A recent study has shown that the increase in CO2 levels globally will have a massive impact on the nutrients we obtain from crops.
Experiments have indicated that the levels of protein, iron and zinc will decline by up to 10% in rice and wheat by 2050. This could have serious health implications for billions of people around the world, particularly those in developing nations.
The researchers have experienced difficulty over the past 20 years in designing large scale field trials to allow accurate models of the impact of the increased CO2 levels on the nutrition levels of crops.
The data that has been used is based on experiments done in the US, Australia and Japan. They have been able to grow 41 different varieties of legumes and grains in open fields, with levels of CO2 which are expected around 2050.
The lead author of the study, Dr Samuel Myers, from Harvard School of Public Health, has stated that this is the most significant health threat linked to climate change. He said that they found huge protein, zinc and iron reductions in wheat and rice, as well as massive reductions in zinc and iron in field peas and soybeans.
Approximately one third of the world’s population is already suffering from zinc and iron deficiencies. This equates to around 63 million life years being lost on an annual basis as a result of the problem.
Dr Myers stated that almost two billion people are obtaining around 70% of their zinc and iron from these legumes and grains. This means that reductions in those particular crops are extremely worrying as regards an increase in deficiencies.
He stated that the problem cannot be overcome by consuming more food to make up for the variance. If you consume more calories each day, you would simply become obese over a period of a few months, which would increase the risk of metabolic illnesses.
The scientists are not sure what impact CO2 levels of 550 parts per million would have on crops. It was assumed that the crops would substitute carbohydrates for the nutrients as the gas was increased, but the results of the research were not consistent regarding this.
The researchers found that certain types of rice showed large differences in responding to the CO2 which offers hope for reductions in nutrients.
Dr Myers stated that this would allow a process where rice which is less sensitive to CO2 could be grown. He stated that they have not proven this possibility, but simply stating the possibility.
He stated that breeding programmes appear to be good on paper, but once the cultivar is produced, the yield may not be adequate, or it may not taste very good.
According to the Intergovernmental Panel on Climate Change, it is expected that crop yields will suffer because of increased temperatures. Their summary of the impact of global warming indicated that maize, rice and wheat production would decline during the remaining years of this century.
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