diapers waiting to be washed would be way worse, even if it objectively wasn’t.

7. The Cost

8. Market-Scale Considerations

The Upshot: