Myth: Monarchs and GMO Foods Are Unrelated

Why North America Is Losing in the Monarch Games

Wanna talk Olympic pursuits? Every fall, monarch butterflies in eastern North America embark on an epic journey. Putting in 50-100 miles a day, they travel up to 3,000 miles from the U.S. and Canada to the fir forests of Mexico’s Neovolcanic Mountains, where they settle in for a few months of subtropical sun before winging it back north in March.

Monarchs cluster on fir boughs in central Mexico (Sweet Briar College)
Monarchs cluster on fir boughs in Mexico. (Sweet Briar College)

Ground zero for scientific study on this more than 10,000-year-old migration is Mexico’s Monarch Butterfly Biosphere Reserve, a World Heritage site, where an estimated 95 percent of the eastern monarchs spend the winter, making it, as UNESCO puts it, “the most dramatic manifestation of the phenomenon of insect migration.”

This winter, though, monarchs are occupying the smallest area they have since scientists started measuring 20 years ago, according to a new report by the World Wildlife Fund-Mexico.

As of the December 2013 count, monarchs have populated just 1.65 acres of the forest—compared with close to 50 acres in 1995—and are down 43.7 percent from 2012. (For the record, scientists can’t physically count the butterflies, so they use the geographic measurements to estimate population size. At 20 million butterflies per acre, this year’s population is estimated at only 33 million monarchs compared to a peak of 1 billion in 1996, according to Journey North.)

One of the foremost monarch scientists, Lincoln Brower, PhD, has been studying monarchs since 1956 (Sweet Briar College)

One of the foremost monarch scientists, Lincoln Brower, PhD, has been studying monarchs since 1956 (SBC)

To state it bluntly: “It’s pretty pathetic…I’m not sure what’s going to happen,” says monarch expert Lincoln Brower, PhD, professor at Sweet Briar College in Virginia and professor emeritus at University of Florida. “There has been a statistically significant downtrend, which in the last five years has become fairly precipitous. This past year, it’s not only the total number of [acres] that are way, way down, but also the fact that only one colony had a significant number of butterflies.”

Compared to “the good old days,” when monarchs formed three or four colonies per mountain, it’s plain to see eastern monarchs are experiencing a real population crisis.

On that not-so-uplifting note, let’s dig in…with some more expert insight from Brower on the whys, the hows, and—most definitely—the now-whats.

Three Forms of Competition for Migrating Monarchs

First, let’s talk geography. How do we know the mighty monarchs haven’t just settled on another, trendier vacay spot? Brower says that within the Reserve’s 12 mountains, new generations generally form colonies within just a few feet of where their predecessors did in previous years.

A handy map of monarchs' fall migration patterns, created by USGS National Atlas.

A handy map of monarchs’ fall migration patterns, created by USGS National Atlas.

In other words, though it is a mystery how they navigate their way to these spots, the destination selection is no passing trend.

So, if monarchs aren’t simply changing course, why aren’t they where they should be now? According to the WWF report, Bower, and supporting studies like this Conservation Biology article, there are three primary threats to eastern monarchs.

  • Deforestation and forest degradation. Though it is illegal, clear-cutting in Mexico’s mountains has been a problem in years past. The good news is that widespread logging has been steadily decreasing since 2007. Still, forest degradation remains a threat, with smaller-scale cutting and tourism both adding stress to the ecosystem.
    Milkweed, aka Home Sweet Home for monarch larvae. (National Wildlife Federation/Larry Lynch)

    Milkweed, aka Home Sweet Home for monarch larvae. (National Wildlife Federation/Larry Lynch)
  • Loss of breeding ground. Adult monarchs can feed on the nectar of all kinds of flowers—but they breed only where milkweeds are found. That’s because for monarch babies (aka larvae, aka caterpillars), milkweed is their host plant, where they eat, develop, build forts, etc. Unfortunately in the Midwest, where milkweed had long been prevalent, the overwhelming majority of soybean and corn crops have in recent years been genetically modified to withstand herbicide spraying—effectively squeezing milkweed out of the picture.
  • Severe weather. Cold snaps, major storms, and drought can all have an impact on monarchs’ year-to-year populations, making the implications of global warming a growing concern. In particular, in the Neovolcanic range, increasing drought can lead to disease in the firs and pines where butterflies settle.

Indeed, all three factors pose clear and present danger. But several scientists are saying that one outweighs the others.

First-place Threat: GMOs

“This decline has come on so fast that it really points to a loss of habitat due to GMOs with herbicide resistance,” states Brower. Another reason to point the finger at GMOs is because this decline is also coinciding with a slowdown in deforestation, which should actually be supporting population growth. And while extreme weather no doubt plays a part in population from year to year, he adds, looking at migration trends alongside weather charts (which, FYI, you can do at Journey North) shows that bad weather has not been as consistent a problem as sheer lack of breeding habitat.


A monarch butterfly enjoys the nectar of plants in the milkweed family. (Chicago Botanic Garden)

The numbers back up this perspective. According to the WWF report and this Insect Conservation and Diversity paper, more than half of the butterflies that overwinter in Mexico have typically come from the Midwest, where milkweed once flourished along the edges or in between rows of even the biggest agricultural fields.

In recent years, however, the growth of milkweed in the Midwestern landscape has nosedived—to the tune of a 58 percent decrease between 1999 and 2010. This coincides with, wait for it, an estimated 81 percent decline in monarch production in the Midwest.

The loss, researchers say, also coincides with the increased use of glyphosate, a non-selective, systemic weed killer that was brought to market by Monsanto as Roundup (though now that Monsanto’s patent has run out, you can find it in many other products as well). Why the increase in glyphosate use, you might ask? Glyphosate-resistant seeds, aka Roundup-Ready seeds, have been wildly popular with U.S. farmers because it enables them to kill all the weeds (including, you guessed it, milkweed)—without killing any of their crops.

In fact, according to the USDA’s Recent Trends in GE Adoption, a whopping 93 percent of planted soybean acres are now herbicide-tolerant, as are 85 percent of cornfields. GE-chart-USDAAnd in another interesting correlation, according to the EPA’s last, um, round-up of most commonly used pesticides in the U.S., glyphosate clocked in at numero uno with 180-185 million pounds being sprayed per year—more than twice the amount used in 2001.

Statistical coincidences? While more research may be needed to determine the full extent of the connection, there is certainly a growing body of evidence that the rise of GMOs is contributing to the decline of monarch populations.

And though the topic is a heated one in the U.S., at least two of the nation’s most respected monarch experts, Brower and Karen Oberhauser, PhD, have gone on record with strongly stated positions, citing the cultivation of genetically modified crops as the “number one culprit” and the “the smoking gun,” respectively.

Still, no matter which threat is of most concern, the combination of reduced breeding habitat, severe weather, and deforestation is certainly making it a tough time for monarchs these days.

Overwhelmed yet? Take heart! The good news is there are a lot of ways you can help these magnificent little insects.

How to Help Monarchs Win

Wanna lend a hand, ahem, wing to monarchs? Here are just a few ways you can go for the gold:


  • Engage in citizen science projects like Journey North’s monarch counts or Monarch Watch’s way stations program, to help scientists learn more about current population trends.
  • Learn more about genetically modified food, and ask your representatives to support labeling legislation. (According to this Center for Food Safety map, our continent is a little behind on this.) No matter where you stand on the issue, we think the more information, the merrier.
  • Support roadside habitat—ask your county managers not to spray the roadside with herbicide, and you’ll help create habitat for butterflies.
  • Let milkweed grow in your own yard—and encourage your neighbors to do the same.

EcoMyth Outcome: Myth busted

Declining monarch butterfly populations and the rising use of GMOs in agriculture are closely linked. As herbicide-resistant corn and soybean crops take over more of the monarchs’ traditional breeding grounds, they are wiping out the milkweed that monarch larvae depend on for food and shelter.

Do You Need to Wash Your Recycling?

It’s time we had a little talk. Sometimes in life, we have dirty things we want to, ahem, recycle. This can mean we have to rinse containers before recycling them…except for when we don’t. Well, it’s certainly clearer than it used to be. But, the need to rinse really depends on the local recycling provider in your area. More often than not, though, a light rinsing is called for.

It used to be that some cities, such as Chicago, didn’t need residents to rinse their recyclables. The services took on the job of cleaning recyclable materials themselves. But Chicago and more areas like it now ask residents to remove the bulk of food residue.

This change is likely due to the potential contamination of paper, now that many recyclers have moved to curbside “single stream” recycling – where glass, plastic, paper and cardboard no longer need to be sorted into separate bins at home.

Another benefit of rinsing is that good washing helps deter rats and insects from trying to get at the recyclables before pick-up.

Even within facilities operated by the same waste management company, rules vary by location. That’s because the washing, sorting, and recycling equipment is continually being upgraded, improving its ability to handle more types of containers.

How Clean Do Those Containers Need to Be?

But it’s not that complicated. Waste Management, Inc. the largest recycling company in the world, says this about rinsing recyclable containers:

While all bottles, cans, and containers should be clean, dry, and free of most food waste before you place them in your recycling container, they don’t need to be spotless. The goal is to make sure they are clean enough to avoid contaminating other materials, like paper. Try using a spatula to scrape cans and jars, or using a small amount of water, shake the container to remove most residue.

Republic Services, Inc., another of the largest recyclers in the U.S., provides some simple recycling rinsing guidelines, and very easy to understand reasons for the rinse:

“Recyclables must be empty, clean and dry to prevent the contamination of other recyclables in the collection truck and at the recycling processing center. 

One ketchup bottle or not quite empty milk carton can cause your entire bin of otherwise perfectly recyclable items to be contaminated. Why? Because if the milk or ketchup leaks onto any paper, the paper is no longer recyclable. In some cases, the load won’t be accepted at many commercial processors. So, yes, it may end up in the trash.

“Unfortunately, contaminated materials have to be sent to the landfill, making your recycling efforts null and void.” But it’s easy to prevent this from happening by following these three steps:

Rinsing Recyclable Containers – Three Easy Steps

Step #1 – Empty.  
First, empty all liquid and residue from food and beverage containers. This makes a big difference for the next step.     

Step #2 – Clean.
Once excess liquids or solids are removed, give the containers a quick rinse – if needed – to clear any remaining residue. A rinse is usually needed for packaging that held milk, juice, sauces and condiments. A thorough wash isn’t called for, even here. No dish soap is necessary – a quick rinse and swish will do! 

Step #3 – Dry.
Now that your recyclables are empty and clean – let them dry out. They can sit upside down in the sink for a bit. Just don’t put wet containers in the bin.
And don’t stress if a little water remains. The rule of thumb is to never leave more than a teaspoon of liquid in a container. This will usually evaporate before your recyclables get picked up. 

Fortunately the answer in other areas is just a click away, thanks to Earth911’s recycling database, also available by app, which has compiled nationwide guidelines by zip code. Just enter the container type you want to recycle, and your ZIP code, and the search will identify the recycling facilities available for you. Then, check out the recycler’s guidelines.

As you’ll note, these recycling guidelines almost always say, “Please empty and rinse all containers and do not flatten containers.”

Why Aren’t Rinsing Requirements Consistent?

Why do the service requirements differ at all? And what happens if you don’t follow your local guidelines? We posed those and other questions to Eric Masanet, PhD, a Northwestern University Energy and Resource Systems Analysis Laboratory professor and researcher, and editor-in-chief of science journal Resources, Conservation and Recycling. His short take: It’s smart to follow the rinsing guidelines in your area, but not necessary to stress if you sometimes forget.

What happens if you don’t rinse recycling?

One big FAQ from people whose recycling service recommends rinsing is what happens when you forget to do it. Will your jar/bottle/can/what-have-you end up in a landfill anyway?It’s a valid question given that Waste Management, which manages half the country’s curbside recycling programs, used to state on its website that one dirty item can contaminate thousands of pounds of collected plastics. These days, WM just advises, “While all bottles, cans and containers should be clean, dry and free of most food waste before you place them in your recycling container, they don’t need to be spotless. “

But, yes, as Republic Services’ website says, “One ketchup bottle or not quite empty milk carton can cause your entire bin of otherwise perfectly recyclable items to be contaminated.”

So, please go ahead and rinse out any remaining liquids, in particular.

But the fact that an item is contaminated doesn’t relegate it to landfill status, explains Masanet. The recycling facility will use a mix of people and machines to sort then purify or clean everything according to type. Metal is the least sensitive to contaminants, he says, while plastic is so easily contaminated that even residue from a label can alter its chemistry and affect the quality of the recycled material in the end—exactly why recycling facilities have robust cleaning processes in place.

The real issue here is contamination of paper products in the same recycling bin. So, it’s more important to remove liquids than solids, like peanut butter.

More Reasons to Rinse Recyclable materials

Another downside of dirty recyclables is that contaminated recycled material has less market value—which means the recycling service provider has less to spend on things like improving service and green technology. So even though the recycling police won’t arrest you for not rinsing, Masanet advises complying with local guidelines so that the system is most efficient.

Curious about how recycling works once it leaves your bin? Take this video tour of a single stream recycling facility in Philly, courtesy of Waste Management, the country’s largest recycling provider.

Is Rinsing Recyclables a Waste of Water?

Another concern people have is whether rinsing recyclables wastes too much water. Generally though, Masanet recommends recycling as an “environmental slam dunk,” for saving energy, resources, and pollution. Even when considering water use on your end and at the recycling center, recycling almost always leads to energy savings when we consider the water needed to produce virgin glass, steel, plastic, or aluminum.

To rinse at home, just scrape out the majority of any remaining food with a spatula, and rinse it. Better yet, after washing any dishes by hand, just quickly swoosh around your recycling in the dishwater you’ve already used. That’s good enough for bottles, cans, and jars heading for your recycling bin. That’ll also be enough to keep your recycling bin from getting too smelly. The recycling facility will provide any further rinsing.

And, you’re not wasting water in the process.

How Much Water Does Recycling Save?

Working with data from various sources, Masanet is able to draw some interesting conclusions.

  • For steel and aluminum, it takes 3-10 times as much water to produce virgin metals as it does to recycle them. In other words, even extensive rinsing won’t reverse the water benefits of recycling. (Supporting intel comes from EERE and the Aluminum Association.)
  • For glass, the water use of recycled glass is closer to that of producing standard glass, but still, we’re likely to save 1-2 pints of water for every glass pint bottle recycled. 
    Conclusion: Prudent rinsing should preserve the water benefits of recycling. (Info from a WRAP report.)
  • For PET and HDPE plastics, they are thoroughly washed as part of the recycling process given that they are sensitive to contaminants. Different life cycle analyses and different recycling processes lead to different conclusions about how much water recycled plastics save, with a range of negligible water savings to more than 30 liters for recycling a one-liter bottle. Masanet’s verdict: prudent rinsing is not likely to negate the water savings of recycling plastics, but reckless rinsing might. (Via WRAP.)
  • So rinsing is nearly always the better, green approach.

A huge point to keep in mind, reminds Masanet, is that saving water is only one of the many benefits of recycling. We also save energy, greenhouse gas emissions, and pollution to air and water. “So, even if we occasionally use more water than we should, the other environmental benefits really make recycling a slam dunk.”

Uncovering the Basic Rinsing Tips

To rinse or not to rinse may not always have a black and white answer (it usually is!), but here are a few general pointers, in those cases where rinsing is not strictly required:

  • Empty is preferable:
    • It’s greener to consume or at least trash the food/drink/cleaning product in containers before recycling them. In addition to attracting vermin and upping the ick factor in your bin for the brave personnel who have to handle it, excess debris in your recycling bin requires extra energy to clean and dispose.
  • Rinsing for single-stream recycling:
    • Combined bin peeps, (those with “single stream recycling” – which is becoming more and more the norm) it’s a good call to err on the side of rinsing, since paper and cardboard are especially sensitive to residue. If nothing else, though, it is important to dump all liquids out of containers to help keep the paper goods recyclable.
  • Conserve water when you rinse:
    • Scrape food out first with a wooden spoon or rubber spatula, then swish a little bit of water around in the container versus letting it sit under a running faucet. If you have several containers to rinse at once, just fill up a bowl and use the same water for the whole job.

EcoMyth Outcome: Myth Mostly True – You generally SHOULD rinse all recyclable containers

You really should rinse all containers prior to recycling, unless your local recycling provider says you don’t have to. Emptying containers and rinsing when it seems appropriate will help make the whole process more economical. The main thing is to find out best practices in your area and follow them as well as you can.

And, as always, if there’s a question, contact your local recycling facility by phone or visit their website. You’ll almost certainly learn something else interesting along the way.

Do One Green Thing


Type your zip code into Earth911’s curbside recycling guide for the simple do’s and don’ts in your area.

More ways to help:

  • Empty all containers prior to recycling them, to help keep paper and cardboard nice and dry.
  • Rinse conservatively–no need to go all Mr. Clean on that milk carton when a simple swish of water will do the trick.
  • Reduce use in the first place, as suggested by Masanet. How? Opt for items in bulk where possible.

The Multiplier Effect

If more people recycle their beverage containers, we’ll redirect salvageable stuff from the landfill and save resources needed for new material production. Here are three cool cases in point from the EPA:

  1. Five 2-liter recycled PET bottles produce enough fiberfill to make a ski jacket.
  2. Recycling one soda can save enough energy to run a computer for three hours.
  3. The energy saved from recycling one glass bottle will operate a 100-watt light bulb for four hours.

One More Thing…

A couple of more very important tips on recycling:

  • Great that you’re recycling! Next step – are you composting? Check out our guide to figuring out what’s compostable vs recycling.
  • Interested in composting those paper plates? Find out which paper plates are actually compostable (or not!)
  • Don’t put plastic bags in your recycling bin – ever. Bags are very likely to jam up the sorting equipment.
  • For any other potentially recyclable materials than the usual plastic bottles, cans, jars, paper and cardboard, be sure to check out your recycler’s website (or app!) to make something is recyclable.