Do Oceans Have the Potential To Reverse Climate Change?

15 September, 2021

A quick search about climate change, marine conservation or oceanic ecosystems is enough to tell us that the underwater environment is depleting much quicker than we had anticipated. Global warming has led to tremendous damage of the marine ecosystem and biodiversity loss has increased.


A study found that if the climate crisis goes unchecked, global temperature will rise by 4℃ in the next 80 years (by 2100). The thing with climate change is that small numbers, spaced over a considerable amount of time for a human’s life seem harmless and encourage ignorance towards the issue. But the crisis is imminent and pervasive. This 4℃ rise translates to about 15% of ecosystems facing an “abrupt exposure event”, where the species in these ecosystems will cross their threshold, go extinct and start a domino effect on ecosystem damage, which a hundred per cent, will be irreversible. Between 2000-2065, more species of plants and animals will go extinct than we lost in the last 65 million years.


Given the rise in oceanic temperatures and growing acidification, marine ecosystems will be the first. The Great Barrier Reef could be the first ecosystem to collapse within 20 years from now.


However, maintaining the temperature rise to less than 2℃, as set by the Paris agreement, will only expose 2% of ecosystems to the change. Mass scale urgent action taken by governments, industries and giant corporations is what can save catastrophic damage.


The problem with overfishing

Two of the major problems of the ocean are overfishing and acidification. This overgrazing, usually caused by unsustainable fishing management and increasing acidity threatens underwater ecosystems.


At the beginning of the year, a study found that only 37 of the 104 fish stocks in the UK are currently at a healthy size while 60% of them face the risk of collapse. This not only threatens those whose employments come from this sector but also brings in a possibility of a food crisis.


This study noted that majority of the UK’s ten most economically important fish stocks—including North Sea cod, North Sea herring, Southern North Sea crab, Eastern English Channel scallops and North East Atlantic blue whiting—are at a critically low level. Only North East Atlantic mackerel and West of Scotland Nephrops are being fished sustainably, owing to a few legislations.


The easy solution is to follow fishing regulations and curb the problem. After all, fishing rights have helped increase the red snapper population threefold since 2007, in the Gulf of Mexico. Ending overfishing has the potential to save the marine ecosystems—it protects marine food chains, reduces underwater habitat degeneration from indirect pressures from invasive fishing gears and pollutants and most importantly, cuts down CO2 emissions from the fishing sector by 50%.


Yet, overfishing continues to dry out fisheries across the world. A major challenge to these policies comes from nations whose fish stocks have depleted. Not only do they dispatch trawlers in international waters, they subsidise fishing and once done, it becomes difficult to take them away. Over the last few years, China has had the highest number of subsidies while the European Union, in 2018, gave out over $2 billion towards the same.


Given that oceans are self-sustaining ecosystems, they have immense potential for carbon capture and filtration. Protecting these ecosystems by maintaining a stable marine life—or leaving the big fish where they belong—leads to carbon sequestration. The ocean’s ability to capture carbon to clean the earth’s atmosphere makes it a valuable resource to help climate action.

Carbon capture as a solution to the climate crisis?


Ever since the industrial revolution, the oceans have been capturing large amounts of CO2 from the atmosphere and locking it into the deep sea. But the presence of carbon has severe consequences on marine ecosystems as it causes acidification of oceans, a major concern threat to life below water.


Latest studies find that oceans can hold four times the amount of CO2 than anticipated. Currently acting as the largest carbon sinks on the planet, they hold about 38,000 gigatons of carbon, much more than any rainforest. 


Interestingly, researchers propose a new potential solution to climate change that aims to shoot two birds with one stone. Exploring the potential of capturing carbon, ocean-based carbon removal approaches aim to reduce CO2 from the atmosphere while making sure that it does not increase acidification of the water, maintaining an underwater balance. 


The idea is to allow the oceans and coasts to absorb as much carbon from the atmosphere naturally as possible through planting mangroves, seaweeds, seagrasses and salt marshes, through photosynthesis. Or using the controversial idea of iron fertilisation that essentially bags on phytoplankton growth through the introduction of iron in the oceans. 


However, the fragility of ecosystems must not be overlooked. They are prone to risks of collapse even while implementing solutions to reverse climate change by causing chemical alterations at a large scale—disrupted pH or oxygen levels underwater, changes to currents and movement, etc. In the case of iron fertilisation, the process risks toxic algal blooms and unexpected chemical alterations, if not monitored closely.


Following the process of carbon capture, through a chemical approach called alkaline enhancement, researchers aim to convert carbon dioxide into bicarbonates by introducing different minerals—creating rocks out of pollution. Another approach aims to store carbon as dissolved bicarbonates by introducing electric waves into seawater. 


While these proposed approaches towards carbon sequestration seem like glistening light at the end of a tunnel, they are all experimental having been conducted on small areas. They certainly offer a cleaner and healthier atmosphere—over and underwater—if executed correctly, but the risks of failures with geo-engineering entire ecosystems are high. Another challenge to these approaches is in their execution. They are bound to have unpleasant impacts on local communities, require strong legal frameworks and precise engineering.

Concluding thoughts


It’s imperative for all communities to identify the need to take immediate climate action. While the cost of implementing preventive measures is high, the cost to clean up and reverse damage will be much higher. Carbon capture and removal approaches need effective and thorough research and strong government backing before approval and application to avoid permanent ecological damage. However, given the advancement of the crisis, such schemes may just be the only thing that can reverse it.

However, I have always maintained that nature can heal herself if given a chance – she already created the right conditions for our survival, and the intricacy of these processes is what we need to protect.

Check out these excellent videos from George Monbiot on How Whales Change Climate and How Wolves Change Rivers:




Newsletter Signup

Newsletter Signup

To keep up to date with our latest news and blog posts, please enter your details below.