The great virtue of glyphosate, the world’s ‘favourite’ herbicide, is that it kills slowly and thoroughly; it disrupts amino acid synthesis in every cell, leading to plant death two weeks later. After converting to organic farming in the 1980s I missed it, but over the years we have found alternatives in stale seed beds, cultivation techniques, and thermal and inter-row weeding. Today, we generally control weeds effectively yet add only around 5% to our production costs.
48 MEPs recently tested 100% positive for glyphosate, with concentrations in their urine at 5-40 times the level considered acceptable in drinking water. The World Health Organisation has classified the chemical as a ‘probable carcinogen’ so, with the licence to sell and use glyphosate in Europe expiring this month, an argument is raging in Brussels over whether it should be renewed, and if so, under what terms. The evidence on either side is far from convincing but, predictably, the UK is for renewal. One would hope that a decision will be made based on an assessment of risks, rationally balanced against an assessment of benefits; but history (asbestos, DDT, dioxins, tobacco) suggests that we frequently underestimate risks stemming from what we just don’t know. The majority of pesticides I used as a teenager, judged safe at the time by our regulators (largely based on science selected and paid for by the manufacturers), have subsequently been banned on health or environmental grounds, often after long wrangles like the one going on in Brussels right now.
PCBs, another Monsanto product, were judged too toxic for use by the US Navy in the 1950s but it took another 20 years for them to be banned. Today every one of us carries these hormone-disrupting carcinogens in our bodies. One study suggests they reduce polar bear reproduction by weakening their penises; no-one predicted that consequence and I don’t suppose Monsanto will offer compensation. My point? When approving novel chemicals we need to consider what we don’t know we don’t know (Donald Rumsfeld’s “unknown unknowns”), what we know we don’t know (“known unknowns”), as well as what we know. This requires both caution and humility; rare qualities in those with political and economic power.