Marine heatwaves - an ever growing threat?

Hi everyone,

So today we're talking about marine heatwaves. We all know about normal heatwaves, they come almost every summer and are either a blessing or a curse depending on where you live. But today we're talking about marine heatwaves. They are increasing rapidly and have become a commonly mentioned topic.

There are multiple definitions of marine heatwaves. Generally, they are considered a period of time with unusually high temperatures. Exactly how high and for how long changes depending on which definition you choose. The most common one definition is when the temperature is over the 90th percentile of the area's average seasonal temperature for at least 5 days in a row. For anyone who doesn't know what a percentile is, if you take a test and are at the 90th percentile then it means you are better than 90% of the people who took that test. So in our context, the temperature has to be higher than 90% of the seasonal temperatures measured in that area (normally over a 30 year period) for at least 5 days.

So what are the impacts of such an increase in temperature? Surprise surprise: marine heatwaves aren't exactly good for the environment. It is worth mentioning here, that marine heatwaves are natural occurances in the ocean temperature and have always been around. But the frequency and intensity of them is not natural. Both of these parameters have been rising rapidly in the last 100 years. Marine heatwaves can cause waters to reach temperature of 30°C, which is about the temperature of a warm bath. El Niño, a weather cycle that repeats about every 7 years, is shown to cause stronger heatwaves.

In the late 1990s, a marine heatwave intensified by El Niño lead to a reproductive failure and mass mortality in Galápagos sea lions and king penguins. Then, in 2011, the western coast of Australia was hit by a marine heatwave that caused the mass dieback of kelp forests and impacted ecosystems hundreds of kilometers further along the coast. An interesting phenomen was seen here, when several fish species changed their habitat and spread further towards the poles. This has been seen a couple time since in multiple species, sometimes the fish return once the waters have cooled, sometimes they stay in their new home and sometimes they die, either from new predators or a lack of food.
In 2014-2016, the northeastern Pacific saw mass mortality in seabirds as they failed to adapt to soaring temperatures. In 2017, there are reports of mass mortality affecting 40 coral reef fish species correlated with an increased risk of bacterial infection and harmful algal blooms, which produce toxins. And finally, in August 2020, a marine heatwave in the East China Sea caused a major typhoon in that area. The East China Sea rarely experiences typhoons and normally those that come in from the Pacific tend to die down, but this time the high surface temperatures caused a typhoon of Category 3.
There are some postives, mussels have been found to be able to change their heart rate so as to better deal with higher temperatures. This is just one example of how amazing and resilient nature can be.

So marine heatwaves are clearly a massive problem. As you can imagine, typhoons and collapsing fish populations are also a bit of a disaster for us. These marine heatwaves will only continue to become more frequent and more devastating as climate change warms up our oceans. We couldn't cover all of the aspects in this post so let us know what we missed in the comments. We hope this was a good introduction in this complex topic. Have a nice weekend!

Your Green World Blog Team💚

Sources:
https://www.nature.com/articles/s41612-023-00449-5
https://www.annualreviews.org/doi/10.1146/annurev-marine-032122-121437
https://en.wikipedia.org/wiki/Marine_heatwave
https://www.sciencedaily.com/releases/2023/09/230921105743.htm

Image:

Title image: This image is owned by a blog editor.
"Galapagos sea lion", owned by Darek Keats (on flickr.com), is licensed under CC BY 2.0.
"Baltic blooms", owned by European Space Agency (on flickr.com), is licensed under CC BY-SA 2.0.

Comments

Deforestation and why it’s a problem

Hi everyone, Welcome back to another post. Today we’ll be talking about deforestation and its impacts on our earth. Deforestation, the widespread clearance of natural forests, has been happening for thousands of years. One example is Western Europe, where, two millennia ago, 80% of the land was cloaked in dense forest cover. However, over time, a significant portion of this green expanse was sacrificed to create room for crops, livestock grazing, and as a source of fuel and building materials. Presently, a mere 34% of Western Europe retains its woodland. Today, the tropics deal with the brunt of deforestation. Activities such as mining, agriculture, road construction, and the establishment of vast cattle ranches drive the mass clearance of tropical rainforests. This results in the release of huge amounts of carbon dioxide into the atmosphere, exacerbating the global climate crisis. The consequences come in two waves: first, the reduced number of...

Evolution

Hi, So today, I am going to talk about evolution. We have mentioned this before in our Galapagos Ecosystem series but we’ve never gone over exactly what it is. So before Charles Darwin thought of his theory of evolution, the majority of people in Europe thought that all species were unrelated and that humans were not related to animals. This was mostly based on Christianity. Darwin studied hundreds of different species and on the Galápagos Islands , he first started to form his theory of evolution. Darwin's theory of evolution by natural selection, as it was later called, is best explained by the example of the giraffe. Let's assume that giraffes have short necks (as they did many centuries ago). Now a mother has two children. By chance, one has a slightly longer neck. This is a coincidence. As the giraffes feed on the lower leaves of the trees, these slower disappear. There aren't enough leaves for the giraffes. Thus the giraffe wi...

Beavers and their dams: what effects do they have?

Hi everyone, Today we're talking about beavers and their effects on the surrounding ecosystems and environments. 'Beaver' referres to two species in the genus Castor . They are found in North America, Europe and Asia and are the largest rodents in those places and the second largest rodents in the world. Beavers grow up to 80 cm long with a flat, paddle-shaped tail up to 45 cm. They have a small head, large incisor teeth and fur lined lips to avoid inhaling water while cutting and transporting branches underwater. They weigh 16-30kg and are nocturnal. Beavers live in streams, rivers, marshes, ponds and lakes where they construct dams. These have earned them the title 'ecosystem engineers' but we'll talk about that later. The dams are constructed with branches, sticks and rocks. They create a calm pool with a higher water level on one side. Beavers make their homes (lodges) in these calm pools. Beaver dams are both have bot...

Climate change: what is it and what's the problem

Hello, I've noticed that we are always mentioning climate change. Not only us blog editors but also politicians, activists and so on. The words climate change are bounced around in the media and probably in your households, but do you actually know what it is or how it works? I know that for a long time, I didn't know what it really meant. I hope that this post changes that. What is climate change and how does it work? The words climate change describe a slow shift in the earth's temperature and changes in the weather patterns. Having a single warm winter does not instantly mean climate change. Climate change happens over a long period of time. If you look at a temperature graph over the years, it doesn't go up in one day and then stay the same for another hundred years. It curves up slowly but steadily. This is a average temperature graph from 1880 to just after 2000. You can see how the temperature gradually gets warmer....

The Responsible Traveller by Karen Edwards || a practical guide to reducing your environmental and social impact // BOOK REVIEW

HI Everyone! Our January monthly post was a zero-waste challenge, but as we explained in our 2023 wrap up , this year we will be alternating a monthly challenge with a book review, of course related to the environment. This week, I'm going to share a recommendation for a fantastic book, all about how you can travel more sustainably and responsibly. I absolutely love travelling, but I'm also very aware of the impact it has on the world, and I am very keen to learn more about how I can further reduce my impact. That's why I bought this book around a year ago, and I've really enjoyed reading it and learning from it. This is a practical, small-format guide, sharing both basic information about the climate crisis and the impact of various travel activities, and how you can do your bit. It shares specific journeys that are more environmentally friendly options, for example long distance train journeys such as The Alaskan Railroad with its stunning alpine forests and wide ar...

April Top Tips: ten tips for environmentally friendly travel

Hi Everyone! We haven't been very present on the blog again recently but we are back today with ten top tips for environmentally friendly travel. Most forms of travel over long distances (unless you are willing to put in a lot of physical effort) use fossil fuels and are generally not good for our planet. So today we will be giving you a few tips which although won't mean that your travel is 100% planet friendly, will be a good start to doing as much as you can. Your Green World Blog Team💚 1. Use trains and boats rather than planes where possible Planes are awful for the environment. They are, however, extremely practical and so easy to use, cheap...It's hard to avoid them! They are so quick too so you don't have to spend as much time travelling. However, they are really bad for the environment. For example, you could fly once to Edinburgh from Heathrow for the same carbon dioxide levels as driving to Edinburgh 336 times! 2. Fly...

10 Animals on the edge of extinction, You did not know about no.1 - Yangtze Finless Porpoise

The first animal of this series is the Yangtze finless porpoise, a dolphin living in fresh water in southern China in the Yangtze river. It is one of the very few dolphins living in fresh water and the only species left in the Yangtze river. Unfortunately, the porpoise is facing extinction. What is it? The Yangtze finless porpoise is a dolphin species living in the Yangtze River in southern China. It is one of the very few dolphin species that live in freshwater, and the only one that survived in the Yangtze river after the Baiji Dolphin was declared functionally extinct in 2006. It characteristically is about 2 meters long, has no fins -as the name suggests- and no beak. Its mouth however is curved upwards like a smile, giving the Porpoise and cute and friendly face. It feeds on small fish, crustaceans and molluscs. Sadly, the Yangtze finless Porpoise is considered "critically endangered" as there are only about 1000 of them left. Why i...

Linking climate change and inequality - 'The Great Carbon Divide'

Hey everyone, Have you heard of 'The great carbon divide‘? It is often referred to as the 'carbon footprint gap' or the 'emissions imbalance‘, and produces frightening numbers. The great carbon divide describes the huge gap between the amount of carbon dioxide the rich versus the poor emit, and these numbers shocked even us. What does this mean? There have been many different studies, and all of them show terrifying results. One study from the Guardian and Oxfam, reports that the richest 1% of the world's population emit more carbon than the poorest 66%. The richest 1% consist of 77 million people, which may seem like a lot at first, but the poorest 66% refers to over 5 billion people! Africa, which is home to 17% of the world's population, only causes 4% of the world's emissions. This top 1% emitted 16% of global CO2 emissions in 2019, that's 5.9 billion tonnes of CO2. Modelling suggests that it would take someone who isn't in the top 1% about 150...

Why Didn't People Act Sooner On The Climate Crisis?

Hi Everyone! Welcome back to Green World, where today I wanted to talk about why people didn't act sooner about the climate crisis , when we have known about this issue for decades. I asked myself this too, and it wasn't until I read the chapter about it in Greta Thunberg's book that I started to understand the reasons behind why action was not taken sooner, and why this crisis has been allowed to escalate as far as it has. As someone who has only been on the planet for 14 years, a part of me does resent people around long before I was for not having acted on an issue that they knew would continue to affect people around the world. They knew it was not an issue that would go away, so why didn't they act, when it was easier to do so? Changing our now very ingrained habits is so difficult, whereas fifty years ago, ways of life could have been more easily influenced. Well, there are a few reasons why action was not taken to combat cl...

Amazon Rainforest series - part 2: eco system and food chains

Welcome back to our Amazon mini-series! Today, we're going to talk about the eco system and food chains of the Amazon Rainforest. The eco system is very complex. If you read our last Amazon post you will know the great number of species that call the Amazon Rainforest home. The Amazon Rainforest is a very accurate name for it. Massive amounts of rain fall on the forest every year. Most of that rain is blown in from the Atlantic Ocean. The rest comes from evaporation. The rainforest is known to be full of life. It provides one of the last refuges for jaguars , harpy eagles and pink river dolphins . But the rainforest is home to many more animals than that. Everyone has heard of poison dart frogs right? In fact, the Amazon Rainforest contains 1 in 10 of all known animal species on Earth! That's a lot of animals! The Amazon is home to over 1 000 species of birds, from hummingbirds to eagles. Macaws are probably the most well...

Green World

Search This Blog