"It's been a very successful technology in many parts of the world. Ten per cent of the world's crops are now GM."
Professor Graham Jellis, Channel 4 News, 27 May 2012
Professor Jellis discussed genetically modified crops with Theo Simon on a Channel 4 News panel segment on Sunday evening. The panel came after a report into the weekend's anti-GM protests at Rothamstead.
To what extent is it fair to say that ten per cent of the world's crops are now genetically modified? Is there an accurate way of measuring the proportion of the world's crops which are genetically modified and, if so, is Professor Jellis' claim correct?
What figures can be found?
We've been in touch with Professor Jellis to enquire after his source for the claim, and look forward to hearing back from him.
The varying ways in which genetically modified crops are regulated in different parts of the globe means that it can be difficult to pin down a figure for the scale of GM crop cultivation worldwide.
The International Service for the Acquisition of Agri-Biotech Applications (ISAAA) is one body that can offer some insight. A special edition of its Crop Biotech Update, published on 22 February 2011, claimed that the GM industry had grown by 10 per cent in 2009/10:
"Growth remains strong, with biotech hectarage increasing 14 million hectares -- or 10 percent — between 2009 and 2010."
The proportion here is correct, but it's in relation to an increase in genetically modified crop hectarage between 2009 and 2010 — not the amount of crops which currently are genetically modified.
The ISAAA's most recent Global Status of Commercialised Biotech/GM Crops claims that there were 160 million hectares of genetically modified crops as of 2011.
The problem is that this report doesn't tell us what this number is in proportion to the total amount of crops grown in the world — we just know that 160 million hectares are being cultivated.
It's also worth bearing in mind that ISAAA methodology has previously been contested.
What can be done with what we have?
If we proceed on the basis that 160 million hectare figure is accurate we could gauge the accuracy of Professor Jellis's claim by showing it as a proportion of the world's total crops.
Unfortunately, finding a figure for the total area taken up by all crops is more complicated than it might sound. The Food and Agriculture Organisation of the United Nations (FAO) claims that the world's agricultural area, as of 2009, stood at roughly 4.9 billion hectares.
However it definition of agricultural area seems to go beyond the land used for crop growth, encompassing other uses such as pasture.
Agricultural area is therefore not an appropriate measurement to compare with the ISAAA's figure. Not everything which is grown or raised in an agricultural area will necessarily be crops, GM or otherwise.
The FAO does appear to have kept track of agricultural crop area for a time. Unfortunately, it doesn't seem to have done so since 2000 — its statistics hub currently only lets the user sort by 'agricultural area' as defined above, but not by 'crop area' or anything similar.
According to 'Extent of land use categories in the year 2000', the global hectarage stood at 15.3 million km² (1.53 billion hectares) in 2000.
Dividing 1.53 billion by 160 million comes to 9.58. In other words, if a similar amount of land was used for growing crops in 2011 as was in use in 2000, then it would be accurate to say that around 10 per cent of crops were GM (providing the ISAAA's figure is both correct and comparable).
Without Professor Jellis's input it is difficult to be certain about how the 10 per cent figure was arrived at.
According to the ISAAA, it is accurate to say that GM usage is growing by around 10 per cent year-on-year, but this doesn't give us any inkling as to the proportion of the world's crops that are already GM.
Our crude calculations certainly suggest that the proportion put forward may be in the right ballpark, but there are question marks about the reliability and comparability of the ISAAA and FAO datasets.
UPDATE: Professor Jellis has been in touch to let us know that he took his figure from the Food Standards Agency (FSA), which claims that "GM crops now occupy over 10% of the world's arable land". He has also told us that similar figures have been published elsewhere.
While the FSA page doesn't footnote individual claims, it does cite the ISAAA (among other things) as one of the resources it has used in this document. It's quite possible that the FSA reached the 10 per cent figure in a similar way to the above.
While there are still some question marks about how the details of the 10 per cent figure have been arrived at, Professor Jellis's claim is as well sourced as seems possible.
UPDATE 2: Reader Tony Woolf kindly wrote in to comment: I think the first question should be, what is meant by a percentage of crops? Percentage by land area does not seem at all an obvious meaning to me. Considering quantity of crops, I imagine the farmer would be interested mainly in the value, but weight might
also be a fair measure.
I imagine that GM crops give at least average yields, so if GM crops are grown on 10% of the world's agricultural area, I would think that the percentage of actual crops, however measured, could well be more than 10%.
(We are hoping to introduce comments on the site later this year. In the mean time, you can discuss articles on our facebook page)