Don’t panic, weedkiller has been helping, not hurting, us
SENSATIONALIST
headlines about glyphosate were plastered across media worldwide last week.
This followed a Brazilian court ruling to suspend the registration of glyphosate until a national health regulatory agency completes a toxicological re-evaluation.
Within days of that ruling, the Californian Superior Court ruled that Monsanto was liable in a lawsuit filed by a man who alleged the company’s glyphosate-based products caused his cancer.
Glyphosate is one of the
Jan Davis
world’s most widely used broad spectrum weedkillers. Commercial agriculture accounts for the bulk of global demand, with products based on glyphosate making up a quarter of herbicide sales. You’ll also find it in most garden sheds under the brand name Roundup.
The effectiveness of glyphosate as a weedkiller is unprecedented, especially since there are many much more powerful and toxic chemicals that have been approved for agricultural use.
Farmers reckon glyphosate is a good news story, because it has reduced the total volume of pesticides and herbicides needed to grow Roundupresistant crops. It has enabled minimum tillage production systems which have protected soil structure, improved soil moisture retention and increased soil carbon storage. It is one of the main reasons for increased yields of wheat, which have quadrupled in the last 50 years.
The use of glyphosate has long been challenged by environmental and health activists. In recent times, much of the opposition has been based on a report claiming to find evidence glyphosate is “probably carcinogenic”. Published in 2015 by the International Agency for Research on Cancer (IARC), part of the World Health Organisation, this report has since been discredited by experts.
No other herbicide has been subjected to as many rigorous investigations and there is no scientific proof it has harmed, let alone killed, anyone.
Some chemicals are highly toxic in very small doses. Glyphosate is not one of those. Its LD50 — the lethal dose for 50 per cent of rats in testing — is 5600 mg/kg. The LD50 for caffeine? 192 mg/kg — but I haven’t noticed a rush to ban that!
The US Agricultural Health Study is the world’s largest study of agricultural workers. It has been tracking 89,000 farmers who use glyphosate for 23 years. It has found “no association between glyphosate exposure and all cancer incidence or most of the specific cancer subtypes evaluated”.
There is clear evidence it has kept millions of people alive, because we’ve been able to sustainably produce more food and fibre from finite
resources of land and water.
A recent study concluded banning glyphosate would have significant effects on world wellbeing. There would be an annual loss of global farm income gains of US$6.76 billion; annual environmental loss associated with a net increase of 8.2 million kg of herbicide usage resulting from use of alternative products; additional carbon emissions from increased fuel usage and decreased soil carbon sequestration, equal to adding 11.77 million cars; and land use changes to meet demand for increased croplands would create an additional 234 million tonnes of CO2 emissions. It was estimated that global welfare would fall by US$7408 million per year.
A wide array of impressive experts has expressed dismay at the recent decisions.
Paul Pharoah, professor of Cancer Epidemiology at the University of Cambridge, said “the epidemiological evidence that glyphosates are associated with an increased risk of lymphoma is very weak … From a purely scientific point of view, I do not think that the judgment makes sense.”
We live in an age where science-based evidence struggles to stand against illinformed opinion; and the divide between those growing food and those eating it is stark. In this environment, it is all too easy to succumb to stereotypes. Farmers are often vilified as profit-hungry and careless, belittled as simple, and written off as stubborn. And many farmers assume those who live in the city are naive and hypocritical. There is no easy solution. It’ll take willingness on both sides to push past stereotypes in the hope that a stable relationship between consumers and those who grow their food is something worth striving for.
Instead of throwing fuel on the fires, we need to work on bridging that gap. We can start with taking a calm look at the science behind glyphosate and considering the whole picture, rather than responding with simplistic ill-informed kneejerk reactions.