Food waste accounts for a tenth of global greenhouse gas emissions

Around 1.3 bn tonnes of food is wasted annually and is expected to increase.

Cutting down food waste could help avoid a tenth of greenhouse gas emissions arising from agriculture, says a study from Potsdam Institute for Climate Impact Research. Agriculture accounted for more than 20 percent of overall global greenhouse-gas emissions in 2010.

Emissions from agriculture alone are expected to rise by up to 18 gigatonnes of CO2equivalents by 2050, previous research has shown. The Potsdam study shows changing lifestyles could see emissions associated with food waste increase tremendously from 0.5 to 1.9-2.5 gigatonnes of CO2 equivalents per year by 2050. Up to 14 percent of overall agricultural emissions in 2050 could easily be avoided by a better management of food utilisation and distribution, the authors said.

One-third of global food production ends up being wasted and this is expected to increase even more with China and India adopting western food patterns. Around 1.3 billion tonnes of food is wasted annually today, and most of this is in the rich countries.

While the global average food demand per person remained almost constant, in the last five decades, food availability has rapidly increased. "More importantly, food availability and requirement ratio show a linear relationship with human development, indicating that richer countries consume more food than is healthy or simply waste it," co-author Prajal Pradhan said.

The team from Potsdam Institute provides comprehensive food loss projections for countries around the world while also calculating the associated emissions. The researchers looked at body types and food requirements for the past and different future scenarios, considering growing population numbers, food demand and availability and associated emissions.

"Reducing food waste can contribute to fighting hunger, but to some extent also prevent climate impacts like more intense weather extremes and sea-level rise," lead author Ceren Hic says, noting that some developing countries still have to fight undernourishment or hunger.

As developing economies like China or India are projected to rapidly increase their food waste due to changing lifestyle, increasing welfare and consumption of more animal-based products, this could trigger large increase in greenhouse-gas emissions associated with food waste, said Jürgen Kropp, co-author and deputy chair of PIK research domain Climate Impacts and Vulnerabilities.

Emissions continue
The Paris Climate Agreement to limit warming to well below 2 degrees above pre-industrial levels however leaves a lot of leeway for the contributing countries, in terms of when to exactly start the emission reductions. While the aim is to cut net emissions to zero in the second half of this century, this may not be achieved unless reductions start now and are considerable, say scientists from the Oeschger Centre for Climate Change Research of the University of Bern.

As long as emissions continue to increase, future peak warming increases much faster than observed warming, namely 3 to 7.5 times as fast due to the inertia of the Climate System and the long atmospheric lifetime of CO2.

Delaying emission reductions by 10 years causes an additional increase in peak warming of 0.3 to 0.7°C, they said.

The United Nations Intergovernmental Panel on Climate Change projections of a scenario with no emission reductions sees temperatures rising by about 3.7 degrees Celsius by the end of the century.