According to Benbrook (1), primary producers applied about 51.3 million kilograms of glyphosate worldwide in 1995.
However, the quantities of glyphosate used globally have increased rapidly with the ever-increasing adoption of Genetically Engineered – Herbicide Tolerant (GE-HT) crops, especially in the USA.

In 2014, global arable cropping land totaled about 1.4 billion hectares, with an estimated 747 million kilograms of glyphosate applied. So, this area and volume used equates to a potential average of about 0.53 kilogram of glyphosate per hectare, sprayed across all cropping land globally, what an incredible statistic.

Glyphosate, out of patent, now represents a low cost, broad spectrum weed killer that translocates through to the distal roots from a foliar application. It is less toxic than salt on an acute oral LD50 basis.

Given average rates of pesticides used in practice range from 1.5–2.0 kilogram/hectare, the total volume of glyphosate active applied in 2014 would have been sufficient to treat up to 30% of available cropped land that year.

No other pesticide comes even close to this sort of global success, but given every action has an equal and opposite reaction, are we considering the risks attached to the benefits of such global adoption of herbicidal weed control with the same mode of action? Just as medicines have side effects which may affect 0.1 to 1% of the population with an uncommon side effect classification, then it would be prudent to consider the cost to benefit analysis of such widespread glyphosate adoption worldwide.

Use of Glyphosate

Few would argue the benefits broad spectrum weed control of fallow land using glyphosate at a low cost (including fuel savings) has brought croppers. This is in terms of preserving both soil moisture and plant available nitrogen and improving gross margins, in fact for every $1 spent on herbicides there can be up to an 8-fold return on investment (See weedsmart.org ). In a dry continent like Australia it is thought that up to 1/2 of the topsoil of cultivated land has been lost in the last century or so due to erosion. Reference (2) puts yearly soil losses to erosion in Australia at between 5 and 10 tons/hectare/year, hence the widespread adoption of “No or Zero Till” using herbicides like glyphosate to try and mitigate these erosion losses.

One can’t ignore the benefits to amenity areas as well in terms of low cost weed control maintaining the aesthetics and functionality of public parks, ovals and amenity areas, private gardens, bushland, aquatic areas as well as roadsides. There is no doubt that to remove or diminish the use of glyphosate for weed control in Australia would significantly increase the cost of weed control. Just think of the difference between the costs of spraying aquatic weeds with aquatic use approved glyphosates versus using a mechanical harvester.

The Costs/Risks

Health Costs

Is There a Risk to Human Health?

  • In March 2015, the World Health Organization’s (WHO) International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic in humans” (category 2A) based on their investigative studies.
  • In November 2015, the EFSA published an updated assessment report on glyphosate, concluding that “the substance is unlikely to be genotoxic or pose a carcinogenic threat to humans”.
  • In May 2016, the Joint Food Agriculture Organization (FAO)/ World Health Organization (WHO) Meeting on Pesticide Residues (JMPR) concluded that “glyphosate is unlikely to pose a carcinogenic risk to humans from exposure through the diet”, even at doses as high as 2,000 milligram/kilogram body weight orally.
  • In September 2016, a systematic review found no support for a causal relationship between glyphosate exposure and the risk of non-Hodgkin’s Lymphoma (NHL) or of multiple myeloma (3).

So, in terms of chronic effects on human health, you would be better to focus on the risks of known carcinogens such as diesel exhaust, nicotine and the ethanol/acetaldehyde in alcoholic beverages than concern yourself with glyphosate, see