How healthy oceans can help in the fight against climate change

From a climate point of view, protecting the oceans is like building solar panels and taking cars off the road. Let’s explore how the oceans and climate change are connected.

For many people, climate change conjures images of traffic-choked cities and power station chimneys, or bedraggled polar bears and oil spills.

But we often forget about the enormous power of natural systems like forests and oceans that help keep the climate stable – and that means we don’t look after them as well as we should. 

Whether we choose to protect or plunder the oceans will go a long way to deciding how climate change plays out, so let’s dive in and find out how it’s all connected.

The ocean soaks up carbon

Microscopic marine plants guzzle CO₂

Healthy oceans are amazingly good at taking carbon dioxide out of the air and locking it away in the depths. This process starts when tiny floating plants called phytoplankton suck carbon dioxide out of the air as they grow.

As small animals eat the phytoplankton, and other animals (like whales) eat those animals in turn, the carbon moves through the food chain until an animal dies and sinks to the bottom of the sea.

Although they’re invisible to the naked eye, phytoplankton have strength in numbers. Globally, they absorb billions of tonnes of CO2 Carbon dioxide, also known as CO₂, is the main greenhouse gas responsible for climate change each year – that’s a huge slice of our emissions cancelled out, all thanks to the oceans. And because healthy oceans support more life, creating ocean sanctuaries can help to maximise this carbon-busting effect.

CO₂ dissolves into seawater

But that’s just the start. Under certain conditions, CO2 naturally dissolves into seawater, and is pulled down to the depths by ocean currents, keeping it out of the atmosphere for the long term. 

Because this process happens slowly and over a huge area, its effect is harder to measure than the surface-dwelling phytoplankton’s hard work. And because there’s already too much carbon in the atmosphere, it causes problems for ocean life by making seawater more acidic, so we shouldn’t be too quick to celebrate it. But there’s no question that it’s locking away a huge amount of CO₂ that would otherwise be causing trouble up in the atmosphere. 

It’s a powerful example of how the climate and oceans relationship is a two-way street: tackling climate change is good for the oceans, and protecting the oceans is good for the climate.

Without these currents, and the phytoplankton’s carbon-munching prowess, the world would be uninhabitably hot. But we can’t take their help for granted – if the oceans’ natural systems breaks down far enough (and we’ve already pushed them way too close to the edge), they’ll stop storing carbon and start releasing it, at which point we’ll be in all kinds of trouble.

Oceans store extra heat from global warming

The oceans absorb huge amounts of heat from the atmosphere, making the land much cooler than it would be otherwise. Scientists think that of all the extra heat generated by climate change, more than 90% has been absorbed by the oceans. 

That’s spared humans a huge amount of suffering through avoided droughts and heatwaves, but it can’t go on forever – and already it comes at a cost. Adding such an enormous amount of heat and carbon to the ocean system is already hurting sea creatures, supercharging storms, destroying natural wonders like the Great Barrier Reef, and messing up other crucial life-support systems like currents. 

And because water expands as it warms up, more heat means rising sea levels, putting low-lying islands and coastal cities in danger. 

Climate change gives us even more reasons to protect the oceans

Lots of us are motivated to protect the oceans because we care about whales, turtles, dolphins and other wildlife – and of course that’s a good enough reason by itself. But knowing how much the oceans do to keep our climate stable makes this work we’re doing together even more important.

Like nearly everything to do with the environment, the story of oceans and climate change is full of connections and overlaps – the longer you look at each issue, the more they blur together. But the moral of the story is clear. To protect the oceans, we need to tackle climate change. And to tackle climate change, we need to protect the oceans. 

Let’s get to work.

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