The Government must change its “out of sight, out of mind” attitude to the seas and take the lead on plastic, pollution and ocean protection, MPs have urged.

Oceans are highly threatened by climate change, over-fishing and pollution, and the UK should push for a “Paris Agreement for the sea” – similar to the international deal secured to tackle global warming – to protect them.

In a report on sustainable seas, the parliamentary Environmental Audit Committee warned “we are treating our seas as a sewer”, with 80% of marine pollution coming from land through rivers, sewers and drains.

That includes plastic litter, untreated sewage, fertilisers and heavy metals, the MPs warned.

Oceans are also threatened by climate change, with temperature rises of 2C above pre-industrial levels set to destroy almost all the world’s coral reefs and significantly harm fish stocks and other wildlife.

Overfishing and other exploitation of marine resources such as deep sea mining also threaten the seas.

Our children deserve to experience the wonders of the ocean but climate change poses a triple whammy of threats from ocean warming, deoxygenation and acidification, which are decimating marine life. We have to stop treating our seas as a sewer. Plastics, chemicals, and sewage are choking our oceans, polluting our water and harming every ocean species from plankton to polar bears. Chair Mary Creagh MP

And she warned: “The Government’s ‘out of sight, out of mind’ attitude on the seas must change.

“We are calling on the Government to push for the creation of a legally-binding ‘Paris Agreement for the Sea’ to protect the world’s oceans.”

Including its overseas territories, the UK has jurisdiction over more than 6.8 million square kilometres (2.6 million square miles) of ocean, and the Government should take a lead on protecting marine resources, the MPs said.

The committee called for the Government to set out its plans to meet the aim of the Paris Agreement to limit warming to 1.5C, including setting a net-zero emissions target by 2050 at the very latest to halt greenhouse gas pollution.

It said more needs to be done to prevent pollution and waste reaching the oceans at home and by stopping exports of rubbish to countries where they are not properly recycled.

It called for ministers to bring forward their current goal to phase out avoidable plastic waste by 2042, extend rules that make manufacturers pay for disposal or recycling of packaging and products and speed up bringing in a deposit return scheme for bottles and cans.

80% Percentage of marine pollution coming from land through rivers, sewers and drains

The Environmental Audit Committee also warned the current approach to marine conservation in UK waters was not working, with too many harmful activities still taking place across too wide an area.

The Overseas Territories blue belt programme has “bold ambitions” to protect four million square kilometres of sea, but not all areas which have been designated meet international best practice guidelines.

The Government should support a legally-binding, international “Paris Agreement for the Sea” and the establishment of a new global oversight body for the oceans, to bring in sufficient protection for the ocean, the MPs said.

A Government spokeswoman said: “The UK is already a global leader in protecting our seas and oceans.

“We have recently proposed 41 new Marine Conservation zones, led calls to protect 30% of the world’s oceans by 2030, and we are going further and faster to tackle the plastic that harms marine life with our ambitious Resources and Waste Strategy.

“We know there is more to do, and we will soon publish an International Ocean Strategy to drive global action to conserve the world’s oceans.”