気候変動の原因となっている温室効果ガスですが、発生要因として侮れないのが、家畜の吐く息です。
特に牛は大量のメタンガスを排出するため、畜産業全体での排出量は、地球全体の温室効果ガスの14%とも言われています。
それでも牛肉は食べたいですよね？
ビヨンドミートなどの代替肉ではない、もう一つの選択肢としてTEDでIsha Datarがスピーチしていますのでご紹介します。
New HarvestのIsha Datar
New Harvest は、アメリカのニューヨークとボストンを拠点とした、細胞農業を推進するNPO団体です。
主に、ファンドとしての働きを持っていて、投資家などからお金を集め、細胞農業分野の発展のために産業界や学術界にお金を投資しています。. 細胞農業は重要な分野でありながら新しく認知度の低い分野であったことから、従来の投資環境では研究費を集めにくく、それを解決しようとして立ち上がったのがNew Harvestです。 Isha Datar はこの団体でエグゼクティブ・ディレクターを務めています。
TED 要約
シンガポールには、殺されていないニワトリの肉から出来たチキンナゲットを食べている人たちがいます。なぜこんなことが可能なのか？これが、細胞農業の力です。
ここ数十年、研究所で筋肉細胞を培養し、ハンバーガー、ソーセージ、そしてチキンナゲットなどの食用にする研究をしてきました。
筋肉細胞に必要な成分を培養液に育てていきます。これで骨、皮なしの肉チキンナゲット用の肉を作り出します。
これは家畜に対してのみ役立つのではありません。従来の畜産に比べ、土地は99%減、水は96%減、温室効果ガスも96%減となります。実現することでこれまでの誤りを正し、農業を変革できると考えています。
誤りとはなんのことか。今のシステムは何十億の人の胃袋を満たすために設計されているため、例えばニワトリは50年前と比べると姿も形も変わり、食用に大型化しています。現在のニワトリは出荷の時期を過ぎると、自分の脚で体重を支えられなくなります。
家畜は牧場で高い密度で育てられているため、感染症のリスクが高いです。2018年にはアフリカ豚熱により地球の約4分の一の豚が処分されました。
気候変動の話をとっても、牛だけで温室効果ガスの9%を排出しています。気候変動による被害を考えると、今とは違う農業の形が必要なのは明らかです。
現在、地球の面積の27%、およそアメリカ大陸の広さの土地が、家畜を育てるために使用されています。細胞農業で世界のタンパク質のじゅよを満たすことが出来れば、熱帯雨林などの環境も破壊しなくて済みます。
国連は気候変動の進行に抵抗するには、中国全土程度の土地が必要としています。この解決策として細胞農業は有効です。
細胞の研究により、理論上は植物細胞や動物細胞からできているものはすべて培養できます。バニラは熱帯雨林で育てる必要がなくなり、卵の白身は黄身を分ける必要もなくなります。フォアグラ、革製品、シルクも動物や蚕無しで生産可能です。
牛乳を凝固させてチーズを作るためのレンネットという物質は、以前はあかちゃん牛の4つ目の胃袋から採取していましたが、1990年に培養されたものが市場に登場しました。以降、たった30年でチーズ製造に使われる90％のレンネットは培養されたものになりました。
レンネットのような高付加価値の物だけでなく、一般消費者が手にするアイスクリームにも、細胞農業は広がっています。必要なホエイ遺伝子をデータベースから取り出し、DNAの情報をトリコデルマといわれる細胞に注入します。これに糖を与え成長させることで、アイスクリーム、ヨーグルト、クリームチーズに使われるホエイプロテインになります。
ご紹介した内容は細胞農業の中でも簡単なものです。例えば肉の細胞農業には最新の細胞組織の設計が必要です。動物細胞の培養は大変難しい技術ですが、徐々に前に進んでいます。
2013年と比較すると、細胞農業での肉の価格は127,000分の１まで落ちており、今後も技術が進めばコストはどんどん下がります。一方で畜産物の価格は、コロナや気候変動リスクなどの影響で今後も上がり続けることが予想されます。
動物からとれる食材は素晴らしいです。のびるチーズ、クリーミーなカスタード、ふわふわのメレンゲ、肉やシーフードの極上の旨味などは格別です。
ですが、これらはすべて、実際の動物から採取する必要はないのです。
もちろん道のりは長いですが、人類が12,000年前に狩猟から農業に進化したのと同様の変化を起こすことが出来る可能性があるのです。
この技術の進化でできるようになることは想像もつきません。
私たちの遠い先祖はグラスに入った嫌な臭いもない牛乳を想像できたでしょうか？何百種類ものチーズを想像できたでしょうか？細胞農業により、肉は将来、泡や液体となっているかもしれません。
現在食べることが出来るハンバーガー、ソーセージ、チキンナゲットは始まりに過ぎないのです。
将来の食料に対して大きな夢を抱きましょう。
TED 原文
Diners in Singapore are eating chicken nuggets made from a chicken who was never killed. How is this possible? Through the power of what I call “cellular agriculture.”
For the past decade, I’ve been an advocate for growing meat in a lab. To me, this chicken nugget, this hamburger, this sausage — all made from cells instead of animals — aren’t just fast-food products. They’re our ticket to a new food system. Here’s how it works. Rather than raise a whole chicken with beaks, feathers, sentience, we grow the meat directly from muscle cells. We take a small biopsy from a living animal, and then extract the cells of interest. They’re probably muscle cells, but they could be fat or connective tissue as well.
Now, muscle cells in particular, love to attach onto surfaces. It helps them grow and elongate into those long muscle fibers that we’re so familiar with. So we might provide a scaffolding material for those cells to adhere onto. And then, of course, we have to feed the cells something. So we put them in a liquid medium that provides all the nutrients that these cells need to grow and divide: carbohydrates, amino acids, growth factors and more. Lastly, the cells on the scaffold in the medium all grow within a bioreactor, which is kind of like a large stainless steel tank — looks a lot like growing equipment and can be just as big as well. And the bioreactor really just provides that constant stable environment that those cells need to flourish in — stable temperature, pressure, inflows, outflows, etc. And after those cells get a chance to proliferate and differentiate, mature into muscle fibers, we might harvest the cells and the tissues and then turn them into a nugget, a nugget that was boneless and skinless and all white meat to begin with.
Now, this wouldn’t just be better for chickens and cows and pigs and the people who have to farm them and slaughter them and process their meat. This could be better for the whole world. Think of this: early estimates of cell-cultured meat’s potential show that cultured meat would require 99 percent less land, 96 percent less water and produce 96 percent fewer greenhouse gas emissions. Now, those are still speculative early estimates. But think about the incredible potential that this technology holds. I mean, if this all works, this would be a new subsistence strategy, a new tool set for producing food. It wouldn’t just be a new product category. And I think it’s our once-in-a-lifetime opportunity to get a second chance at agriculture, to do things better and to learn from our mistakes.
What do I mean by mistakes? After all, this is a food system that keeps billions of people alive, yes. But look at what has happened to chickens in just 50 years. By simply picking which two chickens to breed with one another, chickens went from this on the left, a bird that’s from 1957, to this on the right, a broiler. These chickens are the same age. Broilers have been optimized so much for meat production that they must be slaughtered at six to eight weeks, because if they live beyond that, their legs will not be able to hold up their bodies. That is real suffering.
What about farms? Today, animals are packed together so closely that the risk of antibiotic resistance and epidemic viruses are at all-time highs. Did you know that 2018 was the beginning of the largest farmed animal pandemic ever? African swine fever has already killed an estimated one in four pigs on Earth. One in four pigs, that is hundreds of millions of pigs lost from our food supply. Animal agriculture is simply too big to not fail.
What about our changing climate? Did you know that our global herd of farmed animals is one of the biggest drivers and victims of climate change? On one hand, cows alone produce nine percent of all greenhouse gas emissions. On the other hand, climate chaos is seeing more and more incidences of thousands, sometimes tens of thousands of cattle being lost overnight in rogue storms, floods and fires. Farming is always going to be at the mercy of Mother Nature, but climate change is rewriting the rules of farming as we speak. We need another way.
Lastly, our planet. We dedicate more of this Earth to feeding cows, pigs and chickens than we do to anything else. About a third of this planet, 27 percent, roughly equivalent to all of North and South America combined, is dedicated to raising livestock. Now, this could all change with cellular agriculture. Remember how I said it would require 99 percent less land to produce cultured meat versus beef? Well, think about it: ranching can’t go vertical, but cell culture can. And if we can alleviate half, even a quarter, of this land and meet the global demand for protein, well, imagine what we can do with the rest. Suddenly, it becomes possible to choose to do things like restore the Amazon rainforest, which we continue to clear-cut for cattle, or revive other ecosystems that have been colonized by cows, corn and soy. Or return stolen lands to Indigenous peoples, who can finally reclaim their ancestral foodways.
The United Nations says that we will have to restore nature on land the size of China if we are to achieve climate resilience. Cellular agriculture actually puts this on the table. Not only could we alleviate land for restoration, we can also create the products we know and love at a fraction of the emissions. By farming cells, we could actually proactively envision agriculture for a climate-changed world.
And it’s not just me. Actually, by engineering biology, we could theoretically grow anything that might come from plants or animals from cells instead. Vanilla doesn’t have to be rainforest farmed. Egg whites don’t have to come with a yolk. Foie gras can be completely cruelty-free, and leather and silk don’t have to come off the back of an animal or the home of a silkworm. In fact, we already consume cellular agriculture products in our everyday lives, just in supersmall quantities. Several vitamins, flavors and enzymes are already made in cell cultures. In fact, rennet, which is the set of enzymes used to turn milk into curds and whey for cheese-making, used to come from the stomach lining of the fourth stomach of calves, baby cows. And in 1990, a cell-cultured version hit the market. A version of the key enzyme, chymosin. And today, only 30-ish years later, 90 percent of rennet used for cheese-making came from a bioreactor instead of a calf.
Now, imagine what might happen if we expand beyond these small-volume, high-value products like rennet into commodity-level products like milk. Well, it’s getting started. Today, you can buy ice cream — real dairy ice cream — that was produced by cellular agriculture. This is cows milk that never came from a cow. It came from a computer. The gene for whey protein was looked up in an open-source database, printed and then inserted into the DNA of an organism called trichoderma. Now, just like in brewing, where we feed sugar to yeast to brew alcohol in a big stainless steel fermenter, we feed sugar to this modified trichoderma and out comes whey proteins that we can put in yogurt, cream cheese and ice cream.
Now, I have to admit that maybe this is the easy stuff, relatively speaking. I mean, we have been modifying microorganisms to make proteins for us for decades now. And tissue engineering, which is what would be needed for meat production, is a lot newer science. I mean, animal cells are just a lot more finicky than microbes in cell culture, and growing a lot of animal cells and achieving three dimensionality is just no easy feat. But we’re getting there.
Back in 2013, it cost 250,00 euros to produce this hamburger, and today, I’ve seen estimates of cell-cultured meats cost as low as $50 per pound. That’s one twenty-seven-thousandth of what it was less than a decade ago. And I can really only see the price of cultured meat coming down, and I can only see the price of meat from animals going up. I mean, think about it — we’re still in the early days of R and D. As scientific breakthroughs are made, like recycling growth medium, reducing the cost of growth factors and achieving higher cell density in vitro, this curve is still going to go down. Meanwhile, the price of meat from animals is already artificially low due to heavy subsidization. It does not reflect the cost to the public health or to the environment. And, in a world changed by COVID, African swine fever and a changing climate, the price of meat from animals can only go up. In fact, I think that price parity would be well within reach if it were an even playing field. On one hand, we have animal agriculture, which is so heavily supported by public funding and government support. On the other hand, we have this very promising technology, which requires very intensive R and D and needs a lot of infrastructure and training support but is left entirely in the hands of the private sector and market forces. In fact, I don’t think any of the wonderful things I just described about rewilding the Amazon and so on will happen if we leave this technology solely in the hands of technology and market forces. There’s a real chance that cellular agriculture could fail, and it won’t be because the science doesn’t add up. It’ll be because we didn’t think about what ownership should look like or IP protection or governance or policy — you know, the business side of mission-driven businesses. And we’re going to have to be very careful and thoughtful about what this technology needs around it so we can maximize the positive impact that it will have on this world.
Look, I’m here today because animal products are just amazing, and you would be hard-pressed to find proteins in the plant world that can do what animal proteins can do: long, stretchy cheeses, creamy custards, fluffy meringues, the incredibly rich umami flavors that you can find in meat and seafood … But despite how amazing animal proteins are, they just don’t need to come from animals anymore. And yes, we’ve got a long way to go to realize the potential of this technology, and it’s going to take ingenuity both inside of the lab and outside of it, too. But think about what we get in return. We get a chance to usher in a transformation as big for humanity as our transformation from hunting to agriculture some 12,000 years ago. This could be a new era of abundance in so many different ways.
I’m personally most selfishly excited for the food products that I can’t even fathom today, because this is really a new tool for culinary creativity as well. I mean, we haven’t really seen this since our ancestors discovered fermentation a while back. What I mean by that is, we could have never looked at a glass of milk before we fermented foods and wanted it to be hard and stinky and moldy. You know, we could have never envisioned cheese or the hundreds of varieties of cheese that we have today. Similarly, meat is still defined by the body of an animal. We still describe it as cuts of meat. But if we can grow meat from cells, suddenly the boundaries for what meat can be will totally change. Meat could be thin and translucent. It could be liquid. It could be crunchy, it could be bubbly. Burgers are the baseline and sausages are just a starting point, and nuggets are nowhere near what’s possible with cellular agriculture.
Let’s dream up a bigger, bolder future of food.
まとめ
温室効果ガスと聞いて思い浮かべるのが、工場の排気ガス、火力発電、自動車なのですが、畜産の与えている影響の大きさは驚かされます。
それどころか、倫理的な問題に加え、感染症など様々な課題を抱えている産業だと知りました。
日本では代替肉もまだ全く普及していませんが、世界のトレンドはしっかりと押さえておきましょう。
