When we talk about the effects of climate change on agriculture, we think above all of droughts, heat waves and extreme weather events that can compromise harvests. But there is another, less obvious aspect, which directly concerns the quality of food: the increase in the concentration of carbon dioxide in the atmosphere can in fact also change the characteristics of the crops from which we obtain our food.
According to data reported by researchers at Leibniz Institute for Food Systems Biology of the Technical University of Munichglobal CO₂ concentrations have risen from around 340 parts per million (ppm) in 1980 to around 425 ppm in 2024. If emissions continue to rise, it could reach around 600 ppm by 2050.
And wheat, one of the most important food crops in the world, will therefore have to adapt to atmospheric conditions different from the current ones. But what happens to its characteristics when it grows in an environment with more carbon dioxide?
To investigate this question further, an international group of researchers analyzed ten varieties of winter wheat grown under field conditions. Part of the plants were exposed to a CO₂ concentration of 546 ppm, while the others grew with a concentration of around 450 ppm, corresponding to the reference environmental conditions used in the experiment.
After harvest, scientists examined the protein composition of the grains through high-precision laboratory analysis techniques, focusing in particular on gluten proteins, pureindolines and amylase/trypsin inhibitors, as well as some peptides involved in the immune response associated with celiac disease.
Less gluten protein and lower baking quality
One of the most significant results concerns gluten, the set of proteins that contributes to giving elasticity and structure to the dough, allowing the bread to develop during leavening.
In the presence of a higher concentration of CO₂, the quantity of the 21 gluten proteins analyzed decreased on average by 18.7%. The overall protein content of the beans was also lower, with an average reduction of 4.7%.
These changes did not just remain on paper. The bread-making tests highlighted a lower quality of the dough: the volume of the bread decreased on average by 4.1%, while the sedimentation volume, a parameter used to evaluate the technological quality of wheat proteins, decreased by 11.7%.
In other words, a higher concentration of CO₂ could make it more difficult to obtain flours with the same baking characteristics we are used to. It does not mean that all bread produced in the future will necessarily be worse, but that the composition of the starting grain could change, with consequences on its technological properties.
Some proteins associated with wheat sensitivity increase
The research also identified another variation that deserves attention. With higher levels of carbon dioxide, amylase/trypsin inhibitors, known by the acronym ATI, increased by an average of 5.7%.
These are proteins that wheat naturally produces as a defense mechanism against organisms that feed on the plant. However, they are also being studied for their possible involvement in wheat allergies and non-celiac wheat sensitivity, a condition in which some people report complaints after consuming foods containing wheat, without having a diagnosis of celiac disease.
The scientists also observed a decrease in pureindolines, proteins that contribute to determining the hardness of the grain and influence the processing characteristics of the flour.
The picture, therefore, is rather complex: the increase in CO₂ does not modify all the proteins in the same direction, but determines a different composition of the grain, with possible repercussions both on the technological characteristics and on those linked to the tolerability of the wheat.
What changes for those suffering from celiac disease? Among the most interesting aspects of the study there is also the decrease in some peptides active in celiac disease. These are short protein fragments that can form during the digestion of gluten and which, in genetically predisposed people, can activate the immune response responsible for the disease.
Their concentration was lower in samples grown with more CO₂. However, it would be wrong to interpret this data as a demonstration that the wheat of the future will be more suitable for people with celiac disease or that it can be consumed without risk by those who must avoid gluten.
In fact, the research analyzed only some of these peptides and did not carry out immunological tests or experiments on people. Furthermore, amylase/trypsin inhibitors, potentially involved in other disorders related to wheat consumption, increased in the same experiment.
As Katharina Scherf, head of the research group on the chemistry of food biopolymers at the Leibniz Institute, points out, the changes observed could also have relevance for diseases associated with wheat consumption, but further studies will be necessary to understand their real biological and immunological significance.
Not all varieties of wheat react the same way
There is another important element that emerged from the experimentation: the response to the increase in CO₂ depends greatly on the cultivated variety. In fact, the ten varieties analyzed did not all react in the same way. In nine of them the overall protein content of the grain decreased, with variations between 1.9% and 10.3%. One variety, Hyvega, showed an increase of 2.7%.
Even considering other protein characteristics, some varieties proved more sensitive to the new conditions than others. Apostel and KWS Emerick, for example, showed a relatively more stable response, while Asory, Campesino, LG Initial and Moschus showed more marked changes.
These differences could become important for the future of agriculture. According to the researchers, in fact, the selection of the varieties to be cultivated should not only aim to obtain abundant harvests, but also to preserve important qualitative characteristics, such as a good protein composition and high baking quality.
The wheat of the future
The research adds a piece to the understanding of the effects of climate change on our diet. It is not enough to ask how much wheat we will be able to produce in an atmosphere increasingly rich in CO₂, we will also have to understand what the quality of what we will bring to the table will be.
Of course, the results should be interpreted with caution. The experimentation was conducted in a single site and during a single growing season: further tests will therefore be needed, in different places and climatic conditions, to verify whether the same variations will recur on a large scale.
The message that emerges is nevertheless important: adapting agriculture to the climate crisis also means selecting crops capable of maintaining good nutritional and technological characteristics in the new environmental conditions. Because the future of wheat will not only be measured in tons collected, but also in the quality of the flour and bread that we will be able to obtain.
Sources: Leibniz Institute for Food Systems Biology / PubMed
