The search for carbon-neutral protein 4np67

Of course, avoiding meat and dairy altogether is the probably single biggest way to reduce our environmental impact on the planet, according to scientists and environmental campaigners. The largest analysis to date of agriculture's impact found that while meat and dairy provide just 37% of protein, they produce 60% of agriculture's greenhouse gas emissions and use 83% of available farmland. 

"The closer you get to the ground, the less of an impact you will have on the climate," says Sujatha Bergen, head of health campaigns at the Natural Resources Defense Council, a US-based environmental advocacy organisation. "The more plants you eat, the better."

But dairy is, for many people, a major source of calcium and protein, along with other nutrients including vitamin B12 and iodine. Consequently, many nutritionists insist that milk products still have an important role to play in our diets, as do other non-meat animal products such as eggs. 

Compared to dairy, eggs have a much lower carbon footprint, which makes them an attractive source of protein. Yet, the environmental concerns surrounding dairy and egg production extend beyond their carbon footprint. 

Producing feed for hens uses large amounts of land, energy and water. Feed production s for 75% of the poultry industry's carbon footprint. Many experts argue that the land allocated for feed production could be better used to grow crops for people. 

Many of the environmental costs linked to dairy production are also hidden. The industry has a major impact on biodiversity loss and land degradation. Cheese, butter and chocolate sold in British supermarkets are linked to widespread deforestation in Brazil's Amazon and Cerrado regions, according to an investigation by Greenpeace, while intensive dairy production in the European Union has been linked to soil contamination and groundwater pollution. 

"Dairy milk is by far the most impactful [milk], from a land and water-use perspective," says Bergen. "The best thing we can do is reduce our consumption and switch to alternatives." 

Soy milk, one of the most popular dairy-free alternatives, for example, has a significantly lower carbon footprint than cow milk. It takes 14 kilo-calories (kcal) of fossil fuels to produce one kcal of dairy milk, compared to just 1kcal of fossil fuels needed for 3.2 kcal of soybeans. But soya production has its own environmental problems and is a major driver of deforestation in some parts of the world.

So, can we produce diary and eggs in a more sustainable way that allows us to keep them in our diet, but reduce their impact on the planet?

In New Zealand, the company Fonterra has found another possible solution to cattle's climate problem. Fonterra has been collecting cultures used to make milk, cheese and yoghurt for more than 100 years. The company is using some of these to create probiotics – cultures of live microoganisms – that might help to inhibit bacteria in the cow's gut that produce methane. Their product is Kowbucha – a play on the name for the popular fermented drink kombucha, which contains probiotics that might improve digestion and create a more balanced microbiome in the gut. 

"We are doing something similar to kombucha for livestock. Kowbucha can switch off the bugs that make methane inside the cow," says Shalome Bassett, Fonterra's principal scientist.

Initial trials in the lab are promising, says Bassett. The results, which are yet to be published, show that adding Kowbucha to a dairy cow's diet can reduce its methane emissions by up to 50%, according to Fonterra.

Fonterra is currently testing the product on calves, adding the supplement to their feed. Next year the company plans to test the product on more mature animals and other livestock, including sheep. If successful, it could be an important development for New Zealand. Methane from agriculture and waste makes up 40% of the country's total emissions and is largely to blame for its poor climate record. 

"The race is on to find a viable solution to this methane challenge," says Bassett. "[With Kowbucha], we can continue producing dairy for years to come."

Van Nieuwland from DSM says there is enormous demand for methane-busting products such as Bovaer. "It is really driven by consumer demand and the sustainability goals that companies have set," he says. 

At the COP26 summit in Glasgow, UK, in November, the United States and European Union launched a global methane pledge, with the aim of reducing methane emissions by 30% between 2020 and 2030. More than 100 countries have signed up to the pledge so far. 

Van Nieuwland says the global commitment should help accelerate efforts to cut methane in agriculture. "It helps to have a common goal and a focus," he says. "It also allows a level playing field – nobody wants to be left behind." 

But while cutting cow burps is one approach to reducing the impact of dairy farming on the planet, some are looking to cut out the animals altogether by producing milk from cell cultures instead. Perfect Day, based in Berkeley, California, for example, have introduced the genes for certain cow milk proteins into a fungi so they can produce milk in a laboratory. 

Another approach taken by TurtleTree labs in Singapore has been to grow mammary cells from cows in bioreactors so that they can produce milk. Although these efforts are still costly compared to traditional dairy and there are still some regulatory hurdles to be overcome, there are signs cellular agriculture could become a valuable source of protein in the future – Singapore recently became the first country in the world to approve the sale of lab-grown chicken meat.

But while growing animal products in a laboratory from cells is an appealing idea, it remains experimental and could be decades away from being able to provide food on the scale needed. Globally around 227 billion gallons (1 trillion litres) of milk were produced in 2020 while the world consumed around 1.3 trillion eggs in 2018. It means more traditional methods of production will be needed for some time and so some farmers are seeking new ways of reducing their impact on the environment.

Dutch poultry farmer Ruud Zanders was unhappy about the mass production practices on chicken farms, where the priority was always "making as many animal-based products for the lowest price possible".

While on a trip to Africa in 2013, he was asked by farmers why in developed countries good-quality grains and maize are fed to animals, rather than saved for human consumption. "I thought to myself 'why are we doing that?'", he says. "I wanted to farm in a completely different way and [explore] whether there is a role for animals in feeding the world." 

When trying to set up an environmentally friendly farm, Zanders consulted academics researching sustainable food systems at Wageningen University in the Netherlands. "They explained to me that if you want to help feed the world in a sustainable way, you have to avoid direct competition between people and animals," he says.

The eggs are sold in supermarkets across the Netherlands. "We were completely sold out from the beginning," says Zanders. He puts the success down to Kipster's sustainability record as well as its focus on animal welfare. The farm has received the "Better Life" label from the main animal rights' charity in the Netherlands. 

Next year Kipster plans to expand internationally, opening poultry farms in the US, Belgium, , and the UK. 

But Zanders says that sustainability changes alone aren't enough to solve the climate problem of the dairy and egg industries. "I know it sounds strange to say as a poultry farmer, but we have to eat fewer eggs," says Zanders. "I think we have to give up many animal-based products," he says.

According to research by Wageningen University, even if we use land in the most optimal way and use leftover products as animal feed, we can only consume 20g (0.04lb) of animal protein per person each day. In the Netherlands, the average person eats almost 50g (0.11 lb) too much protein per day, with 60% of the protein intake coming from animal-based products. If we want to eat animal products with no guilty conscience, we should start by cutting down on our consumption.

"A lot of people focus on incremental changes, but we need an entire food system change," says van Zanten.