By: Alanna Shaikh, MPH on December 09, 2015Climate change is going to have a massive impact on food and food security. It’s both true and intuitive. Agriculture is a complex system that is also extremely climate-dependent. A new report from the United States Department of Agriculture seeks to identify those effects on the US and on the global food system.The conclusions are grim.Climate change is expected to disrupt food availability, decrease access to food, and make food utilization more difficult. Poor people and poor countries, especially those in tropical areas, will suffer most. This is not an exaggerated or alarmist conclusion; the report was developed by a wide consensus of academics, non-governmental organizations, and governments in four countries. It’s the closest we’re likely to come to a mainstream, conservative, view of the impact of climate change on food.That is not to say it is impossible to adapt to the new climate conditions. In some cases, in fact, it is relatively easy. Farmers can grow different varieties of crops, or even change crops entirely. They can learn to irrigate, or irrigate more effectively. There are a lot of simple innovations already available to help increase field productivity, even in a difficult climate.However, field crops are just one part of the global food system. Livestock is more of a challenge. A herd of cows, camels, or sheep is a capital investment. It is not easily harvested and switched out to something hardier. Hardier animals may also be less productive. The cows that give the most milk, for example, also need intensive protection and care. US farmers achieve tremendous milk production; they also build air-conditioned dairy barns.We then have to consider the non-agriculture aspects of the global food system. That includes factors like the price of oil and the impact of extreme weather events on roads, railways, and oceans. Hurricanes will affect the container ships carrying grain. Blizzards affect trains and trucking.The costs of storing and processing food will increase as the weather grows warmer and more extreme. One example: fungal contamination will be an increased risk in a warmer climate, leading to increased production of poisonous, nutrition-destroying mycotoxins. Warmer temperatures will also mean an increased spread of foodborne bacteria and viruses, as it gets more difficult to store food at safe temperatures. Electric grids will strain to keep up with the need for refrigeration.Because the global food system is so complex, some of the most interesting points in the report are in throwaway sentences. On page 87, it points out that “The nutritional quality of a number of staple foods is diminished by elevated atmospheric CO2 concentrations.” That will mean nutrient deficiencies. Page 101 mentions that we may see a shift to more consumption of highly processed foods because those foods are more stable than whole foods at a range of temperatures. Both of those changes will have major follow-on health impacts.Finally, report is focused on food security, so it doesn’t address one major point that I think must be mentioned. Small farmers, processors, and retailers are in trouble. They have less money and fewer resources to adapt to climate change. Small farmers are less likely to know about new crop varieties, or may not know how to sow and harvest them. Or, as the report puts it, “Yield gaps are typically caused by lack of access to contemporary technology and management knowledge.” The actors best able to adapt to climate change are agribusinesses, not subsistence farmers. Drying fruit in the sun is more difficult in unpredictable weather; the processor with a warehouse can rapidly outcompete anyone doing it outdoors. By the same logic, supermarkets can keep food cool – and safe – in a way that outdoor markets cannot.The future of the food system looks very corporate.