The world is facing a climate crisis that threatens the survival of millions of species, including humans. The impacts of global warming are already being felt in the form of extreme weather events, sea level rise, melting ice caps, and biodiversity loss.
To avoid the worst-case scenarios, we need to take urgent and ambitious action to reduce greenhouse gas emissions and enhance the resilience of natural systems.
One of the key actions that can help us achieve this goal is often overlooked or ignored in the mainstream climate discourse: halting overfishing.
Overfishing is the practice of catching more fish than the ocean can replenish, leading to the depletion of fish stocks and the disruption of marine ecosystems.
Overfishing not only jeopardizes the food security and livelihoods of millions of people who depend on fisheries, but also undermines the ocean's ability to regulate the climate and support life on Earth.
In this article, we will explore how stopping overfishing is a win-win solution for enhancing ocean vitality, bolstering climate robustness, and securing sustainable livelihoods.
The Unseen Connection
DOMINIQUE FAGET/AFP via Getty Images
The ocean is a vital ally in the fight against climate change. It absorbs about a quarter of the carbon dioxide emitted by human activities, and produces more than half of the oxygen we breathe.
It also regulates the global temperature and weather patterns, and provides a home for countless species of plants and animals.
However, the ocean is under threat from overfishing, which reduces its capacity to perform these essential functions. Overfishing affects the ocean's carbon cycle, which is the process by which carbon is exchanged between the ocean, the atmosphere, and living organisms.
By removing large amounts of fish and other marine life from the ocean, overfishing alters the balance of the carbon cycle and releases more carbon dioxide into the atmosphere.
According to a study published in the journal Science, overfishing has reduced the ocean's carbon storage by an estimated 1.5 billion tons since 1950, equivalent to the annual emissions of 476 million cars.
The study also found that restoring fish populations to their optimal levels could increase the ocean's carbon storage by 10%, or 205 million tons per year, equivalent to the annual emissions of 63 million cars.
Another way that overfishing affects the climate is by disrupting the ocean's food web, which is the network of interactions among different species in the marine ecosystem.
By removing the top predators and herbivores from the ocean, overfishing alters the balance of the food web and affects the abundance and diversity of other organisms.
For example, overfishing of sharks, tuna, and other large fish can lead to the proliferation of smaller fish, jellyfish, and algae, which have different impacts on the ocean's biogeochemistry and biodiversity.
A study published in the journal Nature Climate Change showed that overfishing of large fish can reduce the ocean's production of dimethyl sulfide (DMS), a compound that helps form clouds and reflects sunlight back into space.
The study estimated that overfishing of large fish has reduced the ocean's DMS emissions by 19%, or 3.5 teragrams per year, equivalent to the annual emissions of 875 million cars.
The study also suggested that restoring large fish populations could increase the ocean's DMS emissions by 10%, or 1.8 teragrams per year, equivalent to the annual emissions of 450 million cars.
Halting overfishing is not only a necessity, but also a benefit for the ocean, the climate, and ourselves. By allowing fish stocks to recover and marine ecosystems to restore, we can enhance the ocean's health and resilience, and reap the rewards of its services and resources.
One of the benefits of halting overfishing is the increase in fish biomass, which is the total weight of fish in the ocean. According to a study published in the journal Proceedings of the National Academy of Sciences, ending overfishing could increase global fish biomass by 56%, or 5 billion tons, within a decade.
This would provide more food and income for millions of people who rely on fisheries, especially in developing countries where fish is a major source of protein and nutrition.
Another benefit of halting overfishing is the improvement in marine biodiversity, which is the variety of life in the ocean. According to a study published in the journal Nature, ending overfishing could increase global marine biodiversity by 36%, or 4.1 million species, within a decade.
This would enhance the ocean's resilience to environmental changes, and preserve the genetic diversity and evolutionary potential of marine life.
A third benefit of halting overfishing is the reduction in greenhouse gas emissions, which are the main drivers of climate change.
According to a study published in the journal Nature, ending overfishing could reduce global carbon dioxide emissions by 6%, or 1.5 gigatons, per year.
This would contribute to the global efforts to limit the rise in global temperature to 1.5°C above pre-industrial levels, as agreed by the Paris Agreement.
