I'm trying to understand if glyphosate is carcinogenic. The information in internet is very confusing. There are many ecological oriented websites which claim it's carcinogenic which I suppose they could be biased, but also news websites stating that World Health Organization says "it's probably carcinogenic". In the other hand the European Union seems to sustain it's not, and it extended its license of use in a "heated debate". is it known if glyphosate is carcinogenic or not, or just there isn't enough evidence to sustain one thing or the other?
There is a difference between potential and risk. That's why different agencies came to different conclusions.
The IARC (International Agency for Research on Cancer, a body of the WHO) assesses the potential of a compound to cause cancer. They go through the research that point into this direction and if there is any hint that any dose of the compound might cause cancer they have to rate it accordingly. If you go through the IARC report on glyphosate, you find that a lot of the studies they looked into did not actually find a link between glyphosate and cancer in humans. Nevertheless, there are some studies that show that high doses of glyphosate can result in cancer in animals. So, the IARC had to conclude that glyphosate has the potential to cause cancer. They put it into the category 2A (probable carcinogens). In the same category you find red meat, hot beverages and being a hairdresser, because these things have the potential of causing cancer.
Agencies like the FDA, EFSA etc. are assessing the risk of cancer from "normal" glyphosate exposure. While it seems to be possible to get cancer from "too much" glyphosate, we are only exposed to a tiny fraction of that dose. While it's unavoidable that small amounts of glyphosate residues are found in our food, these amounts are most probably not harmful. At least, that's what most research concludes. The dose makes the poison. While eating fresh organic berries does not pose any risk to harm you, they naturally contain small quantities of chemicals that have the potential to harm you at high concentrations. Your body itself makes small amounts of compounds that have the potential to harm you (e.g. Formaldehyde).
That's why the debate is so heated. Environmental activists are taking the cancer potential assessment of the IARC and turn it into a risk for the consumer, which is untrue. If they would work with the same energy against other group 2A carcinogens, we would have to close down barber shops...
The research on Glyphosate and cancer is ambiguous however the journal Nature published a paper on January 9, 2017 that found that rats fed ultra-low doses of glyphosate developed non-alcoholic fatty liver disease. The article is: Multiomics reveal non-alcoholic fatty liver disease in rats following chronic exposure to an ultra-low dose of Roundup herbicide