01/12/2015 05:25 GMT | Updated 30/11/2016 05:12 GMT

Eating Less Meat Will Save the Planet... So Why Won't People Do It?

This weekend saw the biggest climate change march yet - London topped the global numbers, with a massive 50,000 campaigners taking to the capital's streets.

Predictably, many were marching in the name of fossil fuels - but then few would argue these need to stay firmly in the ground. A heartening number however, marched in the vegan bloc - showing a swelling number are starting to make the correlation between animal agriculture and the environment.

But despite the vegan contingent, many of the dedicated campaigners marching (some eating ham sandwiches en route) failed to grasp the irony of claiming to be an environmentalist, while contributing to the biggest factor in greenhouse gas emission (GGE) - which is of course, animal agriculture. According to some reports, the livestock sector is responsible for up to 51 per cent of GGE, as well as contributing 64 per cent of anthropogenic ammonia emissions - responsible for acid rain.

Meat production - especially beef - is a ridiculously inefficient and wasteful process, and the figures are eye watering. It requires around 16 pounds of grain to yield a single pound of beef - 660 gallons of water to produce a single cheeseburger. Growing and irrigating crops, harvesting them, processing and transporting them to feed to livestock, which is transported itself then slaughtered is Kafkaesque in its level of absurdity, and yet people continue to unthinkingly engage in this wasteful and destructive cycle.

As with everything, it's not an entirely simple equation - grazing land is generally not of sufficient quality to be used as agricultural arable land. But these are the questions that need answering. As the burgeoning population needs more space, where will the corresponding increasing number of livestock be housed? And what about the burgeoning corresponding harmful emissions? Clearly, something needs to change.

Going vegan is the single most effective way to reduce your footprint. We would save on this ruinous cycle, as well as feed billions more people, rather than feeding the grain to livestock. As the UN has said, the cultivation of livestock for food is 'one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global'.

With these leading global scientists pushing the connection between animal agriculture and the destruction of the environment, it really is time to wake up and smell the methane.