There is one lifestyle choice we can all make that could take us halfway to reaching our climate goal of 1.5 °C (2.7°F) or less above pre-industrial temperatures by the end of the century, according to a new study – and that is to go vegan.
Giving up milk and meat might not sound like a particularly appealing option but according to an article published in the journal Climate Policy, the global livestock sector could exhaust almost half (37 to 49 percent) of the 1.5°C greenhouse gas emission budget allowed by 2030. And so one of the best things we can do to meet the Paris target, says Helen Harwatt, farmed animal law and policy fellow at Harvard Law School and study author, is to adopt a plant-based diet. Aka a vegan diet.
Around 28 billion animals are currently being farmed for human consumption. Combined, they are the most prolific generators of two greenhouse gases – methane and nitrous oxide.
While carbon dioxide (quite fairly) receives the most attention as far as climate change is concerned, methane has 85 times the global warming potential of CO2 in the short term, making it a hugely significant contributor to rising temperatures. What's more, according to Harwatt, methane emissions attributed to livestock are expected to rise by a staggering 60 percent by 2030.
"Failure to implement animal to plant protein shifts increases the risk of exceeding temperature goals and requires additional, and unrealistic, greenhouse gas reductions from other sectors," Harwatt said in a statement.
"The current revision of national contributions to meeting the Paris Agreement from 2020 onwards should ideally integrate animal to plant-protein shifts. As a next step, the COP24 in December this year provides an excellent opportunity for policymakers to start this important conversation."
To transition to a plant-based world, she outlines a three-step process.
First, acknowledge that we are at "peak livestock" – that is that livestock numbers will have to decline from now on. Second, introduce targets encouraging the shift from animal products, beginning with those (like beef and lamb) that have the highest greenhouse gas emissions. And third, assess suitable replacement products, considering greenhouse gas emission targets, health benefits, and land use.
It's fair to say that it is unrealistic to expect the whole world to switch to veganism, particularly within the timeframe needed. Even if it did, it would only take us so far towards reaching our climate commitments – one-quarter of global emissions are due to energy production, 21 percent comes from manufacturing, and another 14 percent from travel. But in some parts of the world, it looks like people are starting to adopt a diet that is much more plant heavy of their own accord, whether that is for environmental, ethical, or health reasons.
In the UK, the number of Brits identifying as vegan has shot up from 150,000 to 600,000 in the last four years alone. What's more, a third have intentionally stopped or reduced their meat intake. Meanwhile, in the US, the number of vegans and vegetarians has remained pretty stable over the last 20 years or so – but that doesn't mean people aren't actively consuming less meat and dairy.