We already have all the conventions, treaties, declarations and agreements we need to take on ocean plastics.
The world is awash with enormous, difficult, complex problems. To name just a few: climate change, a terrifying rate of biodiversity loss, and nuclear weapons capable of terminating human existence. And now we have new one to face up to: the global scourge of marine plastic pollution.
But don't let despair get the better of you. There is good news. It took decades to negotiate the Climate Change Convention, its Kyoto Protocol and now the Paris Agreement, the Biodiversity Convention and the various nuclear arms limitation and test ban treaties, and for them to be ratified and enter into force.
But we already have all the conventions, treaties, declarations and agreements we need to take on ocean plastics. The litle known fact of the matter is, a plethora of international laws already make it illegal for states to allow their plastic waste to pollute our seas and oceans.
So while we have been slow to appreciate the enormity and gravity of the ocean plastic problem humanity has created, we enjoy a head start of ten to twenty years, compared to where we might expect to be. There's no need to spend decades negotiating and ratifying conventions. It has already happened. Instead we must get the laws we already have respected and upheld.
These laws include the United Nations Convention on the Law of the Sea (UNCLOS), which came into force in 1994 and requires states to "prevent, reduce and control pollution of the marine environment from any source", "to minimize to the fullest possible extent ... the release of toxic, harmful or noxious substances, especially those which are persistent, from land-based sources" and to "protect and preserve rare or fragile ecosystems as well as the habitat of depleted, threatened or endangered species and other forms of marine life."
And as a large and ever growing body of scientific evidence makes clear, that wording demands drastic reductions in the volumes of waste plastic generated by almost every one of the 167 signatory states.
There are also dozens of regional marine treaties, such as the OSPAR Convention, which applies to the North-East Atlantic. OSPAR requires its parties (including the UK) to "take all possible steps to prevent and eliminate pollution and shall take the necessary measures to protect the maritime area against the adverse effects of human activities so as to safeguard human health and to conserve marine ecosystems and, when practicable, restore marine areas which have been adversely affected."
These two are examples 'hard law', legally binding on all states that are members of the treaty. Sadly that does not mean they are easy to enforce. There is no policeman for international treaties, nor is there a prosecutor.
There are courts, including the International Court of Justice and the International Tribunal for the Law of the Seas. But only states that are parties to a treaty can bring cases to those courts. So that excludes you, me and environmental campaign groups.
Still, that does not put an end to the matter. It's entirely conceivable that a country whose environment, tourism and economy are being damaged by marine plastic pollution could seek redress in the courts.
It's unlikely to happen right away, but a small island state, acting as part of a wider coalition - the Association of Small Island States, until now mainly concerned with climate change, comes to mind - backed by NGOs - perhaps ClientEarth, Greenpeace, Birdlife International, WWF - might consider taking this this step.
More immediately, international law carries great moral force, and that is something campaigners can use to good effect. Citizens in almost every country on earth can remind their governments and politicians that they have signed up to legally binding treaties, and that to be in flagrant breach of the obligations so incurred is to bring national shame and dishonour.
We can ask ministers to explain how they plan to enter into compliance with their commitments. We can also demand that corporations set out their plans to support governments in the countries where they operate to fulfill their legal obligations.
More generally, the existence of so much international law transforms our position from that of supplicants begging governments to do the right thing, to that of empowered citizens demanding that governments and other entities comply with their legal obligations.
And as far as moral force is concerned, a host of solemn agreements and declarations negotiated at UN conferences and other authoritative fora do not fall far behind hard law - even if they are not legally binding.
These include the 1995 Washington Declaration on Protection of the Marine Environment from Land-based Activities, in which signatories state as their common goal the "sustained and effective action to deal with all land-based impacts upon the marine environment", including those resulting from litter.
It also contains very useful language calling on donors to support poorer countries in their efforts (Articles 9-12), for example by "encouraging and/or making available external financing, given that funding from domestic sources and mechanisms for the implementation of the Global Programme of Action by countries in need of assistance may be insufficient".
Millennnium Development Goal 14 even sets a date for significant improvements to be made, with states promising they will, "[b]y 2025, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution". That makes the UK government's 2042 target for the elimination of 'avoidable' plastic waste look tardy and complacent.
In short, the great body of international law applicable to marine plastic pollution, both hard and soft, is something that can be used very effectively by citizens, campaigners and environmentally concerned nations - or ideally all three acting together - to demand rapid and effective action by governments, development banks, United Nations agencies and corporations to keep our oceans alive, healthy and free from the plastic menace.
Now let's make it happen.
Oliver Tickell is a contributing editor at The Ecologist, and a former editor. He is the author of the report International Law and Marine Plastic Pollution: Holding Offenders Accountable which is published by Artists Project Earth (APE) under its Ocean Plastic Legal Initiative (OPLI). The report and additional information are available on the APE website.