The conversion of crops to meat is not particularly efficient (in the case of cattle, for example, about 30 pounds of feed are needed to grow a single pound of beef), so as global demand for meat rises, cropland devoted to growing animal feed will have to increase proportionately’. The latest of many is many studies to show the heavy meat based diet is bad for human and planet health is Global Diets Link Environmental Sustainability and Human Health by David Tilman & Michael Clark Nature Nov 2014. They say that ‘In particular, if the world were to adopt variations on three common diets, health would be greatly increased at the same time global GHGs were reduced by an amount equal to the current GHGs of all cars, trucks, planes, trains and ships. In addition, this dietary shift would prevent the destruction of an area of tropical forests of an area half as large as the United States’. The study projects that if the global rapid trend away from a plant based to a meat based diet continues by 2050 it will be responsible for an 80% in GHG emissions.

‘The maps showwhich regions produce crops that are mostly consumed directly by humans (in green), which regions produce about the same amount of human food and animal feed (in orange), and where most of the crops are used as animal feed (in red).

Meat

Peter Carter

Deforestation mainly for livestock pasture = 15 % CO2 emissions

The consumption of meat is rapidly increasing and meat production is currently responsible in total for 35% of anthropogenic greenhouse gas (GHG) emissions. The largest share of GHG emissions related to agriculture is from methane and nitrous oxide (UNEP Alert 2012). An FAO study found that the meat livestock world food supply is the direct and indirect source of half of all GHG emissions in CO2 equivalent

Methane has over 80 times the warming effect of CO2 for 20 year after emissions (global warming potential GWP) Nitrous oxide has over 250 times the effect of CO2.

World meat supply

Meat supply

Population

Methane molecules have over 80 times the warming effect of CO2 for 20 year after emissions (global warming potential GWP) Nitrous oxide has over 250 times the effect of CO2.

Greenhouse gas molecules by GWP

Methane >80 X CO2

Carbon dioxide

Nitrous oxide >250 X CO2

Actual difference is much greater than this illustration

The Global temperature cannot be stabilized without getting off the meat based diet