Food security


Food security

Ripening barley Hordeum vulgare © Ita McCobb

Anyone that takes regular walks or is involved in gardening of any kind will be only too aware that our climate is definitely changing.

At those times when we would usually expect to have sufficient proportions of rainfall and sunshine to enable plants to grow, flower and produce their fruits or seeds we are getting longer and heavier bouts of rainfall, dryer and more prolonged bouts of sunshine and powerful winds.

Plants are often outgrowing their normal height levels and can be seen shrivelling through lack of strength in extreme sunshine or being uprooted from scorched land by very strong winds or flooding. This has an effect not only on our own gardens and terraces but on world economies, an effect that can be and often is catastrophic.

Nature is a balance of elements between plant and plant, plants and insects, plants and animals, plants and mankind, insects and animals, animals and mankind and so on and so on. So any imbalance soon affects the whole.

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Extreme weather & crops


Of course the biggest climate change problem for the world is what the IPPC (Intergovernmental Panel on Climate Change) terms “Food security”. And as we have already seen in “Grasses as food”, grasses provide the main source of staple foodstuffs globally.

According to a study by researchers at the University of British Columbia and McGill University published in Nature in January 2016, drought and extreme heat cut cereal harvests by 9 to 10% on average in affected countries between 1964 and 2007.

Senior author Navin Ramankutty said, “Our findings may help guide agricultural priorities and adaptation efforts, to better protect the most vulnerable farming systems and the populations that depend on them.”

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Global food security

Wheat CWR Aegilops tauschii © School of Biosciences, Birmingham University

As the IPPC states in its “Fifth Assessment Report”, “Climate change multiplies the risks of natural hazards, through altered rainfall and temperature patterns as well as increased frequency and intensity of extreme events such as drought and flooding. Climate change is already having a negative impact on agriculture, affecting major crops, livestock production and fisheries. Those tropical areas of high exposure to climate change are also characterized by high food insecurity.”

The Climate Change Food Security Organization says, “Ozone in our air is toxic to our health and it is also toxic to green plants impairing their capacity to grow by photosynthesis”.

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C3 & C4 crops

They also comment that whereas higher CO2 levels are beneficial for many crops. In species with a C3 photosynthetic pathway, such as Rice and Wheat, higher CO2 directly stimulates photosynthetic rates, but this mechanism does not affect C4 crops like Maize.

The IPPC document confirms this, “For C3 crops, the negative effects of warming are often balanced by positive CO2 effects up to 2-3 °C local warming in temperate regions, after which negative warming effects dominate. Because temperate land areas will warm faster than the global average, this corresponds to roughly 1.25-2 °C in global average temperature.

“For C4 crops, even modest amounts of warming are detrimental in major growing regions given the small response to CO2. C4 crops are essential to world food security as they include Maize, Millet, Sorghum, Sugar cane and many pasture Grasses.”

A study that indicates this CO2 benefit is not working in reality is “Climate Trends and Global Crop Production Since 1980” by Lobell and Schlenker of Stanford University who found that farmers have produced less food during the past three decades than they would have done were climate change not happening.

Global Maize (corn) production is estimated to be about 3.8% less than it would have been in a non-warmed world. The study also points out that the United States, which produces about 40% of the world’s Soya and Maize, has so far been shielded from yield declines.

“There has been a perception that a perfect storm of conditions led to higher food prices in recent years. But that wasn’t the case at all, because this major producer wasn’t being detrimentally affected,” commented Lobell. “The US may have been lulled into a sense of complacency.”

The study also shows that temperature has had a much greater effect on crop yields than rainfall levels, so suggesting that heat-tolerant crop species may be more important than drought-resistant crop species.

They estimate that the negative effect of climate change on plant growth has cut wheat production by 2.5%, but boosted that of rice by 2.9% and soya beans by 1.3%. It has also increased food commodity prices worldwide by about 6.4% over 30 years.

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European food security

Wheat fields & Corn (Maize field) © A Willstrop

In 2014-15 the European Union led the world in Wheat production and exports. But Europe is also the region where productivity has slowed the most.

Frances C. Moore and Lobell made another study on “The fingerprint of climate trends on European crop yields” looking at two factors: actual crop yields and expected crop yields given historic temperature and precipitation trends.

Moore concluded that climate change can explain 10% of the slowdown in European Wheat and Barley yields, with changes in government policy and agriculture responsible for the remainder. She also found evidence that long-term temperature and precipitation trends since 1989 reduced European yields of wheat by 2.5% and barley by 3.8%, while slightly increasing that of maize and sugar beet yields.

It seems that due to climate change effects we should seriously consider changing our dietary habits while also expecting to pay more for our staple foods!

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References: Intergovernmental Panel on Climate Change (IPPC); United Nations Environment Programme (UNEP), Division of Technology, Industry and Economics;; Climate Trends and Global Crop Production Since 1980, Lobell, D. B., Schlenker, W. & Costa-Roberts, J., Science, doi:10.1126/science.1204531 (2011); The fingerprint of climate trends on European crop yields, Frances C. Moore and David B. Lobell, content/112/9/2670; Oxford English Dictionary, Oxford University Press.