Climate change, food production and food security


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Last week we introduced a study looking at how climate change will potentially affect crop growing in sub-Saharan Africa and how extreme the changes to farming methods will need to be in order to adapt. Now several recent articles researchers explain how food and nutrition insecurity is likely to worsen in the face of climate change and how we can prevent our food production systems from undermining efforts to mitigate the long-term climate effects.

A recent study in The Lancet, building on previous research, indicates that global food supply as impacted by climate change could cause over half a million deaths by 2050, largely due to a rise in undernutrition. While it is understood, at least to some degree, that crop yields will be affected, largely adversely, by climate change, the findings that it will also affect the composition of many people’s diets is relatively novel. The study also predicts the impacts of climate on diets will surpass undernutrition as a major cause of death.

The availability of healthy foods is expected to decline under climate change with consumption of fruits and vegetables predicted to decrease by some 4% by 2050, in comparison with a scenario free of global warming. And while this decline is likely to be most severe in low and medium-income countries in the Western Pacific region, the impacts will be felt everywhere including high-income countries.

And we are already seeing the effects of climate change in Southeast Asia and Africa where droughts have increased undernutrition in children, food prices have dramatically increased and crop production declined. Obviously since the poorest households spend the highest proportion of their income on food, low food availability and increased food prices will have a substantially greater impact on them. While meeting commitments made in the Paris Agreement will go some way to minimising the effects of climate change on diets and nutrition, governments will also need policies in place to address shortfalls in both production and in consumption.

A paper published in Nature recently showed that emissions from human activities such as food production are preventing the terrestrial biosphere from absorbing a large share of carbon dioxide emissions produced by humans. As such efforts to stabilise global warming below the agreed 2℃ are being undermined despite gains in reducing emissions from, for example, fossil fuels.

To further explain this effect, of the some 40 billion tonnes of CO2 emissions that are annually produced, largely from burning fossil fuels and deforestation, around 25% are absorbed and used by plants as they grow and another 25% is estimated to be soaked by the oceans. The remaining portion as we know remains in the atmosphere warming the planet. Climate change isn’t just about carbon dioxide, however. Nitrous oxide (N2O) and methane (CH4) are also greenhouse gases and are predominantly created through the food industry, from livestock, rice cultivation, manure, conversion of land to other uses, fertiliser use and landfills, for example.

While the land is at present a sink for CO2it is a source of methane and nitrous oxide, gases which actually have a greater warming potential than CO2. Data from the 2000s show that the combination of emissions from land use change, N2O and CH4, they equal the emissions from fossil fuel combustion. A large portion of this land use change is often associated with deforestation to make way for food production.

The study shows the importance of investigating all three of these main greenhouse gases to ensure actions to mitigate climate change are effective. The good news is that there are many options for reducing these emissions in the food production sector. Nitrogen fertiliser is notoriously overused, particularly since “only 17 of 100 units of nitrogen applied to the crop system ends up in the food we eat”. And yet little of the climate discussions centres on reducing emissions from agriculture, as opposed to the energy or transport sectors, perhaps because feeding people will always be a top priority. But since climate change is likely to exacerbate the huge task of feeding the world, mitigation needs to be a priority for every sector.

Now in a new book author Eric Toensmeier explores how carbon farming can be the solution to reducing greenhouse gas emissions from agriculture. The Carbon Farming Solution: A Global Toolkit of Perennial Crops and Regenerative Agriculture Practices for Climate Change Mitigation and Food Security, explores how carbon farming has “the potential to return the carbon dioxide in our atmosphere to the “magic number” of 350 parts per million, while feeding people, building more fertile soils, and contributing to ecosystem health”. An interview with the author explains why such climate-friendly farming methods are both widely used but also little discussed, how climate-smart farming may be a Trojan horse for business as usual and why we are on a deadline to transform agriculture. Although little mention of nitrous oxide and methane are given, the book and other discussions and articles make it clear that agriculture and food security are beginning to be put in the spotlight where climate change is concerned.


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