The study, written by Dr Eric Davison, director of the Woods Hole Research Centre in Massachusetts, and published in the Institute of Physics (IOP) Publishing’s Environmental Research Letters, pointed out that the spreading of synthetic nitrogen fertilizers on soil and the storage of manure are major contributors of N20, which is the most potent greenhouse gas and the third biggest contributor to climate change behind carbon dioxide (CO2) and methane (CH4).
It said that in order to reduce emissions, there needs to be improved management of fertilizer and manure sources, as well as a 50% cut in per person consumption of meat across the developed world by 2050.
“N2O concentrations will continue to increase mostly unabated unless major improvements in agricultural efficiencies and/or significant changes in dietary habits of the developed world are achieved,” states the report.
The report considers the possibility of meeting the four scenarios, known as representative concentration pathways (RCPs), that the IPPC sets out in the draft of its Fifth Assessment Report. It concludes that three of the less aggressive scenarios could be met by reducing meat consumption, improving agricultural practices or reducing emissions. However, it states that in order to meet the most aggressive target of meeting stabilising N20 concentrations by 2050, there must be a 50% reduction in each of these areas.
Dr Davison acknowledged that achieving a 50% cut in meat consumption seems “unlikely under current trends”, but pointed out that large reductions in smoking have been achieved, suggesting that major changes in human behaviour are possible.
“If you had asked me 30 years ago if smoking would be banned in bars, I would have laughed and said that would be impossible in my lifetime, and yet it has come true,” he said. “Similarly, there would be beneficial health benefits for most Americans and western Europeans to stop ‘supersizing’ and rather to reduce portion sizes of red meat.”
In terms of fertiliser and manure management, the report states that technology is already available to reduce N20 emissions.
However, it adds “a lack of sufficient agricultural extension services, and the absence of political will for implementation remain major impediments to the adoption of technologies and practices.”
This analysis does not include any analysis on the impact of shifting meat consumption from beef to pork, poultry or fish, which have lower nitrogen footprints.