We have a complex relationship with our oceans. At once they are a source of sustenance, food security and income, yet also an infinite repository for our waste.

This dichotomy has now reached a head as our oceans hit saturation point. We need to change our relationship with the sea. And we need to start by identifying who is the “we”. Those most responsible for the state of the world’s oceans are largely the producers and consumers in the G7 countries – who account for almost 50% of global GDP – and the burgeoning middle classes elsewhere. Just thirteen companies – mainly based in G7 countries or Europe – control up to 40% of the largest and most valuable fish stocks, according to recent research from the Stockholm Resilience Centre.

Going into the G7 meeting, a group of independent scientific organizations published a report outlining the interconnected challenges facing the oceans, which ultimately affect the global economy.

1. Plastic pollution. A recent report from the Ellen MacArthur Foundation calculated that by 2050 there will be more plastic in the oceans than fish, on current trajectories. But we simply don’t have enough information about where it is distributed, or its impacts.

Image: Ellen MacArthur Foundation

2. Deep-sea mining. Our computers, mobile phones and other technologies increasingly rely on rare earth elements such as europium, used as a red phosphor in LEDs, or neodymium used in hard disks and electric motor magnets. They are not as rare as they sound, the majority of rare earths are mined in China and shipped elsewhere. Mining companies are now scanning the deep sea for new sources of rare earths and other resources. But deep-sea ecosystems are very poorly understood and unintended consequences of human actions now often have a rapid global impact.

3. Ocean acidification. The world’s leading experts on ocean acidification met this month in Tasmania to discuss the latest research on the subject. Rising atmospheric carbon dioxide – the cause of ocean acidification – is occurring faster than it has in at least 66 million years. Combined with rising ocean temperatures and de-oxygenation, some marine ecosystems are going to struggle to survive, particularly corals and any marine creature with a shell. The only way to halt ocean acidification is to stop carbon dioxide emissions.

Image: Ocean Acidification Summary for Policmakers (IGBP, SCOR, UNESCO-IOC)

4. Ocean warming. The oceans have absorbed 10 times more heat than the atmosphere due to our increasing greenhouse gas emissions. This has big implications for extreme weather and climate variation over decades.

Image: Climate Central, NOAA, IPCC

5. De-oxygenation. An under reported aspect of climate change is how it affects oxygen in the oceans – oxygen is essential for marine life. Less oxygen is reaching down to mid depths from the surface due to rising temperatures, causing less mixing of waters at different depths. Along with sewage and fertilisers swamping coastal zones, this is causing expanding “ocean dead zones”.

6. Biodiversity loss. The Great Barrier Reef – one of the most diverse ecosystems on the planet – is in the midst of a crisis. A combination of threats, predominantly rising ocean temperatures, has caused alarming coral bleaching across vast swathes of the reef in 2015 and 2016. As of April, 93% of the reef has been bleached.

7. Marine ecosystem degradation. About 30-35% of critical marine habitats have been overused or destroyed. The health of the oceans is so perilous the oceans have been awarded their own Sustainable Development Goal.

The issues described above are all interconnected. We need a global approach to marine conservation. Covering 70% of the Earth’s surface and given the state of ocean ecosystems and fish stocks, nations need to collaborate scientifically and create better networks for research coordination. This is why Future Earth is establishing an Oceans Knowledge Action Network. We need to create a coordinated research agenda that links directly with policy needs. Future Earth calls on the support of G7 countries to develop a global innovation engine for marine stewardship.