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Report doubles impact of farming’s contribution to greenhouse gases

A new global study on the impact of food production on climate change may help attitude changes in the important British market for New Zealand.

Nevil Gibson
Wed, 11 Jul 2018

A new global study on the impact of food production on climate change may help attitude changes in the important British market for New Zealand.

The report, Climate Change and Food Systems, released last week in Oslo, estimated food production was responsible for between 19% and 29% of mankind’s total greenhouse emissions, far above previous United Nations estimates of 14%, based on a narrower definition of farming.

Looking at emissions across the food system – including forest clearance, fertiliser production and transport, rather than just farming itself – the agriculture research organisation CGIAR says much more work is needed to cut climate change emissions from food.

“From a food point of view [the UN approach] doesn’t make sense,” says Bruce Campbell, who heads the CGIAR (Consultative Group on International Agricultural Research) research programme on climate change, agriculture and food security.

Many countries could make big cost savings by cutting emissions, he says.

“There are good economic reasons to improve efficiency in agriculture, not just to cut greenhouse gas emissions.”

China, for instance, could sharply reduce emissions with more efficient manufacture of fertilisers, while the UK could cut them by consuming lamb transported from more efficient farms in New Zealand rather than raising its own sheep.

This part of the report was picked by the Mail Online, Britain's most-read news website, and subsequently reported by the New Zealand media with appropriate local reaction.

Global changes in diet, shifting towards vegetarianism from meat, will also help, CGIAR says. Growing crops to feed to cows, pigs or sheep takes up far more land and emits more greenhouse gases than producing crops for human consumption.

A separate report by the CGIAR climate programme indicates climate change is likely to reduce yields of the three biggest crops judged by calorie production – maize, wheat and rice – in developing nations in coming decades.

That could force some farmers to make radical shifts to growing more heat-, flood- or drought-tolerant crops, according to the report, Recalibrating Food Production in the Developing World.

More resilient crops including yam, barley, cowpea, millet, lentils, cassava and bananas could fill in the gaps caused by declining harvests of more sensitive crops, it says.

“The world’s agricultural systems face an uphill struggle in feeding a projected 9-10 billion people by 2050. Climate change introduces a significant hurdle in this struggle.” The world population is now just above seven billion.

The study also says that global warming, blamed by a UN panel of climate experts mainly on the burning of fossil fuels, means risks to food production far beyond fields.

“Every step of the food chain – from the seed to the farm to the cooking pot – is at risk,” it says.

Higher temperatures or floods could make it harder to store and transport food, for instance, meaning more outbreaks of food-borne illnesses.

“Food-related emissions and the impacts of climate change on agriculture and the food system will profoundly alter the way we grow and produce food,” says Sonja Vermeulen, lead author of the second report.

“This will affect different parts of the world in radically different ways, but all regions will have to change their current approach to what they grow and eat.”

Climate change may cause irrigated wheat and rice yields in developing countries to fall by more than 10% by 2050, the study says, while feeding livestock with grain will become more expensive.

Nevil Gibson
Wed, 11 Jul 2018
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Report doubles impact of farming’s contribution to greenhouse gases