“The cause is simply to save humanity from humanity. The solution is to learn to live within the biosphere instead of dominating it.” – Paul Watson (Captain, Ocean Activist – founder of Sea Shepherd)

Overfishing and fishing slavery in south east asia
Each light is a fishing boat. Every night, every signle day.

The saying goes: “there’s plenty more fish in the sea.” Well, this saying is outdated! There’s actually not much left. Not so long ago, we thought that the ocean could replenish whatever we take from it. After all, the oceans are huge! Now we know that that is not the case. For fishing to be sustainable, we need to allow enough time for new ones to be born so the population can be maintained. The reverse is happening. We have taken more than the ocean ‘produces’, and we’re taking fish faster than they can reproduce. It’s called overfishing.

Overfishing has wiped out 90% of the ocean’s large top-predators, like sharks, tunas, cod, and groupers. And we need the big fish in the ocean because they eat the weaker ones. They prevent the ‘jenga’ from collapsing. The big fish that are still out there weigh 50% or less than they did 50 years ago. The average weight of a swordfish caught today is 45 Kilos. In the 60’s this was 130 kilos (1). Of all fish species, 52% is fully exploited, 17% is overexploited, and 7% is depleted. Common seafood choices such as tuna, shrimp, and salmon are among the worst affected. (2) I don’t want to withhold the good news from you: a whopping 1% of species are recovering from depletion!

The problem is not just the fish we’re taking; the problem is also how we’re taking it. We have advanced and crazy destructive technologies these days to find and catch any size of fish. Modern fishing techniques destroy habitats, damage ocean floors, and wipe out species. Most devastating are the fishing trawlers, which literally scrape the sea floor taking everything along with it. It’s like wanting to pick a flower by bulldozing the whole garden! How can the next flower flourish? Another fishing method that does more harm than good is ‘longlining.’ This method involves throwing out a long line with dozens of hooks. The fisherman aims for tuna, but in the process dolphins, sharks and even seabirds are also caught. This is called ‘bycatch.’

At some fisheries, for every kilo of fish that can be sold at the market, ten more kilos are thrown back, dead or half-alive, as bycatch! This is sorted out offshore so the fleet can be out at sea longer, go further, and catch more of what the market demands. It is estimated that global bycatch is 40% of the world’s total fish catch, with fisheries throwing back more than 28 million tons of non-targeted fish every year. 28 million tons (3). That’s comparable to the content of 28000 Olympic swimming pools full of dead fish that don’t qualify for our appetite. It makes bycatch on of the largest threats to maintaining healthy fish populations.

Despite the scooping, seafood consumption is rising because of diet shifts and population increase. Bluefin tuna, swordfish, and shark are still on restaurant menus. And since it’s called ‘fish of the day’, we think it’s fresh, local, healthy and acceptable. Food advice around the world recommends eating fish because of the omega health benefits. Fish are even squeezed to create fish oil pills. The Dutch ‘Voedselcentrum’ (Food Advisory institution) recommends people to consume one portion of fish per week (4). That means 17 million dead fish each week for a country that’s not dependent on fish for survival. What only a few know is that the healthy omegas originate in sea algae and weeds, of which almost all are edible.

People currently most affected are the ones that need fish as a food source the most. In the developing world, especially on the islands, fish is vital as a food source. There is simply not enough available land to produce for agriculture. Yet only fewer and fewer fisherman can obtain a living from fishing. With fewer fish in the ocean, there is less to catch for the local fisherman, less to see for divers, and less business for dive tour operators. When the ocean ecosystem collapses, humans go too. It might sound like a distant reality, but it’s not! If the current rate of exploitation is maintained, the ocean will be empty in 2048! (5)

Check for a live map of fishing vessels (only those trackable on the AIS!), to see for yourself the insane number of commercial fishing boats out there. Taking them is still possible because fishery management is practically non-existent at sea. It’s hard to measure, but there are numbers out that between 30 % and 70% of fish is caught illegally!

Fisherman are getting desperate to sustain a living, catching more and younger fish than they are supposed to, or fishing in prohibited areas.

Caption: Local fishing in Turkey. The local fishing method here on the Turkish turquoise coast. The fishermen set out a net in a sort of S-shape in the bay. They let it settle and then close it and drag it on their boats with a winch. Ten years ago, they could catch 50kg of fish with this. Today, they are lucky if they can catch 5kg! That’s nothing. They can’t live from it anymore. Now, the fishermen have diversified their livelihood and opened a lovely guesthouse in this beautiful bay. It’s wonderful for them and positive for the ocean! They can still eat fish now and then but are no longer dependent on it. They’re happy, and it hopefully gives the fish some time to rejuvenate.

What about farmed fish? Aquaculture, or fish farming, is a fishing method that is overtaking wild-caught fish. A solution? It’s like chicken farms. It might be more productive and quicker in volume but with it comes disease, antibiotics and pollution. Fish farms destroy surrounding habitats and mangrove forests in the process. Farmed fish are fed all sorts of fish and lots of it (but also meat!), which puts pressure on wild fish stocks. Fish like salmon, tuna, grouper are carnivores and need to be fed fish to be healthy. Farming fish in a closed space where waste is controlled, and there is little chance for fish to escape, seems better, but other challenges exist in managing the water quality for the health of the fish and the surrounding environment.

While governments debate fish quotas and ‘sustainable’ practices, and chefs debate which fish they can still “sustainably” cook, fish are continually taken without considering how much is left. Globally, we need to reduce our fishing efforts and fish consumption. Commercial fishing practices should all be banned. As long as we keep demanding, businessmen keep finding a way to supply. Action must be taken at global, national, local and individual levels. 

“The most important thing we take from the ocean is our existence.” – Sylvia Earle

  1. One World, One Ocean, One Mission. Anderson, T. L. 1, Canada : MacEwan University, 2013, Earth Common Journal, Vol. 3.
  2. United Nations Food and Agriculture Organization (FAO). General situation of world fish stocks. [Online]
  3. Kaledjian, A., Brogan, G., Lowell, B., Warrenchuk, J., Enticknap, B., Shester, G., … Cano- Stucco, D. Wasted catch: Unsolved problems in U.S. fisheries. s.l. : OCEANA, 2014.
  4. Voedingscentrum. Voedingscentrum. Vis. [Online] 2017.
  5. Impacts of Biodiversity Loss on Ocean Ecosystem Services. Worm, Boris, et al. 5800, 2006, Science, Vol. 314, pp. 787-790.

Great attention gets paid to rainforests because of the diversity of life there. Diversity in the oceans is even greater.” – Sylvia Earle

What is biodiversity change? Two words: Bio and Diversity. Bios comes from the Greek and means ‘life’. Biodiversity is a variety of life. Biosiversity sustains life in the sea. To have a healthy fish population there needs to be a healthy predator population. Predators prey on the weak and sick, keeping it all in balance. But the diversity is changing. Rapidly! As humans, we are not a healthy predator anymore. We have become more like monsters, interfering with the system like we’re the last generation on earth.

Climate change, ocean acidification and plastic pollution all make it harder and harder for marine life to thrive. We speed up the degradation process with fertilisers, chemicals, pesticides, herbicides, sewage, oil, plastics running down from land, and nuclear disasters. This results into ‘dead zones.’which are zones in the ocean where no life exists at all anymore due to a lack of oxygen.

A 2017 published study by the Tropical Research Institute found that coral reefs are associated with more than half of the known tropical dead zones worldwide, concluding that the risk of dead-zone to reefs has been severely underestimated. The same study estimates the number of dead zones far greater (441 in the tropics, and 447 outside the tropics), than previous estimates (1).

Coral reefs are complex underwater ecosystems. Reefs are the “rainforests of the sea,” and home to many living beings. Half of the shallow coral reefs globally are gone or in a serious state of decline. In the Caribbean, 80% of the reefs are already believed to be dead. One in every eight birds is in danger, one in every four mammals, and one in every three amphibians. Seal populations are now less than 10% of what they once were in the North Atlantic 500 years ago (2).

With fewer species, the greater the challenge becomes to maintain a healthy ocean, food security and the health of everyone on earth. It’s a bit like the game Jenga, where the aim of the game is to make a tower as high as you can (more money and appetite satisfaction). You take a block (a fish species) out of the bottom foundation (the ecosystem) and put in on the top of the tower (our appetite). We can only do this so many times until the tower (the ecosystem) collapses. Fish species collapse when only a few fish are left and are not able to reproduce fast enough to replenish the population.

The primary cause of the changes in biodiversity is: overfishing. The next challenge to tackle!

26. Tropical dead zones and mass mortalities on coral reefs. Altieri, A. H., Harrison, S. B., Seemann, J., Collin, R., Diaz, R. J., & Knowlton, N. (2017). Tropical dead zones and mass mortalities on coral reefs. Proceedings of the National Academy of Sciences. 14, 2017, Proceedings of the National Academy of Sciences, Vol. 114, pp. 3660-3665.

27. Earle, Sylvia. A. The world is Blue: How our fate and the ocean’s are one. Washington : National Geographic, 2009.

What is Climate Change? What is happening? And what can you do?

Ocean Challenges

We hear about climate change, plastic pollution, over-fishing and many other challenges. Many things are happening, and they are all interconnected. But what is actually happening? What is Climate Change? Why does it matter for the ocean? And for us?

Local fishermen have trouble catching, corals don’t look as colourful as they used to, and waters aren’t as clear. For the last ten years, I have travelled the world, visiting every continent and sailing on every ocean (except Antarctica). I have walked on remote beaches on islands hundreds of miles from any mainland. I explore the bottom of the sea whenever I can. I’ve explored below the surface in Tonga in the middle of the South Pacific, in the Galapagos, the Mediterranean, East Africa, Australia and the Caribbean. Everywhere I get confronted with the same: man-made situations to the detriment of the ocean. Plastic is everywhere, coral reefs are bleaching, fishing lines discarded, and endangered fish are on the menu and in the supermarket. We are destroying our planet, and we don’t realise it. Most of us only see coastlines and water surface, but when you are out, on, or underneath the ocean, you are constantly confronted with the damage we collectively are making.

what is climate change

I am not a scientist, but I explore, observe and learn every day. My ocean explorations have shown me the tsunami of challenges our oceans are facing.  My nephew is almost two now. I’m curious about what the ocean will be like when he starts snorkelling, and once he has kids. Experience and understanding are keys to action. In this post, I address what is Climate Change to help you understand what’s going on and what you can do to act. 

what is climate change

What is happening with Climate Change? | Palmtrees in Tonga

A brief intro on Climate Change

2016 has been recorded as the hottest year in human history. Since 2001 we have had 16 of the 17 warmest years recorded (1). A few degrees’ change may not seem like much, but when we take the average on earth, things change. We can already see the changes happening: wildfires, droughts, extreme rainfall, super-hot days, super cold days, and tropical storm development outside ‘the season.’ Weather patterns have never changed at such a rapid pace as we see today. It’s called Climate Change. And it’s not a distant reality anymore.

It’s hard to get a grasp on what is climate change since for most of us, it doesn’t directly affect us much (yet!). Yet, islanders, farmers, and fisherman have already experienced the consequences first-hand. When I was a kid, building snowmen and ice skating were guaranteed in winter in The Netherlands. Now we walk around in a T-shirt at Christmas time. While I’m typing this in Grenada, in the Caribbean the biggest storm surge is taking the coastline away. Locals have never seen the water reach this level before! In Tonga, the locals told me they already have had islands disappearing. The North-West passage, which used to be the most challenging passage where ships got stuck with the ice around them, is even opening up as a cruising ground.

How does climate change happen?

The atmosphere plays a fundamental role in the regulation of the climate. During the day, our planet warms up in the sunlight. At night, it cools, and the heat absorbed during the day goes back into the atmosphere. Some of the heat goes into space, but some of the heat is trapped by so called ‘greenhouse gases’, which includes Carbon Dioxide (CO2) and Methane, in the atmosphere. This has provided our planet with a consistent temperature and has made life on earth possible.

By nature, our planet produces and processes CO2. Plants, above and below the surface, take in CO2, and convert it into Oxygen. Animals, including us humans, breathe in the oxygen and breathe out carbon dioxide to live and thrive. What is now happening is that too much greenhouse gases (like CO2) are released into the air. More gases are trapped, and earth becomes warmer and warmer. We’re messing with the balance by adding more CO2 (by burning fossils fuels like oil, coal and gas) and removing what the planet needs to absorb CO2 (trees, seagrass, phytoplankton). It’s a double-edged sword! It makes it difficult for marine life, but also for us humans to adapt.

The changes in nature are not happening as a cycle of nature. They are man-made. We drive cars, browse the internet, eat meat, take airplanes, make babies, and use all sorts of products coming from the factories burning fossil fuels like there’s no tomorrow. We burn fossil fuels to create energy to make things, eat things, and move ourselves around. The biggest CO2 emissions come from agriculture and deforestation (2). Waste products from the creation process include carbon dioxide (CO2) and methane (another gas). Some of it is seen, like that exhaust you see when driving by a factory, but some of it is unseen.

Why is climate change a problem for the ocean and for us?

As long as CO2 levels continue to increase, so will the temperature. Sea ice and glaciers are melting around the world, causing sea levels to rise. As the oceans become warmer, the water expands, making the sea levels rise even faster. Less ice also means warmer oceans since less sunlight is reflected back into the atmosphere. With warming oceans, there is less circulation of warm and cold water, bringing fewer nutrients to the surface for plankton to eat. With Phytoplankton being of huge importance for absorbing carbon and producing oxygen, sea temperature rise disrupts this process. Some fish species are already going deeper. Fish and plankton move toward the poles for colder water with more nutrition near the sunny surface where they thrive the best.

Not only the temperature upsets the balance. When the ocean absorbs CO2 from the atmosphere, a chemical reaction occurs that makes the water more acidic. This process is called Ocean Acidification. For millions of years, the acidity level in the oceans has been stable. This steady pH balance (a numeric indicator of alkalinity or acidity) created a rich and flourishing marine life. Now, with our demand for fossil fuels and accordingly more CO2 out there, we have managed to change the pH in the ocean.

Warming and acidity of the ocean affect reefs, marine life, shellfish and Phytoplankton. If it gets out of balance to the point where Phytoplankton can’t survive, then other fish further up in the food chain can’t either. Plankton has already decreased by 40% over the last 50 years (3).

Islands on the forefront of climate change impacts | Vava’u Tonga


How much CO2 can our earth deal with?

At present rates, carbon dioxide is expected to reach 500ppm (parts per million) by 2050. The last time CO2 levels were this high, humans did not exist. Scientists say that CO2 levels this high would cause extreme weather changes that would endanger food supply, cause major mass migrations, species of plankton will be wiped out, and forests will be destroyed through droughts and fires (4).

To better understand the problem of CO2 in our oceans, let’s compare it with the carbon cycle in our bodies. It kind of works the same. We breathe in oxygen to convert nutrients into energy. A waste by-product of this process is CO2, which our lungs normally breath out. The more CO2 in the blood, the more acidic the blood is. As humans, we can also only tolerate so much CO2. If our blood pH levels become too acidic, because of consuming too many acidic foods and drinks like coffee, alcohol, tea or meat, this can lead to disease. We can balance it by eating alkaline fruits and veggies to stay healthy.

With freediving (breath hold diving), I don’t want to reach the surface because I need more oxygen. Rather, I need to go to the surface because my body gets sensitive to the acidic pH of my blood and needs to release CO2! What if it cannot go anywhere? It will disturb the functions in every cell of my body.

Minimising the stress on our bodies with pure foods and proper breathing keeps us healthy. The same must be done to keep our oceans healthy. We must minimise the acidic load on the lungs of our planet, the oceans, and keep the oceans in balance to neutralise the acids. In the oceans however, we’re not balancing it, this results in diminishing the health of the ocean. What if the CO2 in the atmosphere cannot go anywhere? It will disturb functions of life in every layer of the ecosystem.

I hope this post has helped to understand what is climate change and why it’s so important. We need to proactively tackle climate change, now! Shifting away from fossil fuels, adopting to simpler and less polluting lifestyles, and renewable energy sources like wind, sun, tides and certain biofuels (not all!) are critical in order to avoid climate change getting worse. It’s really urgent! 

So what can you do?

Simplify, minimize, consume less, rethink, and explore! Read more on what you can do here.

This blogpost on what is Climate Change is a snippet from the book Ocean Nomad: How to travel across the Atlantic by Sailboat. By experiencing the ocean first hand on a boat, you will be amazed by its beauty, gain a deep respect for its power, and also see its decline. Learn how to hitchhike on a sailboat and explore the ocean first hand, why the ocean is so important, which challenges we’re facing and above all how you can make a difference for a healthier ocean in book Ocean Nomad.


  1. NASA. NOAA Data Show 2016 Warmest Year on Record Globally. National Aeronautics and Space Administration Goddard Institute for Space Studies. 2017.
  2. IPCC (Intergovernmental Panel on Climate Change). Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment. New York : Cambridge University Press., 2014.
  3. Global phytoplankton decline over the past century. Boyce, D. G., Lewis, M.R. & Worm, B. 2010, Nature, Vol. 466, pp. 591–596. 
  4. Spratt, D. What would 3 degrees mean? 2010. 
  5. Oppenlander, Richard. Biodiversity and Food Choice: A Clarification. C fortably Unaware. 2012. biodiversity-and-food-choice-a-clarification/
  6. Jusková, I. Thesis Study. What’s in your carbon foodprint? Isabela Jusko. 2017.
  7. Cowspiracy. The Facts. [Online] Everaert, C. (Executive producer), Soeters, K., & Zwanikken, G. (Directors).
  8. Meat the truth [Documentary]. Alalena Media Productions., 2008.