Global Warming Made Worse by Human Eating Habits, Shows Study

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In recent years reports on global warming have shifted away from firmly establishing a human connection to the phenomenon and have instead begun warning of the dire consequences humanity might face as a result of climate change. An Intergovernmental Panel on Climate Change (IPCC) assessment report released in April of this year warned that humans are "ill-prepared" for climate change and that more proactive steps will be needed to stop it. Now, a new study is showing that even the most ambitious plans to combat climate change might fail if humans don't change the way they eat.

The study, published in the journal Nature Climate Change, suggests that current human food production trends on their own could hit or exceed global greenhouse gas emissions targets by the year 2050. By that time, global cropland is predicted to have expanded by 42 percent, fertilizer use is expected to have increased by 45 percent, and one-tenth of the world's tropical forests might be gone.

The study's authors believe these changes will have to occur as a consequence of how humans are beginning to eat. As more people around the world begin to demand meat-heavy diets, agricultural production will have to ramp up to keep pace. This means more land will have to be cleared to feed a projected human population of 9.6 billion people in 2050. If changes aren't made, the study suggests that a combination of deforestation, livestock methane emissions, and fertilizer use will raise global greenhouse gas emissions from food production by around 80 percent by that time.

"There are basic laws of biophysics that we cannot evade," said Bojana Bajzelj lead author of the study and an engineering researcher at the University of Cambridge. "The average efficiency of livestock converting plant feed to meat is less than 3%, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals that provide meat for humans. The losses at each stage are large, and as humans globally eat more and more meat, conversion from plants to food becomes less and less efficient, driving agricultural expansion and land cover conversion, and releasing more greenhouse gases. Agricultural practices are not necessarily at fault here - but our choice of food is,"

Bajzelj and her colleagues suggest that food consumption habits will need to change drastically for this scenario to change. The researchers wrote that an "average balanced diet," if adopted throughout the world, could significantly reduce the impact of food production on climate change. The diet they suggest includes two small portions of red meat and five eggs per week, as well as a small portion of chicken every day.

"This is not a radical vegetarian argument; it is an argument about eating meat in sensible amounts as part of healthy, balanced diets," said Keith Richards, a co-author of the study and a professor of geography at Cambridge. "Managing the demand better, for example by focusing on health education, would bring double benefits - maintaining healthy populations, and greatly reducing critical pressures on the environment."