Since the industrial revolution in the 1800s, average global surface temperatures have risen by 0.85C . This may not seem like a significant increase to us, but it has occurred over a very short period. The suddenness of this change has meant that many species, including humans, have not had enough time to adapt.
Already, 300,000 human deaths every year are linked to climate change , globally. Already, climate change has been linked to the outbreak of the Syrian Civil War , where thousands of humans died and were displaced. Already, we are seeing increases in the frequency and severity of extreme weather events such as heatwaves [4; 5], droughts , flooding , hurricanes  and wildfires .
All of this with just a 0.85C temperature rise, and we are currently on a trajectory for a global average temperature rise of 3.2C . In the future, we are likely to see significant decreases in crop yields in many areas of the world , with areas of Northern Africa and the Middle East potentially becoming uninhabitable [12; 13].
Animal farming and fishing is responsible for, at a minimum, 14.5% of all greenhouse gas emissions worldwide  (more than global transportation). This is the most conservative estimate available, as it does not include key sources of carbon emissions such as deforestation for pasture and animal feed. Despite this, it still concludes that animal agriculture is a leading contributor to climate change.
As part of this, animal agriculture contributes 37% of global methane emissions and 65% of nitrous oxide . These gases are much more potent than CO2, having global warming potentials of 56 and 280 times that of CO2  respectively over a 20 year period.
The combination of these facts makes animal agriculture one of the biggest (if not the biggest) contributors to climate change.
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