One of the main ways in which the livestock sector contributes to global warming is through deforestation caused by expansion of pasture land and arable land used to grow feed crops.  

Animal agriculture itself is also a significant source of greenhouse gases.  For example, ruminant animals like cattle produce methane, which is a greenhouse gas about 20 times more potent than carbon dioxide. Total emissions from global livestock are estimated at 7.1 Gigatonnes of CO2-equivalent per year, representing 14.5%  of all anthropogenic GHG emissions. (UN FAO)

According to another report published by the United Nations Food and Agriculture Organization (UN FAO), the livestock sector generates more greenhouse gas emissions as measured in CO2 equivalent – 18% – than transport. It is also a major source of land and water degradation. (UN FAO).

Beef is a bigger problem than other sources of meat.   Producing beef requires significantly more resources (e.g. land, fertilizer, and water) than other sources of meat.  As ruminant animals, cattle produce methane that other sources like pigs and chickens, do not.

It was estimated in 2014 that producing beef requires 28 times more land, 6 times more fertilizer and 11 times more water than producing pork or chicken.  As a result, the same study estimated that producing beef releases 4 times more greenhouse gases than a calorie-equivalent amount of pork, and 5 times as much as an equivalent amount of poultry. (Eschel et al, 2014)

Eating vegetables produces lower greenhouse gas emissions yet.  For example, potatoes, rice, and broccoli produce approximately 3–5 times lower emissions than an equivalent mass of poultry and pork (Environmental Working Group 2011).  The reason is simple – it’s more efficient to grow a crop and eat it than to grow a crop, feed it to an animal to build up muscle mass, and then eat the animal.)

Global Fishing Industry 

For many years we have known that the commercial fishing industry is depleting fish stocks to the point where they are unable to recover.  The 2021 documentary entitled “Seaspiracy” illustrates this point in a way not seen before.  According to the documentary, 13 facts stand out as proof of how the global fishing  industry is bringing our planet to a dangerous point.  Here, in brief are several disconcerting facts as highlighted in the film and other related studies: 

1. Empty oceans:  the oceans will be essentially empty by 2048. The film says that approximately 2.7 trillion fish are taken from the oceans globally each year.  
2. Fishing nets:  the Great Pacific Garbage Patch occupies an area of ocean approximately 1.5 million square kilometers in size.  An astonishing 46% of the plastic floating there is discarded fishing nets – quite a difference from the 0.03% of plastic straws that end up in the ocean.  
3. Protected marine areas: only 5% of the oceans are protected areas.  Sadly, a study has shown that 90% of those protected areas still allow fishing.  What is challenging are the resources needed to monitor and control illegal fishing that is often done at night.
4. Carbon sink: 93% of all carbon is stored in the oceans.  Per acre, marine plants store up to 20 times more carbon than land based forests.  Warming ocean temperatures are causing the ocean to lose its ability to absorb carbon.  Merely a 1% reduction of the ocean’s carbon stores is the equivalent of releasing emissions from 97 million cars.  
5. Plastic dumping:  the equivalent of one garbage truck load of plastic is dumped in the ocean EVERY minute.  There are now over 150 million tons of plastic floating in the sea resulting in the deaths of countless whales that ingest the plastic with their natural feeding habits.  
6. By-catch:  Commercial fishing boats and their enormous nets catch thousands of other fish that were in the same area as the desired catch.  It is estimated that over 300,000 whales and dolphins are killed each year as a result of by-catch and 250,000 sea turtles are either captured, killed or injured for the same reason. 
7. Fish farming:  fish farming as an alternative to wild fishing is not much better for the environment.  The film found that a single salmon farm in Scotland produces as much waste as a town of up to 20,000 people each year.  Farmed fish are raised in tight surroundings and susceptible to lice, anaemia, infectious diseases, chlamydia and heart disease.  
8. Human slavery:  commercial fishing often involves forced labor at sea.  Criminal groups behind some commercial fishing enterprises are responsible for the deaths of over 360,000 fish workers over a period of 5 years.  
9. Ocean trawling: ocean trawling generates a similar amount of carbon emissions as the global aviation industry.  Such trawling draws heavy nets across the sea floor that releases 0.6 – 1.5 gigatons of carbon each year.  Global aviation produces almost 1 gigaton of carbon each year for approximately 2% of all human-induced, carbon emissions.  Sediment on the sea floor acts as a carbon sink where emissions are stored.  Trawling nets disrupt the seabed and release the gas back into the water giving the oceans less capacity to absorb atmospheric carbon.  

For more information, please refer to www.earth.org for a better discussion of this and other related topics.