Climate change: science said, ‘eat less meat’. I obliged.

Last year, I became a father for the first time. I knew then that I’d have to make significant lifestyle changes. What I didn’t envisage was that I’d change the way I eat – and no, I’m not eating baby food!

A few months ago, I became a vegetarian, and I’m also cutting down on dairy products with a view of edging towards veganism. I now call myself a flexi-vegan. The link to me being a vegetarian with fatherhood is an odd one, but there’s a good reason for it. Of course, I didn’t go veggie for religious beliefs or health reasons – although there are definite health benefits in rich plant-based diets. I instead gave up meat because of environmental concerns. There is sufficient and robust scientific data to suggest that we need to take immediate and radical actions to avoid future catastrophe.

Skip to the last section for the TL;DR version.

The world population is projected to approach the 10 billion mark by 2050, and we need to find ways to feed future generations a healthy and sustainable diet. But eating meat isn’t the solution, but there is a solution, thankfully. The science has been clear for some time that eating meat with every meal isn’t good for the environment, and neither is it particularly healthy. (There are sound ethical reasons not to eat meat or animal products, but that’s outside the scope of this blog. See this article, which summarises some of the ethical reasons to give-up meat.) Over 200 international scientists have so far signed an open letter calling on city mayors to formulate new food policies to cut-down on livestock food products.


Let’s start with the work of the EAT-Lancet Commission on Food, Planet and Health. EAT-Lancet presented the first full scientific work to focus on sustainable global food systems that produce healthy diets. The report authored by 37 world-leading scientists from around the world found that “feeding 10 billion people a healthy diet within safe planetary boundaries for food production by 2050 is both possible and necessary,” which is great news. But in an unusually strong language for scientists, experts warn that we’ll fail to feed future generations if we don’t profoundly change our eating habits. They say that we need a “radical transformation of the global food system.”

The EAT-Lancet Commission recommends that we must double the consumption of fruits, vegetables, nuts and legumes and cut down on meat, especially red meat by more than half. Professor Walter Willett MD, one of the lead authors of the report, says: “A diet rich in plant-based foods and with fewer animal source foods confers both improved health and environmental benefits.”

The report nails it home with this summary: “Without action, the world risks failing to meet the UN Sustainable Development Goals and the Paris Agreement, and today’s children will inherit a planet that has been severely degraded and where much of the population will increasingly suffer from malnutrition and preventable disease.”

Global heating

In 2015, governments around the world reached a consensus in the Paris Agreement to combat climate change and limit the global warming this century to below 2 degree Celsius (2°C) and aim to restrict it further to 1.5°C. In 2018, a special report by the Intergovernmental Panel on Climate Change (IPCC) looked at implications of global warming between 1.5°C and 2°C pre-industrial levels.

91 world-leading scientists and policy experts from over 40 countries looked at the evidence from over 6,000 references and addressed 42,000 comments from experts before releasing the version. The resulting IPCC special report on Global Warming of 1.5 ºC is exceptionally rigorous; it’s the gold standard in the scientific review of climate science. Even the government representatives that water-down a lot of the summary approve the online version. So we can be confident that the findings of this report are undeniable.

The hard-hitting report made it explicitly clear that we must limit global warming to 1.5°C. If we fail to do so, consequences will be devastating for millions (possibly billions) of people in the future, including our children and grandchildren. It warns that “climate-related risks to health, livelihoods, food security, water supply, human security, and economic growth are projected to increase with global warming of 1.5°C and increase further with 2°C.” And to keep global warming limited to 1.5°C carbon dioxide emissions must decline by 45 percent between 2010 and 2030, and reach net-zero by 2050.

We’re already feeling the effects of global heating at 1°C rise. The Himalayas are melting fast, bringing water scarcity to hundreds of millions of people that are dependent on its glaciers. High temperatures are a breeding ground for pests and disease and prolong droughts, causing a severe threat to food security. Adversities at 1.5°C rise will be much more significant, and it increases exponentially at 2°C rise. Everyone will be worse off because of global heating, but it will cause further misery and disparity to widen the gap to the existing inequality, which is already significant. This blog summarises well the consequences of 1.5°C versus 2.0°C global warming.

Food and climate change

We can only achieve the targets set by IPCC if there are radical changes to industries that generate the most greenhouse gas emissions. Another IPCC special report provides evidence that the agriculture industry – as one of the most resource-intensive – must transform to stay within global warming targets. The IPCC special report on climate change and land, another mammoth IPCC report, is the work of 107 leading scientists from 52 countries worldwide. It drew evidence from over 7,000 literature and addressed more than 28,000 comments from expert assessors and governments.

Around 70 percent of our freshwater use is to grow food, while several regions face prolonged droughts and water scarcity. Agriculture is the single most significant cause of biodiversity loss as we clear forest to create croplands and pasture fields. Growing food releases the carbon – stored in the soil and vegetation – into the atmosphere, so the agriculture industry is also a prominent contributor to global heating.

The IPCC land report says that land, which absorbs nearly one-third of greenhouse gas emissions, is critical in our fight against climate change. Changes to land use affect the balance of greenhouse gases and other particles between the land and the atmosphere. And agriculture (the majority of which is for livestock farming) certainly changes the way we use the land. Human activities degrade about a quarter of ice-free land, and livestock production is the primary culprit.

Agriculture uses one-third of the world’s land surface and causes air, water and soil pollution. But most of agriculture’s land use comes from livestock farming, which is exceptionally wasteful. Despite taking almost 80 percent of global agricultural land, livestock produces less than 20 percent of the world’s calories supply (see the chart below or this link for more information). Producing food generates about a quarter of total greenhouse gas emissions, with animal-based food contributing 75 percent of that.

Chart credit: Hannah Ritchie and Max Roser. Our World in Data

Agricultural practices lead to deforestations and cause soil erosion up to 100 times faster than the soil formation rate. Planting trees on degraded lands can improve soil fertility, fix carbons in soils as well as protect habitats and prevent biodiversity loss. And reversing land degradation through “rewilding” can slow down climate change and global warming, which will give communities more time to adjust and prepare for the effects of climate change. But that’ll be impossible if we carry on eating more and more meat.

Plants absorb carbon dioxide for their growth, and forests store more carbon in their soils and biomass than croplands. Therefore, converting forests to forests to croplands releases greenhouse gases into the atmosphere. The IPCC land report says that nearly a quarter of total greenhouse gas emissions that we generate come from agriculture, deforestation and other land use. As we clear forests to create more land for agriculture, it produces a significant amount of greenhouse gases that fuel global heating. If we carry on with business as usual, temperatures will rise above 2°C by 2050, which doesn’t seem much, but the consequences will be catastrophic. Global heating is much higher over land than over the ocean; warming in the Arctic is up to three times higher than the worldwide average. And, of course, climate change and global heating have adverse effects on agriculture and food systems.

The IPCC land report says that “climate change negatively affects all four pillars of food security: availability, access, utilisation and stability.” Global heating and changes in rainfall patterns are already affecting the productivity of crops, livestock and fish, and as the effects of climate change get stronger, food availability will reduce. Climate change also affects the distribution of pollinators as well as exacerbating the risk from pests and diseases, which negatively affect food production.

The IPCC report on land says greenhouse gases emissions from animal-sourced food is larger than that of growing crops, especially in intensive, industrial livestock systems. If we eat mostly plant-sourced diets, it “reduces the need to raise livestock and changes crop production from animal feed to human food. This reduces the need for agricultural land compared to present and thus generates changes in the current food system,” says the report.

Agriculture and biodiversity loss

Earlier this year, the IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) produced a global assessment on biodiversity and ecosystems. This is the most comprehensive study of its kind; 145 experts from 50 countries worked for three years to compile the report. Scientists reviewed 15,000 scientific and government literature and tracked changes over the past five decades to provide a link between economic development pathways and their impacts on nature. The finding from IPBES global assessment sent shockwaves around the world.  

The IPBES says that 1 million animal and plant species face extinction within decades – and that’s a conservative estimation. The rate of biodiversity loss that we are now facing is more than ever before in human history. The report says that five drivers are directly causing biodiversity loss, the culprits are: (1) changes in land and sea use, (2) direct exploitation of organisms, (3) climate change, (4) pollution, and (5) invasive alien species.

Not just animals face extinction; plants species are also set to disappear due to human activities. Recent research found that almost 600 plant species went extinct, and humans have accelerated plants extinction by 500 times.

Now back to the IPBES analysis, which says that “for terrestrial and freshwater ecosystems, land-use change has had the largest relative negative impact on nature since 1970.” This is scientific language to say land use is the most significant contributor to biodiversity loss. And we know that agriculture, including cropping or animal husbandry, uses one-third of the land available to us. The report adds: “agricultural expansion is the most widespread form of land-use change,” which “has come mostly at the expense of forests (largely old-growth tropical forests), wetlands and grasslands.” More recently, a report found that an area of forest the size of the United Kingdom is lost every year. The study says: “the expansion of agricultural commodities [mostly livestock farming] continues to be the largest driver of deforestation,” and most of the deforestation happens in the tropical rainforests.

Cutting down on meat decreases land use. The land, which would otherwise be used for livestock, can be used to regenerate forests that can recapture carbon into the soil. Rewilding our land will improve our chances of slowing down global warming and staying within the 1.5°C target.

Another comprehensive study that reviewed food produced from 38,000 farms around the world concluded that “diet that excludes animal products has transformative potential.” The researcher who led this study said: “a vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification, eutrophication, land use and water use. It’s far bigger than cutting down on your flights or buying an electric car.”

With all the overwhelming evidence that meat farming contributes to deforestation, which in turn causes biodiversity loss and contributes to climate change, we need to rethink agriculture and food systems. And on individual level, we need to rethink out dietary choices. Meat and dairy products require pasture and feed for the animals, which often comes from croplands created by deforestation.

So with all the evidence, I couldn’t contribute to further deforestation and species loss just because I fancy eating meat. I’m a scientist, so it’s my duty to listen to science. And science is transparent: eating less meat and dairy products is the most effective individual actions I can take. That’s why I became a vegetarian and a flexi-vegan.

I know we need institutional changes if we’re to prevent further breakdown in nature, and that individual action isn’t enough. But if we take action collectively, it will make difference, and if a personal sacrifice will make the world a better place for my son and his generations to live, I’ll happily do it. That’s why I’m a vegetarian now.

You, too, can check the carbon footprint of your diet and how reducing animal products from your diet can help, or check your environmental footprint here. So every time you say no to meat, you are helping save trees and protecting nature – science says so, what do you say?

TL;DR version

I decided to quit eating meat because I’m a scientist, I’m a father, and I’m a concerned citizen of Earth. Climate breakdown and the ecological crisis are set to inflict unimaginable misery on future generations, and we need to take radical individual action as well as make an institutional change to curb the breakdown in nature. And the science is crystal-clear that cutting down on meat is the single most significant contribution that you and I can make to reduce our ecological footprint.

This evidence comes from several comprehensive, gold-standard scientific reports that were combined by thousands of scientists from across the world, who reviewed dozens of thousands of scientific literature. The IPCC special report on global warming of 1.5°C warns that climate-related risks to every aspect of our lives will “increase with global warming of 1.5°C and increase further with 2°C.” And to keep global warming limited to 1.5°C carbon dioxide emissions must decline by 45 percent between 2010 and 2030, and reach net-zero by 2050.

As it happens, agriculture, deforestation and other land use generate almost a quarter of greenhouse gases that causes heating leading to global warming, says the IPCC report on climate change and land. As we clear forests to create more land for agriculture, it generates a significant amount of greenhouse gases that fuel global heating. The IPCC land report says that animal-sourced food has larger emissions than crops.

Research shows that we lose forests – mostly tropical rainforests – the size of the United Kingdom every year, mostly to make way for agriculture. Livestock farming takes up 80 percent of agriculture land but only produces 20 percent calories. A lot of the area used to raise livestock comes from felling trees and forests, which causes biodiversity loss. Another landmark report on biodiversity and ecosystems from IPBES showed that a million species face extinction within decades – mainly thanks to the meat industry.

The IPCC land report adds that if we eat mostly plant-sourced diets, it “reduces the need to raise livestock and changes crop production from animal feed to human food. This reduces the need for agricultural land compared to present and thus generates changes in the current food system.” In other words, less meat means less land-use and deforestation (or more forests), which means less biodiversity loss (or more biodiversity).

The EAT-Lancet report says: “feeding 10 billion people a healthy diet within safe planetary boundaries for food production by 2050 is both possible and necessary,” which is great news. But experts warn that that if we’re to feed future generations, we need a “radical transformation of the global food system.” We must reduce meat consumption by at least a half to ensure that everyone eats foremost, and they eat healthy too.

Land freed from livestock farming can be turned into forests again, which can act as carbon capture technology to slow down global heating. Rewilding areas, which would otherwise be used to raise livestock, gives us a better chance of limiting global warming to 1.5°C. And we must do so to manage climate change better and avoid unspeakable catastrophe for the future generations, and for the many in the global south that are already facing the climate emergency.

We have a moral duty to do whatever we can to protect nature, and ultimately our own civilisation. And eating less meat is the most effective single action that you and I can take, says science. What do you say?

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