These plagues are certainly real, but their severity is exaggerated through a feedback loop involving the spinning of research headlines to compete for media attention.
In an emotional article making waves on social media at the moment, yachtsman Ivan Macfadyen reports seeing no marine life at sea, only floating rubbish, while sailing across the Pacific. He concludes that "the ocean is broken".
I understand Ivan’s feelings, as I too have sailed tens of thousands of miles onboard research vessels and on my sailboat, enjoying the slow and silent pace of life propelled by wind and waves.
The two issues Macfadyen raises - overfishing and plastic pollution - are real problems. More than three-quarters of the oceans' fish stocks have been depleted, sometimes beyond recovery. The global tuna industry, particularly, is better portrayed as the War On Tuna than a fishery. And the world’s oceans are filled with large amounts of plastic debris, which are eaten or caught up in marine life or seabirds, or which break down into microscopic particles that are ingested and affect wildlife in ways we don’t yet know.
So yes, there are plenty of problems in the ocean. But it is not yet broken. I am increasingly upset about reports that say it is; we scientists are to some extent to blame, as we love being the bearer of bad news, composing an overly apocalyptic narrative.
Depicting the ocean as broken and suffering from a litany of plagues including climate change, hypoxia, eutrophication, ocean acidification, marine pests, spreading jellyfish blooms, and loss of valuable habitat, suggests a problem beyond repair.
This eventually deters society from engaging. These plagues are certainly real, but their severity is sometimes exaggerated through a feedback loop involving, among others, the spinning of research headlines to compete for media attention.
Let’s focus on Macfadyen’s evidence for a broken ocean: two snapshots of the Pacific, ten years apart, suggesting a depletion of marine life and huge plastic pollution.
The ocean is a dynamic ecosystem, which fluctuates broadly over time, from its physical and chemical properties to the abundance and distribution of fauna and flora. Such fluctuations can deceive the casual observer - to detect real change requires high quality data gleaned from systematic long term observations.
For instance, my co-workers and I analysed global changes in jellyfish populations, and found there is no basis to the claim that they are growing "plague". Instead, we found that jellyfish populations fluctuated over 20 year cycles, giving the misleading perception that the most recent rising phase of this cycle (roughly between late 1990s and late 2000s) was an unprecedented event.
Likewise, we also know that many changes portrayed as symptoms of a broken ocean, such as coral bleaching, outbreaks of invaders such as the crown of thorns starfish or toxic algae, may also largely represent symptoms of global oscillations that we do not yet fully understand and in which humans' actions play little or no role.
Separating the human impacts entwined in such natural fluctuations is a daunting task, so we should not be too quick to jump to conclusions and blame humans for all the changes we see around us. Our analysis showed that such fluctuations happened in the past, but very few scientists were watching and they lacked the channels, such as the internet, to share their results.
Soon after the earthquake and tsunami of March 2011 that triggered the Fukushima accident, NOAA published models that predicted how the huge amount of debris washed into the ocean by the power of the retreating waves would take three years to travel across the ocean and wash up sometime in 2014 on the beaches of California, Oregon and Washington in the US. Had Macfadyen checked NOAA’s web page, he’d have expected the garbage patch he encountered.
The tsunami was not caused by humans, so we should rein in our feelings of guilt about it. It does, however, provide a brutal exposure to the reality that we feverishly consume and dispose of too many, mostly plastic objects, many manufactured with harmful chemicals, that we use just for just a short while and then throw away.
What kind of fishing line did Macfadyen use in his first voyage, and what happened to it when he’d finished? What chemicals are in the anti-fouling paint for his boat’s hull? Likewise, how and where was the fish we consumed with our last meal captured? Did it come from a sustainable fishery or a sustainable aquaculture farm? Did we bother to ask if it was a certified product? Do we demand that this information be displayed to guide our choices as consumers?
Should we eat tuna, an apex predator at the top of the food chain, or should we settle for sardines, oysters and seaweed? Was that chicken we ate yesterday for dinner fed fishmeal? Do we drive a four-wheel drive car whose CO2 emissions will further acidify the oceans, or do we cycle, drive a hybrid or electric vehicle or catch a bus powered by biofuels?
Do rich, developed nations with among the world’s largest greenhouse gas footprints refuse to implement carbon taxes or emissions reduction strategies because we "cannot afford" them?
These questions are not easy ones to ask ourselves, but we confront our contradictions. We enjoy eating seafood, an essential component of a healthy diet. We know that fish stocks are over exploited, so developing aquaculture is the only avenue to sustainably meet the growing demands for seafood. But then we get upset if we can see an aquaculture farm off our coasts.
Responsible consumers will not break the ocean; those who choose to ignore the consequences of their day-to-day decisions as consumers will. The place where the struggle to save the oceans from breaking is fought everyday - not once every ten years - is at our local shops.
Professor Carlos M. Duarte is Director of the Oceans Institute at The University of Western Australia and Research Professor with the Spanish National Research Council (CSIC) at the Mediterranean Institute for Advanced Studies (IMEDEA) in Mallorca, Spain.
Carlos receives research funding from The EU Framework Program, the Spanish National Research Plan and the CSIRO, and he is affiliated with the Spanish National Council for Scientific Research (CSIC) and The University of Western Australia.
This article was originally published at The Conversation.