In a warming world, the weather will get wetter because warm air is able to hold more water. Consequently, when rains fall, it will be in torrents; while evaporation will be quicker and dryer. Geographic regions that are wet will become wetter. Regions that are dry will become drier. This makes agricultural planning difficult for farmers.
“Farmers know all too well that agriculture is highly dependent on weather. Modern methods, techniques, and technologies have made today’s crop and livestock farms increasingly productive, but agricultural success still depends on getting just the right amount of rain and just the right amount of heat at just the right time of year.
- The planting, maturing, and harvesting of crops all depend on consistent seasonal patterns.
- Livestock depend on feed, water, and a tolerable range of heat and humidity for healthy, productive growth.
- Climate helps determine which pests and diseases will spread, and so how much time, effort, and money farmers must spend on herbicides, insecticides, and other defences.
- Beyond the harvest, patterns of temperature and weather affect the entire supply chain of storage and transportation that brings food from the field to the dinner plate.
From the largest farm to the smallest market garden, from planting to eating, and at every stage in the cycle of production –from choosing seed to transporting livestock – agriculture and agri-business thoroughly depend on climate. And the climate is changing.1
Food Security And Nutrition
A changing climate “affects all dimensions of food security and nutrition:
- Food availability: Changes in climatic conditions have already affected the production of some staple crops, and future climate change threatens to exacerbate this. Higher temperatures will have an impact on yields while changes in rainfall could affect both crop quality and quantity.
- Food access: Climate change could increase the prices of major crops in some regions. For the most vulnerable people, lower agricultural output means lower incomes. Under these conditions, the poorest people — who already use most of their income on food — sacrifice additional income and other assets to meet their nutritional requirements, or resort to poor coping strategies.
- Food utilization: Climate-related risks affect calorie intake, particularly in areas where chronic food insecurity is already a significant problem. Changing climatic conditions could also create a vicious cycle of disease and hunger. Nutrition is likely to be affected by climate change through related impacts on food security, dietary diversity, care practices and health.
- Food stability: The climatic variability produced by more frequent and intense weather events can upset the stability of individuals’ and government food security strategies, creating fluctuations in food availability, access and utilization.” 2
Several reports by the UN intergovernmental panel on climate change (IPCC) “all point to climatic extremes as one of the major impacts of climate change” said Prof Riccardo Valentini, a director of the Euro-Mediterranean Center for climate change. Other factors affecting food security include:
Drought and aquifer depletion
Aquifers are fed by rain. The worst drought in San Joaquin Valley in central California caused farmers to drill wells and extract billions of gallons of groundwater, depleting a resource faster than it could be replenished. As a result of this massive depletion, the land is sinking as a result — by up to a half-meter annually according to a new Cornell University study in Science Advances.
Pest increase and invasion
“Dan Bebber, from University of Exeter, who led the research published in the journal Nature Climate Change, said: “If crop pests continue to march polewards as the Earth warms, the combined effects of a growing world population and the increased loss of crops to pests will pose a serious threat to global food security.” One example of a serious weather-sensitive pest was the mountain pine beetle, Denroctonus ponderosae. Warmer weather had driven the beetle northward to destroy large areas of pine forest in the US Pacific north-west. Another was rice blast fungus, a devastating pest affecting more than 80 countries which was now attacking wheat. Considered a new disease, “wheat blast” is having a severe impact in Brazil and there are fears of it spreading further north to the US. The scientists wrote: “Observed changes in pest distributions accord with observations of wild species, direct responses of pests to warming, and with expectations for expanding pest ranges under climate change.”3
In 2019 Italy will see a 57% plunge in its olive oil harvest. Olive oil infestations have hit farmers in both Italy and Greece. “The problem this year was because of fly attacks but also the gloeosporium olivarum fungus,” said Vasilis Pyrgiotis, the chair of the Copa Cogeca farming union’s olives working group. Italy sees a 57% drop in the olive oil harvest in 2019. Italy’s Coldiretti farmers’ union estimates that the cost of the olive oil collapse this year has already reached €1bn. Beyond Italy, the European commission has projected 2018-19 olive harvests to drop by 20% in Portugal and 42% in Greece, although industry sources said final figures there could be significantly worse.”4
Ocean Acidification
One of the scariest and potentially most dangerous effects of global warming is ocean acidification. Oceans absorb 30% of the earth’s carbon dioxide. Carbon pollution is changing the chemical makeup of the seas. Many marine species cannot survive in an increasing acidic environment. For example, increasing acidity weakens the shells of shellfish. Also researchers from MIT and the University of Alabama at Birmingham have found that increased ocean acidification will have a serious affect on global populations of phytoplankton — microorganisms on the ocean surface that make up the base of the marine food chain for other species that feed on them. Given that seafood is a large part of many people’s diets around the world, especially in low income, food deficit countries where seafood contributes approximately 20 percent of their animal protein.
Footnotes
1Agriculture and Climate Change, Climate Atlas of Canada
2Climate Impacts on Food Security, World Food Programme
3Climate change makes pests move north from the tropics – study; The Guardian; September 2nd 2013
4Italy sees 57% drop in olive oil harvest, The Guardian; March 5th 2019