(CNN) There are over 150 million metric tons of plastics in our oceans.

Each year, an additional 8 million are added -- the equivalent of a truckload every minute, according to the World Economic Forum

At this rate, by 2050 there will be more plastic than fish in our oceans by weight, the Ellen MacArthur Foundation estimates

Dame Ellen MacArthur made history in 2005 when she became the fastest solo sailor to circumnavigate the globe, and started the foundation in 2010 to support the idea of a "circular economy," which promotes renewable energy and waste reduction over the consumption of finite resources.

Now, in a joint venture with The Prince of Wales's International Sustainability Unit , she is launching a $2 million design competition to keep plastics out of the ocean.

"After 40 years of effort, globally only 14 percent of plastic packaging is collected for recycling, with one third escaping collection and ending up in the environment. If we want to change this, we must fundamentally rethink the way we make and use plastics," MacArthur said.

Recycling rates vary wildly from country to country, but a significant amount of consumer plastic ends up in landfills or is discarded into the environment and the waterways, where it can become deadly to marine life.

The prize is designed to keep these plastics as valuable materials in the economy, and out of the ocean.

It offers two challenges, each worth $1 million.

The first, called "Circular Design," will focus on small items such as wrappers, lids and sachets, which are hardly ever recycled because doing so is not economically viable. The winning idea will allow these products to still reach consumers, but without the current level of waste, ether by eliminating disposable packaging or by designing packaging that is easier to recycle.

The second challenge, "Circular Material," tackles layered packaging. Most plastic containers are made of several different layers which are fused together. This is efficient for food conservation, but terrible for recycling, as the components need to be separated to be recycled, and in some instances this is impossible or not economically viable. The challenge seeks a new type of design that uses alternative materials that can be recycled or composted.

The winners will be judged by a panel of academics, designers and scientists, and will get their prize in grants and visibility of their solutions to businesses and the public, including a year-long accelerator program.

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The prize is part of a larger, three-year initiative called " New Plastics Economy ," to build momentum towards a more sustainable plastics system.

"When you sail around the world on a boat, you have with you everything you need for your survival for three months," Ellen MacArthur told CNN's Isa Soares.

"And you realize what finite means, that finite resources are exactly he same on a boat as they are within our global economy - and we're using them up."