Scientists are looking at new ways to overcome inevitable food shortages linked to climate change. Enter ocean flexitarianism - an environmentally friendly diet, rich in algae and seaweed.

Patricia Harvey, professor of biochemistry and head of bioenergy research at the University of Greenwich in the UK, is pioneering a new approach to ethical consumption dubbed ocean flexitarianism - which encourages consuming foods found under the sea, including algae and seaweed. Harvey's research is hoping to draw attention to microalgae as a renewable, sustainable and nutritious food source for generations to come.

From an environmental perspective it makes sense. Algae consume carbon dioxide and use solar energy, so they don't have be grown using with high-performance energy systems. In addition they grow in saltwater, which humans cannot drink.

“About 70% of the Earth is covered with water and the ocean is about 98% of that,” says Harvey. “Inevitably we're going to be looking at the water to see whether we can get more food from there.

"If we just dive into the ocean to feed all those people, if we then turn to the ocean to [only] eat the carnivores, we’ll then mess up the ocean. That’s why it’s incredibly important to get more people to grips with eating algae, the vegetables, at the bottom of the ocean."

Ocean flexitarianism is incredibly healthy. For example, one of the nutritional benefits of fish comes from omega 3 - which is originally found in algae. The fish consume the algae and we consume the fish – eating it straight from the source cuts out a whole link in the foodchain. Plus, just one tablespoon of spirulina (blue-green algae) provides four grammes of protein, along with healthy doses of calcium, iron, magnesium and potassium.

So why hasn't ocean flexitarianism taken off sooner? Most types of algae are not legally recognised as food in Europe. While it has been consumed in Asia for centuries, in Europe it’s got to pass the 'novel food' categorisation - foods which were not widely consumed by people in the UK or European Union before May 1997.

But attitudes are changing all the time.

“There’s a big move amongst young [people] who want to have healthy lifestyles, who want to move to algae; a lot of work is now showing people are much more receptive than they used to be.”