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Climate change to reduce grain yield, food safety in danger

25 January 20197 min reading

“If the Earth warms up by 2°C, the agricultural problems will be more severe, especially in the Sahel region, the Mediterranean, Central Europe, Amazon, and Western and Eastern Africa. Turkey is located in the Mediterranean basin, which is expected to be the most affected region by climate change. When considering the yield decrease given for the world, we should expect that the yield decrease will be 27 percent in wheat, 14.4 percent in rice and 33.3 percent in maize by the end of the century. We hope that states will understand the vital importance of the situation, take necessary measures and keep people away from the negative results.”

Prof. M. Levent Kurnaz Bogazici University Center for Climate Change and Policy Studies Physics Department kurnaz@boun.edu.tr.

There is no need to tell those dealing with agriculture and particularly farmers that climate change exists. Those who spend every day with nature are well aware of the reality that climate and environment have been changing. Relatively, decision makers are slower to give thought to this issue. In fact, it is very difficult to tell if many governments comprehended the significance of this issue whereas many people are aware of this change.

States decided that climate change is an important problem and should be prevented within the shortest time after the 1992 Rio Conference. This agreement is named as United Nations Framework Convention on Climate Change (UNFCCC). However, it is difficult to tell that states took a serious step so far. It is decided to keep climate change under two degrees during the 21st Conference of Parties gathered in Paris in December 2015. In fact, it is underlined to limit the warming with 1.5 degrees in order not to face with the negative effects of the climate change.

After the Paris Agreement, states acted to see benefits of limiting the warming with 1.5 degrees and harms the limitation will bring in case of failure when it is understood that the limitation will yield serious costs.

At the beginning of Oct. 2018, the Intergovernmental Panel on Climate Change – a United Nations body – announced its report about the limitation.

Climate change affects food and nutrition. This effect manifests itself through changes in the existence, quality, accessibility and distribution of food. In 2016, at least 815 million people, which mean 11 percent of the world population, faced with malnutrition, but the malnutrition has not equally distributed to the world. In parallel to the decline in food safety, the malnutrition has occurred more in Africa (20%), Southeast Asia (14.4%), and the Caribbean (17.7%). If the world gets warmer by 2°C instead of 1.5°C; food safety, nutrient content and nutrient’s yields, livestock, fisheries and aquaculture will worsen due to extreme weather events. It is estimated that it would be very difficult to carry out the UN Sustainable Development Targets, especially eradicating poverty and inequality, considering the effects of climate change on yield, arable field, pests, price, and food supply.

If 2°C global warming instead of 1,5°C occurs, it will create huge risks in crop yield and generally in nutrition all around the world and regions particularly places between 40 degrees north and south latitude. The rise of carbon dioxide in the atmosphere will increase the temperature and extreme weather events. That means there will be extreme rainfall during the hot and dry period. Thus, climate change may worsen the malnutrition and reduce the access to food and the quality of food product.

The decrease in water used for agriculture and drinking and the access to food based on water availability will be much less in 1.5°C compared to 2°C warming. If the Earth arms up by 2°C, the agricultural problems will be more severe especially in the Sahel region, the Mediterranean, Central Europe, Amazon, and Western and Eastern Africa.

Not all news is bad. Some studies have reported that the concentration of carbon dioxide in 2°C is more beneficial particularly in poles when compared to 1.5°C. In contrast to the lower latitudes, production at higher latitudes may benefit from an increase in agricultural areas and an increase in crops and pastures. A similar situation can be said for high-latitude fishing, which will also be affected by the melting of glaciers.

Theoretically, C3 plants such as wheat, rice and potatoes are expected to grow faster due to the increased CO2 content in the atmosphere, which has not been observed enough in the field. Moreover, loss of protein and nutrient content is frequently observed in plants raised under temperature stress. Additionally, some micronutrients, such as iron and zinc, will also accumulate less and be less in the produced food. When we examine all these effects together, it is estimated that protein deficiency will affect an additional 150 million people by 2050.

Factors affecting food safety projections include the changes in regional climate projections, studies to reduce climate change, biological reactions expected from agricultural products, extreme weather conditions (drought, flood), financial fluctuation and changes in the distribution of insects and illnesses. Changes in temperature and precipitation are expected to increase global food prices by 3-84 percent by 2050. The impact of climate change on food prices should be considered together with changes in land use, energy policies and food trade. In particular, the use of agricultural land for energy production and the development of this as a policy tool can further increase problems.

Although states focused on limiting the warming by 1.5 and 2 degrees, efforts so far shown by states since the Paris Conference indicated that they did not grasp the significance of the issue. Even if states realize the promises they have given, it is estimated that global warming would not be less than 3 degrees. Considering that the countries like the United States announced they would not adhere to their commitments, it is clear that global warming will be more than 3 degrees.

The studies conducted so far show that yield of all grains, especially wheat and maize, are falling after the 2-degree-threshold is exceeded. It has been reported that the temperature increase in tropics causes a half-ton reduction of yield per hectare in maize farming. Similar studies have shown that the yield decreases by 6.0 % for wheat, 3.2 % for rice, 7.4 % for maize, and 3.1 % for soybean for every degree of temperature increase.

Turkey is located in the Mediterranean basin, which is expected to be the most affected region by climate change. The temperature increase observed in the Mediterranean basin is 50 percent higher than the global average. That is, in case no precaution is taken if the world average will increase by 3 degrees by the end of the century, this increase will be at least 4.5 degrees in our country. The temperature increase will reduce the precipitation by 20-30 percent while the effect of this decrease will be more severe if the precipitation turns into a downpour. Thus, when considering the yield decrease given for the world, we should expect that the yield decrease will be 27 percent in wheat, 14.4 percent in rice, 33.3 percent in maize and 14 percent in soybean by the end of the century.

Climate change is expected to have extremely striking results, especially in the region where we live. We hope that states will understand the seriousness of the situation, take necessary measures, and keep people away from the negative results. However, we should plan for the worst scenario considering all possibilities.

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