October 2011. Do you remember where you where around that time? If you do then you’ve certainly got a better memory than me! But it was actually quite a significant date, because it was when the world’s population reached 7 billion people. After growing very slowly for most of human history, the number of people on Earth has more than doubled in the last 50 years.
And what’s more, that figure is expected to reach 9 billion by the year 2050.
This huge increase in the number of people on Earth is going to put a lot of strain on the world’s infrastructure. More people means more energy is needed to power homes and transport.
But one of the key challenges facing us is how do we feed everyone?
And with many people around the world living in hunger, this is an especially sensitive issue. So how can science and engineering find innovative ways to help solve this problem? And can it be done sustainably?
Feeding our growing population is putting more and more pressure on our land. On a global level, the main solutions lie in effective distribution of the food that we currently produce, and making the most efficient use of land. However, what if the land space available to us is limited? Taking the UK as an example, 50% of the food that is consumed has to be imported, and that raises further environmental issues because of all the food miles. Demand for food is also greatest in densely populated cities, where it is hardest to grow crops.
That’s where urban farming with a difference comes in.
It’s the latest in cutting edge, innovative and sustainable food production. Crops can be grown indoors, with artificial sunlight, and in a very small space. This means that plants and crops can be grown 24 hours a day!
Yes, scientists are making indoor farming even more viable, by abandoning natural sunlight altogether. The sun of course is the usual source of energy for plants, and what looks to us like white light is actually made up of different wavelengths of visible light – different colours if you will. When white light is refracted in water droplets after it rains, it splits up and we see a rainbow. Plants use all the different visible light wavelengths for photosynthesis, the process by which they use light to convert carbon dioxide and water into sugars and oxygen. But they don’t actually need the green light wavelengths, so they reflect the green light back. And that’s why plants look green to us!
So if the plants don’t need the green light, surely they can grow without it, right?
Scientists have run experiments with plants using different colour wavelengths, to find out which is more suited to plant growth.
The results show that red and blue light is most efficiently absorbed by the leaves of the plants, and most efficient for photosynthesis.
And by cleverly using LED light bulbs instead of normal light bulbs, more plants can be stacked on top of each other (just like rows and rows of shelves in a supermarket) since LED lights stay cold (unlike normal light bulbs which become very hot) and therefore cannot burn the leaves of the plants! Stacking the plants in shelves reduces the amount of space required for growing, so a lot more crops can be grown in very little space.
Clever, and as well as saving space, LED lights are also more economical as they are 30% more efficient than conventional lighting. Very clever.
While it seems almost like a perfect solution, it’s not quite that simple. There is still a lot to learn about the best ways to grow the plants, but the potential is definitely there. This type of farming tackles so many of our sustainability issues, and it’s all about having the vision to think long term.
It just goes to show, it doesn’t take a bright idea to create something new, just a blue and red idea!