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This is The Guardian.

We now know that we're almost certainly going to breach 1.5 degrees of warming above pre-industrial levels in the next 5 years, sending the world into what the UN has called uncharted territory. This continued heating is going to have massive consequences for almost every aspect of our lives, including what we eat. We got a flavour of that earlier this year when UK supermarkets struggled to keep salad ingredients like tomatoes and cucumbers on the shelves, in part due to unseasonable weather in Spain and Morocco.

Asda and Morrisons are limiting the number of fruit and vegetables customers can buy because of a sudden shortage of certain products.

This time of year we import most of our fresh produce from abroad, places like Spain and Morocco, where the weather has been so bad that it's hit the harvests.

Across the country, fruit and veg aisles are increasingly bare. Tesco has joined Aldi, Asda and Morrison's in introducing rationing.

Not only is the climate impacting our food, but food is impacting the climate. Studies have found that food systems are responsible for a third of human-produced greenhouse gas emissions. So how do we feed 8 billion people without destroying the planet? And what will the future of our food look and taste like? I'm the Guardian's Science Editor Ian Sample and this is Science Weekly.

Rising temperatures doesn't just mean droughts and heatwaves. The weather is becoming more unpredictable, the timing and length of the seasons is changing, meaning our crops are no longer growing in their optimal conditions. It's time to rethink what we're growing and where. So I went to meet Helena Dove, the kitchen gardener at London's Royal Botanic Gardens in Kew, who's trialling alternative options for our future shopping baskets. I found her digging away in 1 of the beds.

She walked me to a greenhouse where we could chat in the warm.

Yeah so then we went into

the actual kitchen garden past our lovely mushroom bed which is another experiment but going quite well.

It turns out that the kitchen garden she runs is the ideal laboratory for testing what we might be eating in the next few decades.

So kitchen gardens were always put in a warm spot. That's why they're walled is to try and keep some heat in. But this 1 particularly is in basically the center of London. It wouldn't have been at the time, but it basically is now. It's got the wall and it's got a flight path overhead, which all adds to being slightly warmer.

I live about 20 minutes out of town and we're usually about a degree warmer here than I am at home, which just shows you. So we have a really warm climate for us to experiment with crops that might be growing in this country in a few years time because we have that added warmth.

So what are some of the crops that

you might be looking at? I mean, are you looking at alternatives to crops that just aren't going to fare well in either a more chaotic climate or in just hotter, drier temperatures?

Yeah, I focus on a few different aspects of it, but 1 of the biggest things that comes along with the warmer climate are more diseases. And we have crops that are really affected by a disease called blight. So blight affects tomatoes and potatoes, they're in the Solanaceae family, and blight needs water and warmth to spread so it needs to be about 24 degrees and we've been getting that earlier and earlier which means our crops are quite affected. Blight will basically take down all those crops overnight. I mean, literally overnight.

I'll tell anyone it happens on a Friday night. So when you get on a Monday, it basically turns them to mush and it stinks. So we're looking at things like what could we grow alongside them that doesn't suffer from blight but gives you the same sort of fruit so alternate roots for example and different fruiting crops.

And it's part of

the problem that we've been growing and sort of breeding I suppose a lot of these crops for things we really want those flavour, sweetness, shelf life, things like that, rather than actually resilience to survive when they're actually being grown.

Yeah, that's been a big thing. So the tomatoes are a great example. So when we get a tomato from the shops, they want it to be uniformly red. They want the skin to be relatively thick so that it doesn't bruise. So they've been bred and bred and bred over hundreds of years.

Tomatoes traditionally have green shoulders, the tops are quite green. Part of the breeding process to make them more red accidentally switched off 1 of the resilient genes. So we don't do it on purpose but we have bred it out and the other thing we do is we grow everything in what we call monocultures so they're quite prone to attack so it's twofold it's how we've been breeding our crops and how we grow them and we're not resilient at all.

So what are some of the alternatives you can look at for say tomatoes

I think potatoes as well?

The best thing to do is to go back to where they're growing originally and see what else is growing alongside them because if we can get the tomato and the potato to grow over here then we can get the other crops to grow over here in time. When both those crops first came over, they didn't grow well in this country. But for example, the potato grown in the Andes, and it's part of what we call the Andean 5 root crops. So there are 5 crops that most of the farmers over there grow all together in the same field in case 1 of them fails, so we should probably be looking at how that works as well. Part of those is something called ochre, which is a tiny little root, has a lemony flavour.

It's growing quite well in the UK, it still needs a bit of breeding time, probably another 20-30 years until it's giving us a big harvest, but it grows really, really well and it's resilient to blight. Another few that we're growing with this Andean 5 is 1 called Mashua, which is a climbing nasturtium. It's kind of a mustardy flavour. I really like it. It stores well, it grows well.

It's a climber, so it doesn't take up loads of room. You can eat the leaves, you can eat the flowers. It's a real, I call it a good doer because it does everything, it's pretty. But when we're growing all these things, it's not that we're never gonna grow the potatoes. I mean, we're standing right next to the potatoes that are chitting and ready to go out.

It's just that we wanna grow them alongside things.

Are there alternatives for tomatoes as well?

Yes, there are. So 1 of the big things I can easily grow is tomatillos or tomatillos, depending, I'm always told I'm not saying it properly, which is the Mexican tomato. It's not directly related. It's not like a brother or a sister, it's more of a cousin, doesn't get blight and it produces these beautiful fruits. They're green and they come in a little kind of lampshade type thing, like a little husk.

The issue with them is they all come at the end of the summer and you can just about eat them raw but they're better cooked. But their flavour is amazing, they make amazing salsas, that's what they're used for traditionally. They're abundant, as we breed them more, we might be able to get them to fruit a bit earlier, so along the lines of when we get tomatoes. The other thing we've got going, which is not ready to grow outside yet, it's a real 1 that might be 30, 40 years away, is the tomato tree. So we grow that indoors and it fruits all year round, which is great.

It's also a perennial. So it's quite a sustainable way to grow things as well.

And what are the fruit like on those?

They are like big plum tomatoes. They're not necessarily as sweet, especially the ones grown in the winter, but in my humble opinion, no winter tomato is as sweet because it's not getting the sun.

Are there

more resilient versions of some of these crops, like tomatoes, potatoes, out in the wild that, you know, researchers could go out and just look for to see if they already exist. And is Kew involved in sort of grabbing some of those species to bring back and try and understand?

So we've actually just been part of a project called the Crop Wild Relative Scheme, where our scientists have gone out into the wild and worked with local scientists to find the wild crops and where they are thriving. The reason that's really important is a lot of our crops are not doing very well, whereas you've got wild tomatoes and wild aubergines that are doing really well because they're not being interfered with, they're able to kind of evolve on their own. So if we can save those seeds and then we bring them back and we've stored them in the Millennium Seed Bank which is over at our sister site in Wakehurst, but there are lots of seed banks around the world that are involved in this project. The next step is that some of these seeds are sent out to the breeders so they can start working. So I know that the carrot seeds that our scientists found are now going out to Iowa and are being used in a scheme over there to breed carrots.

Carrots are quite fussy, so we need less fussy carrots. So it's a really great thing and we can build that resilience back in. We might lose things like sweetness, but I'd rather eat a less sweet thing than not eat at all. So it's that kind of future we're thinking about. They would just lose water.

They do wilt quite fast. So this is a

sprig of the tomato tree.

Yep and then you just whack it

in there.

That's it! So yeah a lot of plants happily just regrow from axils.

So what's the situation we

have to get to, Helena, from where we are now, where we have these crops which are sometimes struggling with the climate that we're now having to go through, and this sort of future where we hopefully go back to having more resilient crops?

1 of the biggest things that's going to change is we are going to grow more different crops in a smaller space and we will be okay with things not working, which at the minute is, you know, the biggest embarrassment. Oh, my tomatoes didn't work, it's very embarrassing, but we might be okay with that because our tomatillos have given us a massive harvest. I think we'll be looking more at the wild plants of, for example, the UK and the UK, the Americas and the Americas. So we don't eat a lot of what is edible in the UK, which might mean more cabbages, but also more wild plants. So I think we'll look at that.

And I just think that it will be kind of a smaller system. I do still think we'll buy from abroad, I think everywhere will, but I think it'll be much more of a going back to the Victorian times when, you know, an orange was a real treat. I think we will value our crops a lot more. I think we'll have an understanding of what happens when we can't get them and hopefully see them as the gift that they actually are.

So our diets will need to be more local, more seasonal, but that doesn't necessarily mean they'll be less varied or exciting. At least, not if my next port of call has anything to do with it.

Hi, how

can I

help you? Hi, I'm Tiziana, so

I've got onions. You've got what?

Onions, I've been chopping the onions so you don't have to. How do I pronounce your name? Tiziana. Tiziana? Tiziana, yeah.

Is she an artist? I'm an artist? No, no, no.

I wondered if Tiziana di Costanzo was an artist because there was a rail of white coats and aprons at her front door, but I was about to find out the real reason for them. She led me through her garden to a shed at the back. This takes me back to my lab days. If you've got any safety goggles I'll be right at home. What have you got in here?

Smelly stuff.

Inside the shed were boxes and stacks of trays full of bran and in those... Oh goodness.

These ones are really tough for the fish.

They're quite big aren't

they? They're very wiggly and they taste. Well it's not to everybody's taste the Morioh worm. They have a bit of an aftertaste.

Yes, if you didn't catch that it was Morioh worms, a kind of mealworm. Tiziana was producing insects, mealworms, crickets, locusts in a shed in her back garden. Her farm, Horizon Insects, started as a school project her son was doing. Tiziana was enthralled. The insects were an environmentally friendly alternative protein source.

Being at the bottom of the food chain, insects tend to be rather prolific. Quickly she found herself with thousands.

All made with upcycled material, our racks, and then that's how you can fit hundreds and hundreds of kilos in a very small space. And the beauty of it is also that they don't drink, so you don't have to give them water. So unlike meat, where you require 22, 000 liters of water to produce 1 kilo of beef. Here they just basically draw the moisture from apple peels and other vegetable peels.

So that's what you've got on top of the bran.

This

is a bit of carrot,

a bit of apple maybe.

We would get surplus from our local fruit shops, vegetable surplus, and there's so much wastage produced locally. You know, the outer leaves of cabbages or even bananas and things that have gone a bit to waste and convert them with the insect into edible protein.

It looked like a very efficient and sustainable food, if not a bit wiggly and jumpy. Even the insect's waste could potentially find a purpose.

Insect excrement is this, it's called frost, it's basically a highly valued fertilizer.

So can people eat this as well or is this just for a fertilizer?

No, we haven't eaten it But we did have a lady asking could she maybe make a face mask out of it.

And is there any reason why you want to make a face mask out of insect eggs?

I have

no idea. I have no idea.

Well it's amazing what there's a market for.

I feel free to try.

I think I need 1.

After inspecting the insects it was time for me to try them and luckily I'd been booked onto 1 of Tiziana's cooking courses. Laid out on the table were your usual ingredients, eggs, onions, spices, coriander and locusts, mealworms and crickets. Despite them being rich in protein, vitamin and minerals, I felt I needed a better reason to be putting them in my mouth. So how is it benefiting the environment to be eating insects like this?

Well, first of all is the land usage, which is substantially less compared to traditional livestock, because you can farm them vertically. The WWF estimates 37% of our land on the planet is used for either growing crops or crop which will go into animal feed. There is also consideration about what you feed them and agri-food waste can be reused for feed for insects. And also this, the advantages of having yet another source of protein alternative to fish, which will allow the oceans to replenish.

Right, so what are we going to make today? Should we get cooking?

Yeah, okay. So today I just thought we'd do a fritta, which incorporates dried mealworms. We encourage our guests that before you put any spices on you should try Just without any seasoning just so that you're sure that you're gonna like it So Ian help yourself to a couple of mealworms, please.

You want me to try 1?

Yeah, if you don't mind.

Oh goodness. I don't want to do it. Oh god. Oh, they are dead but like um what is it like it is very light it's almost sort of rice like It is quite a little bit nutty. It's very crunchy.

It's not unpleasant, which I completely was expecting. It's unpleasant to put it in your mouth, for me. While I was tackling the strange array of sensations and emotions of eating mealworms for the first time. Tiziana thought I might enjoy them more if they were in something. So we got frying.

Have you got a favourite insect for eating?

Probably the mealworm is the easiest 1 to snack on. Some people like to snack on nuts and we like to snack on mealworms.

Do you take a like a little bag out with you when you go on trips?

Yeah yeah absolutely.

Do you ever offer them around when you're on the

train? No, I dig some funny looks though.

What place do you think these kinds of insects would have on our plate, on our menus?

I think, I mean, my utopian view is that every neighborhood will have an insect shed like the ones that we have and that people you know could grow the food directly where is needed just with the shortest food chain possible and that you know more restaurants will embrace them, more people will start experimenting with them and incorporate them into regular food, even in the form of flour if we find that there is a reluctance in wanting to embrace the full insect. However, I mean, as you've seen, that's easily overcome. Once you try an insect once, then you realise that really, what's the fuss about? It's just food.

So we fried up our mealworm fritters and they look spectacular. I have to say, should we try 1? Yeah, very light. That's tasty as well.

I could probably put more chili in that, but that's good.

I like it.

It's a little salty.

It's a little salty. It's a little salty. It's a little salty.

Okay, so the fritters were good, but they left an interesting aftertaste for the rest of the day. But if the climate crisis continues on its current path, In the future we're going to have to embrace foods that seem a bit alien to us, whether it's different types of plants or insects or totally new kinds of food altogether.

There are some components, mostly animal based, that have been produced there at the back, very differently, such as producing milk without cow, egg without chicken and proteins.

That's Pasi Vainikka, co-founder of a company called Solar Foods.

There is a route to grow biology by using electricity instead of sugars or sunlight as a primary energy for growing something living that could be also eaten.

Solar foods.

What Pasi is describing gets to the heart of what Solar Foods does. In a big laboratory, they take a microbe, feed it, and then turn that frothy soup into a bright yellow flower. In other words, this is food made from bacteria.

So simply what we're doing, we have our microbe that we provide with growth conditions. So those conditions where it can grow and multiply in a fermenter. It's like a big soda stream. We bubble in hydrogen that we make from water with electricity, so the electrical energy is charged in a chemical form in hydrogen. We bubble that in, and also carbon dioxide.

And these 2 are the main feedstock for the organism. We take the liquid out, dry it and you end up with a dried powder called solene, nutritionally very close to dried meat.

Solene is designed to provide lots of nutrients that can be difficult to get from a vegan diet without damaging the environment, a key goal in a warming world. Thankfully, on this occasion I didn't have to try anything, so I asked Pasi what his bacterial concoction tastes like.

There is a hint of carrot, mushroom-ish, umami-ish flavors that you can taste if you have it raw. You never do have the powder raw, but the bottom line is it's very neutral and the taste of food where solene appears, you make to the final product as you are flavoring dough, for example, for whether it's pizza application or cinnamon bun. My favorite definitely is ice cream. What happens is that for a reason or another, I'm not a food chemist, I have to admit of course. It forms a really creamy, full texture to yogurt and ice cream applications.

So how does the carbon footprint of solene actually compare to other foods?

Roughly speaking, what we see on average is that the environmental impact of solene compared to red meat is about 1% and

10%

compared to that of plant-based foods.

In the case we're using renewable electricity to generate the hydrogen what we need for our fermentation. Sounds great but we don't want to eat just solene. So I wonder where Pasi saw it sitting within our diets in the coming years?

We could provide milk, dairy products, meat-like products and that nourishment at every meal of the day. But then the real meat, the real dairy produced in a traditional way, maybe we can scale down the volumes of the production in the future to 1 fifth, but maybe we can afford to take the price point fivefold in the future. So the traditional meals with family, festive occasions, Christmas, all that can remain the same, but maybe you can afford to pay 5 times more.

Just like Helena at Kew pointed out, more environmentally damaging foods are going to have to be viewed as treats in the future. If, like me, you're wondering whether this could be a little bit miserable. Pasi didn't see it that way. It's all about finding solutions like tomatillos, insects and maybe even bacteria to keep our diets appealing in a changing world.

Let's take lasagna. There is the wheat flour base for the pasta part, maybe tomato sauce also, but the meat can be cultivated meat or it can be plant-based meat or a microbial meat provided by us, but the food experience remains the same.

A huge thanks to Helena Dove at Kew, Tiziana de Costanzo at Horizon Insects and Pasi Wajnicka at Solar Foods. And that's it from us today. The producer was Madeline Finlay, the sound design was by Joel Cox and the executive producer was Ellie Burie. We'll be back on Thursday. See you then.

This is The Guardian.