More than 70 percent of Earth’s surface is covered by ocean. But those life-giving waters are increasingly clogged with plastic waste — leftovers from consumer activity and commercial fishing that lump together in huge garbage patches and choke fish, birds and other marine life.

How to tackle a problem that’s growing fast? A new contest is looking to the public for creative solutions — and promises to pay handsomely for the most innovative ideas.

The newly launched Ocean Plastic Innovation Challenge is recruiting strategic thinkers to compete for a $500,000 prize and at least $1 million in investment dollars. The one-year competition seeks original ways to stem the tide of ocean plastic pollution and raise awareness of the problem.

The challenge is sponsored by National Geographic and Sky Ocean Ventures, an investment vehicle funded by the European entertainment company. Last year, the partnership launched Planet or Plastic? — an initiative aimed at provoking change around single-use plastics.

Something’s got to change, or ocean plastic pollution will become even more catastrophic. It’s on track to outweigh fish by 2050. The amount of plastic waste in oceans is expected to double by 2025. Ocean plastics are already affecting marine life, hurting people whose livelihoods depend on fishing and threatening human health.

The contest focuses on three paths to ocean plastic reduction: designing alternatives to today’s single-use plastics, figuring out how to tweak supply chains to reduce plastic waste, and using data visualization to spur awareness and action. Contestants can register in any of those three categories.

Registration is open. The submission deadline is June 11. Winners will be announced in December. And with $1.5 million in awards and investment — and the future of the planet at stake — there’s no time to lose.