Imagine the ocean without fish. In a short while, it may take more imagination to remember a time when our oceans were teeming with life. Decades of destructive fishing practices has left us with rather precarious levels of fish stocks today, especially of large predatory fish such as bluefin tuna and cod, with serious implications for the rest of the marine food chain. The nefarious practice of (mostly illegal) bottom trawling has, in addition, destroyed hundreds of thousands of marine mammals, seabirds, sea turtles, sharks, and coral reefs. What is left is often barren waters.

Oceans cover 70% of our planet, most of it beyond the sight of our lands. Thus, while wildlife on land is often protected and trees and watersheds find a mention in conservation laws, it is easier to be disconnected with our ocean and its services in enabling life in all its forms. Home to 97% of life on earth, our oceans happen to be the real lungs of our planet as seaweed provides more than half of the oxygen we breathe. Our oceans and seas stabilise atmospheric temperature, regulate our water, carbon, nitrogen and oxygen cycles, and shape the earth’s chemistry. They act as climate regulators and are the reason anthropogenic climate change has not devastated the planet already. Over time, microbes in seawater have absorbed about 9% of all excess heat in the atmosphere due to human-induced greenhouse gas emissions and about 30% of all CO2 emissions from burning fossil fuels to date. Our oceans have time and again acted as a carbon “offset” system, a natural carbon sink, to draw down mankind’s systematic and heedless spewing of atmospheric emissions

Yet, beyond our visible eye, our oceans are suffering quietly. The ever-increasing CO2 emissions in our atmosphere globally directly impacts our oceans by increasing ocean acidification thereby impacting marine life, most notably organisms that form calcium carbonate such as corals and shellfish. It also increases the incidence of ocean heatwaves, and as the ocean expands due to warming this strains its ability to pull the extra heat absorbed on its surface away to its interiors. Warmer surface temperatures increase respiration rates which in turn lower oxygen concentrations in tropical seas where pockets of oxygen deficient zones have already been created, patches of water that can no longer support marine life. The implications of warming are not limited to the oceans alone, as fisheries affected due to climate change in turn impact humans that depend on fish for a living. Furthermore, fish and seafood are a staple food for one out of four people on the planet, and it is a pity that fish stocks are continuing to deplete due to both unsustainable fishing practices and human-induced climate change. Ensuring our long-term survival and wellbeing now depends crucially on how we manage our oceans and marine life today.

Ireland is not immune to the effects of climate change on our oceans. We are likely to experience more frequent and increasingly severe winter storms as well as see extra-tropical cyclones for the first time due to the North Atlantic Oscillation phenomenon. Just like many other coastal communities, Dublin Bay anglers have observed a depletion in fish catches. It is crucial therefore that we prioritise the health of our oceans. Apart from lowering our carbon emissions in industry and building practices and focusing on efficiency and better waste management, we must also protect at least 30% of our oceans from fishing and other activities via ‘no-take reserves’, giving them time to replenish and regenerate. Importantly, we must ban bottom trawling both locally and in the high seas for the simple reason that the more complete the food web is in our seas the higher will be their resilience to recover in the face of warming. The good news is that examples from Chagos Archipelago and other marine reserves from around the world have shown that our degraded seas can and do recover when protected, and in a decade reach near pristine levels of aquatic life.

The ecological benefits of caring for our oceans today will in time spill over to benefit coastal communities economically and socially and make for a healthier biosphere overall as local economies are boosted from better fishing and tourism revenues. As individuals, we can move to more plant-based diets. As coastal communities, we can be more vigilant about changes in our coastlines, and help research that aims to protect these. As engaged citizens, we can increase our own awareness of anthropogenic climate change, and collectively put pressure on our governments to redesign and improve governance in marine conservation, including helping to decentralise conservation efforts towards more community-led initiatives. As leaders, we can help re-direct funding and create new business models that take full account of ecosystem services, where coastal conservation is seen as an investment, and entered into in collaboration with local communities. As governments, we must end subsidization of fisheries on the scale that exists today, which in turn incentivises overfishing and unsustainable fishing practices. We can all help our oceans continue to thrive and protect us. Before we begin to create new carbon sinks and invest heavily in technology to capture CO2 from our oceans and our atmosphere, let us not ignore the natural life support systems that have already existed for millennia and thereby protect our own heart and lungs into the future.

Article written by Biosphere Social Influencer Sanghamitra Chattopadhyay Mukherjee (Sangha).
Octupus at Night by Sarah Tallon
Oldest Lobster in the Bay by Nigel Motyer
Stardust by Marco Salino
Seal Pup by Nigel Motyer