In general, domestic meat has a larger carbon footprint than plant protein sources.
Livestock requires land to be designated for their feed. For example, to produce 1 kg of beef requires 5 – 7 kg of grain. This grain could otherwise be designated for human consumption or left as forested land.
In comparison, plant protein, such as legumes, can be immediately processed for human consumption.
Livestock production accounts for 70% of global agricultural land use. Due to growing agricultural demand, deforestation is a major concern, especially as trees are essential in removing carbon dioxide. Additionally, livestock contribute 18% of global GHGs, mainly in the form of methane and nitrous oxide.
There are many different diets that aim to reduce meat consumption. No one diet can be considered the be all end all. Both meat-based and plant-based diets produce significant amounts of GHGs, use substantial amounts of water, and require large areas of low carbon sequestering land (4).
The following chart shows some data collected from real people that self-selected their diets. While it provides a great idea of the approximate amount of GHGs that are generated, these numbers would certainly change from person to person. As well, these numbers do not include food waste. Studies have found that fruit and vegetables make up a higher proportion of food waste than meat.
|Diet||kgCO2e per day||kgCO2e per year|
|High meat eaters (>100g per day)||7.2||2,624|
|Medium meat eaters (50-99g per day)||5.6||2,055|
|Low meat eaters (<50g per day)||4.7||1,705|
Data source: Environmental Working Group (EWG)’s 2011 Meat Eater’s Guide, found here.
Solution 1: Cutting back on meat
Cutting back on meat once or twice per week makes a big difference.
Switching from a high to low meat diet would result in a reduction of almost 1 tonne of GHG emissions (919.8 kgCO2e per person per year)! (A family running a 10 year old small family car for 9,560 km has a carbon footprint of 2,440 kgCO2e.)
The following chart provides insight into the carbon and water intensity of different protein sources.
|Protein Source||kgCO2e per pound||Car km equivalent||Water footprint (litre per kg)|
|Dry Beans & Tofu||2.0||7||NA|
Data Source: Green Eatz
Source: Environmental Working Group (EWG)’s 2011 Meat Eater’s Guide, found here.
Solution 2: Beans for Beef
Methane is a major greenhouse gas that is emitted from livestock, particularly cows. Beef production alone is responsible for 37% of the human-related methane released. Plus, methane is 25 times more powerful than carbon dioxide.
If cutting out all meat is unrealistic, reducing beef consumption can make a huge impact. As seen in the above chart, beef generates 27 kgCO2e per pound, whereas dry beans only creates 2 kgCO2e per pound.
The following chart provides the nutritional benefits between these two protein sources to demonstrate that the additional inputs that go into livestock do not translate into additional nutrition for human consumption.
|5-ounce steak||1 cup (5 ounces) pinto beans|
|Fat (g)||12 (saturated)||1 (polyunsaturated)|
Nutritional Differences: 5 ounce steak vs. 1 cup (5 ounces) of pinto beans, data sourced from here.
Case Study: Fish
While fish may have a lower carbon footprint than ruminants, there are serious concerns with the sustainability of the fishing industry.
Approximately 90% of global fish stocks are either fully fished or overfished (read more here). Many fishing and farming methods result in habitat damage and by-catch – in which unintended fish species are picked up and not used. The result is serious ecosystem damage. Unsustainable fishing methods are making it more difficult to support the growing demand for fish as a protein source.
Human-driven climate change is also impacting the availability of fish species. Without proper GHG reductions and improved fishing management, there may become an even greater demand for protein sources that are more carbon-intensive than fish.
Solution: If choosing fish, follow the Ocean Wise seafood recommendations chart, found here. It is a comprehensive guide to “sustainable” and “not-recommended” species. Alternatively, buy or fish local Manitoban species.