Crop volunteers and climate change. Effects of future climate change on the occurrence of maize, sugar beet and potato volunteers in the Netherlands

COGEM has commissioned a research project on the effect of possible future climate change on the occurrence of volunteers of potato, corn and sugar beet, in order to allow a timely adjustment of COGEM’s advices if needed.

The researchers investigated whether the survivability of potato, corn and sugar beet could change as a result of possible future climate change. The climatic factors that are most important for survival of potato, corn and sugar beet, such as temperature, precipitation and soil moisture content were identified by reviewing the available scientific literature.  Subsequently, the four KNMI climate scenarios that describe the possible climate of the Netherlands in 2050 were used to estimate whether these climatic factors and hence the survivability of the above mentioned crops would change. The researchers concluded that it was not possible to predict the effect of the possible future climate change on the survivability of potato, corn and sugar beet, because it was not clear how some of the identified climatic factors would change.

In its advices on the environmental risk of GM crops, COGEM considers worst case scenarios. As a consequence, COGEM assumes that volunteers will occur, even if volunteers are observed rarely. COGEM is of the opinion that even if the climate would change there are no indications that feral populations of potato or corn would occur in the Netherlands. There are also no indications that sugar beet could form feral populations, but cross compatible relatives of sugar beet, i.e. weed beet and sea beet are already present in the Netherlands. The researchers consider the inland movement of sea beet or the formation of feral weed beet populations outside cultivated areas not likely. Although COGEM agrees with the researchers, COGEM will remain to take the presence of crossable wild relatives into account when it is asked to advice on the environmental risks of sugar beet. As a consequence, COGEM will consider whether outcrossing of transgenes into weed beets or sea beet could result in a risk to the environment.

COGEM concludes that it is unclear how the expected climate change will influence the survival of potato, sugar beet and corn. If changes will occur, these will occur over a period of time. COGEM is of the opinion that currently there is no reason to reconsider its previous risk analyses. If there is less uncertainty on the effect of possible future climate change on the survivability of the above mentioned crops, COGEM will take the effect into account in its risk assessments and will revise its previous risk assessments if this is considered necessary.