Rooftop farming

A Bangkok-based  start-up called EnerGaia is pioneering a unique urban farming model. Across the city's neglected rooftops, a small team of chemists and engineers are growing a nutritional supplement which also happens to be one of the planet's oldest life forms: spirulina.

This organism is a fast-growing blue-green algae with an estimated protein content of 60 percent and contains essential fatty acids and vitamins. In fact, this superfood grows rapidly without the need for soil or fertilisers and can convert carbon dioxide from industry into to a highly nutritious food.

As our global demand for food increases and our appetite for protein-rich sustenance grows, could spirulina be one part of the solution?

Join Russell Beard in Bangkok as he meets the team spearheading a new generation of urban spirulina farms.

Sustainable seafood

Growing demand and industrial fishing techniques are pushing some populations of cod and tuna to the brink of collapse. Meanwhile, millions of tonnes of less marketable fish are used as fertiliser, fish food, or simply discarded. According to some experts, 90 percent of the world’s fish stocks are being fished at or beyond their sustainable limits.

Soleshare, a tiny startup based in east London, is challenging this worrying trend by encouraging its members to do one thing – eat a wider variety of sustainably-caught fish.

"I used to work in conservation so it's a bit of a strange step for me to go from saving fish to now saving fish through eating fish," explains SoleShare co-founder Jack Clarke. "But there are methods of fishing that need support."

SoleShare sources all of its fish from local, small-scale fishermen who use static nets to avoid catching juvenile fish and inflicting the kind of seafloor damage caused by industrial trawlers. SoleShare customers support these fishermen by giving them a good price for whatever fish they catch, helping ease the pressure on cod, tuna, prawn and salmon populations and keeping small-scale fishermen in business.

Sylvia Rowley joins a fisherman off the coast of Newhaven and takes part in a SoleShare workshop designed to get customers hooked on sustainable seafood. 

Recycling phosphorus

By 2050, it is estimated that rising populations and changing diets may lead to a 70 percent increase in global food demand.

One ingredient, which will play an important role in making sure we have enough food to feed ourselves, is phosphorus. This mineral is vital to plant growth and is a key component of fertiliser.

Yet, according to some experts, minable reserves of phosphorus may be completely depleted in a few hundred years.

We also continue to use excessive amounts of phosphorus in agriculture, which creates problems such algal blooms and nutrient pollution when the fertiliser runs off into our waterways.

One sewage plant in London, however, is dealing with both the shortage of phosphorus and also the environmental damage its inappropriate use causes. Using technology developed in Canada, the plant is turning faeces into fertiliser and creating a new, greener way to grow crops.

Join Amandeep Bhangu in London, UK as she visits Europe's first facility that is turning raw sewage into fertiliser. 

Source: Al Jazeera