Science

Roundup Hysteria

Misinformation about one of the safest herbicides ever produced has created a lucrative business for ambulance-chasing lawyers and NGOs—at the expense of native species.

Ground crews use machetes and glyphosate to free an Everglades tree island from the clutches of invasive Old World climbing fern. Photo © Jonathan Glueckert/University of Florida
Ground crews use machetes and glyphosate to free an Everglades tree island from the clutches of invasive Old World climbing fern.
Jonathan Glueckert/University of Florida

You’ve seen the ads flooding television and social media: “Have you been exposed to weed killer Roundup? If you have cancer, you may be eligible for compensation. Call our law offices … ”

In 2018 and 2019, California juries ordered Roundup’s producer, Monsanto, to pay multimillion-dollar compensations to four non-Hodgkin lymphoma patients who claimed to have been sickened by Roundup (one of dozens of formulations with herbicide glyphosate as the active ingredient). As a result, there are now close to 20,000 lawsuits against the company from people who also allege that exposure to Roundup gave them cancer.

The California verdicts will almost certainly be overturned on appeal because they were based on the alleged failings of Monsanto, not on any scientific evidence that Roundup causes cancer. Follow-up suits that aren’t settled are likely to fail, too.

All scientific bodies that have seriously studied glyphosate report no link to cancer. These include the World Health Organization. But WHO’s loosely connected appendage—the International Agency for Research on Cancer—postulates a “probable” link. Instead of studying glyphosate, it reviewed existing studies of the herbicide. Based on this 2015 review, IARC placed glyphosate on its “2A List” of substances with limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals” or, in IARC’s abbreviated translation, “probably carcinogenic.” That list also includes “very hot beverages” and “red meat.”

Lee Van Wychen, executive director of science policy for the National and Regional Weed Science Societies, offers this: “IARC’s review was such a crooked scam! I’ve never seen anything like it. … IARC cherry-picked a couple studies and on top of that fudged the results of those studies. They did these odds-ratio calculations—a correlation, not even a mechanistic cause—of how glyphosate might cause cancer. Now there are people on the conservation side who are afraid to use glyphosate.”

Van Wychen assesses the studies IARC reviewed that supposedly indicate “sufficient evidence of carcinogenicity in experimental animals” as follows: “They dosed rats with glyphosate to the point they couldn’t even stand up straight.” On Oct. 19, 2017, Reuters reported that IARC “dismissed and edited findings from a draft of its review of the weed killer glyphosate that were at odds with its final conclusion.”

The California verdicts, the lawyer feeding frenzy, and Roundup hysteria all issued from IARC’s speculation.

The week IARC published its minority opinion the review’s leader, Christopher Portier, who served as a special adviser on the review, signed on as a litigation consultant for counsel suing Monsanto on behalf of alleged glyphosate cancer victims. He reportedly received $450 per hour.

California responded to the IARC review by ordering that all glyphosate products carry a cancer warning. On Feb. 26, 2018, a federal judge struck down the requirement, ruling it “inherently misleading … when apparently all other regulatory and governmental bodies have found the opposite.”

An airboat applicator treating invasive West Indian marsh grass on a Florida lake.  The most effective herbicides for this invasive plant are glyphosate and imazapyr.
An airboat applicator treating invasive West Indian marsh grass on a Florida lake.  The most effective herbicides for this invasive plant are glyphosate and imazapyr.
Stephen F. Enloe, University of Florida Agronomy Department/Center for Aquatic and Invasive Plants

When I inform people that glyphosate doesn’t cause cancer, I tend to get responses like: “OK, drink a glass.” I could, with impunity. It’s a plant poison that passes harmlessly through human digestive tracts. “LD50” stands for the lethal dose that kills half the test animals when given to them in doses per unit of body mass. Higher is safer. For rats, caffeine’s LD50 is 192 mg/kg.
Glyphosate’s is 5,600 mg/kg.

Yet, some environmental groups are calling for a total ban on glyphosate, and many are recycling the untruth that it’s carcinogenic. These include the Environmental Working Group, Center for Biological Diversity, Natural Resources Defense Council, EcoWatch, Greenpeace, U.S. Public Interest Research Group, Sierra Club, and Friends of the Earth.

That they hate Monsanto is understandable. Monsanto’s parent company, Bayer, produces and promotes truly dangerous products like neonicotinoid insecticides (which poison pollinators). Monsanto has also created genetically modified crops that are immune to Roundup and allow agribusiness to blitz entire plantations, weeds and all.* When Roundup (or any chemical) is overused like this there can be environmental damage.

“When you apply the same herbicide on 200 million acres multiple times a year, a few weeds are gonna get lucky and then pass on their resistance,” says Van Wychen.

These “super weeds” then require more dangerous herbicides like Monsanto’s Dicamba, which can drift long distances. In 2018, it killed crops on hundreds of Midwest farms. There’s also evidence that massive doses of glyphosate applied to ag land can limit amphibians and such insects as milkweed-dependent monarch butterflies.

And the blast-everything approach to ag-land weed management enabled by Monsanto’s GMOs has resulted in trace amounts of glyphosate showing up in cereal, wine and beer. They’re small amounts that don’t affect human health, but I don’t blame consumers for objecting.

“I get pissed off at Monsanto myself,” says Van Wychen. But none of this makes glyphosate a carcinogen.

Glyphosate treatment of phragmites infestation at Assateague Island National Seashore.
Glyphosate treatment of phragmites infestation at Assateague Island National Seashore.
Assateague Island National Seashore

Here’s why protecting the proper, responsible uses of glyphosate matters so much (and should matter to the very organizations that want the herbicide off the market): A total ban on all glyphosate use would be an unmitigated disaster for fish and wildlife. Glyphosate is the most effective tool, often the only tool, wildland and aquatic managers have for restoring fish and wildlife habitats destroyed by alien plants. Even when they spray glyphosate, they use minuscule amounts and frequently they merely inject it into individual plants or paint it onto cut stems.

“Sure, it’s always better to use no-toxic alternatives, if they’re practicable,” says Dan Ashe, who directed the U.S. Fish and Wildlife Service under Barack Obama. “Often, however, they’re simply not. For instance, it would have been possible to hand-pull the head-high invasive verbesina from the ground at Midway Atoll National Wildlife Refuge, but it would have taken time and personnel that were simply not available. Use of herbicides like Roundup can accelerate the work, creating urgently needed nesting space for thousands of albatrosses.”

One boots-on-the ground NGO that gets it about glyphosate is the Nature Conservancy (for whom, full disclosure, I contribute a column to its online magazine). It applies glyphosate more than any of the other 18 herbicides it uses to save and recover fish and wildlife.

In Augus,t I toured TNC’s floodplain-forest restoration project at the Silvio Conte National Wildlife Refuge along the Connecticut River in Massachusetts. Guiding me was TNC’s floodplain ecologist, Christian Marks.

Floodplain forests are endangered habitats. American elm, the oldest and most abundant floodplain species, has been devastated by Dutch elm disease. But TNC and its partners have developed disease-resistant elms. Marks and his team are planting these and other vanishing floodplain species in the refuge’s abandoned hayfields.

But first they must eradicate alien vegetation that would otherwise shade out seedlings. Their only option is glyphosate.

The results I saw were stunning and uplifting: fields bright with native forbs and wildflowers; bees, hummingbirds and butterflies nectaring on blooms; goldfinches gorging on thistle seed; kingbirds hawking insects. Inside deer-proof electric fences planted saplings thrived.

Floodplain trees produce seeds in spring, refueling countless species of birds exhausted from migration. That’s why migratory birds follow river corridors north.

Elms, highest in the floodplain, drop seeds first because that’s where the spring freshet first recedes, then silver maples, then cottonwoods, then willows, each feeding different bird species as they arrive.

Recently, representatives of an environmental group (Marks can’t remember which) knocked on his door, asking that he sign a petition to ban glyphosate on all public lands. “A ban would have blocked this restoration,” he told us.

America’s three coasts and inland lakes and rivers are blighted by phragmites, an alien grass. It’s crowding out native plants and evicting mammals, birds, reptiles, amphibians, fish, and invertebrates—which, given that surviving habitats are fully occupied, is often a death sentence.

In Utah, for example, phragmites has wiped out gamefish and waterfowl and pushed a federally endangered fish—the June sucker—closer to extinction.

Phragmites roots run so deep that it in most cases the only management option is herbicide, usually glyphosate.

Aaron Eagar, the state’s noxious-weed program manager, explains: “Utah Lake has 7,000 acres of phragmites around its shoreline. In the 1950s it wasn’t there. For the last seven years we’ve treated it with Rodeo [a glyphosate formulation labeled for water], and we’ve brought back lots of natives and opened up areas for fish and fishing.”

In the Everglades, Old World climbing fern smothers critical wildlife habitat called “tree islands,” evicting (therefore killing) raptors, ducks, wading birds, marsh rabbits, deer, raccoons, opossums, otters, reptiles and amphibians.

Wherever the South Florida Water Management District treats infested tree islands with glyphosate, it reports “amazing results, speedy resurgence of native ferns and forb-type understory plants.”

“We thought all the native canopy growth was dead,” says district invasive species biologist LeRoy Rodgers. “Though stressed and defoliated, species like dahoon holly, swamp bay, wax myrtle, coco plum and red maple are coming back.”

California verdicts notwithstanding, there’s zero evidence that glyphosate causes cancer or otherwise endangers the public. But bans on all glyphosate use are proliferating locally, and a national ban seems possible if not probable. The safety of herbicides needs to be determined by scientists, not chemophobic California jurors or vulturine attorneys. The health of our native ecosystems depends on it.

Update, Oct. 18, 2019: This article has been updated with information clarifying Christopher Portier’s role with regard to the IARC review.

Correction, Oct. 18, 2019, 11:20 a.m.: An earlier version of this article misstated that Monsanto makes neonicotinoids when it is Monsanto’s parent company, Bayer, that produces them.