How jellyfish in Gothenburg’s archipelago reveal impact of climate change

A global increase in jellyfish sparked by climate change is impacting communities in the Gothenburg archipelago, with local restaurants and fishing reporting the effects.

How jellyfish in Gothenburg's archipelago reveal impact of climate change
Marine biologist Björn Källström holds a jellyfish he has collected at Vrångö. Photo: Peter Seenan

Jellyfish numbers are rising globally because of climate change and human impact on the marine environment, with the worrying trend set to continue.

Researchers report an increase in comb jellies in Swedish waters along with the 2018 arrival of an “alien species” called the clinging jellyfish, which delivers a painful sting.

But they warn there is not enough research to understand the full extent of their impact and further consequences at a local level.

To uncover the extent of the increased amount of jellyfish in the local environment, the writers of this article headed to Vrångö island with Björn Källström, a marine biologist at the University of Gothenburg. We didn’t have to search for long: jellyfish are visible both in the water and on land.

Marine biologist Björn Källström reports that human activity is responsible for the rise in jellyfish. Photo: Peter Seenan

When our team captured an American comb jellyfish, Källström commented: “This is an invasive alien species, which arrived in Swedish waters in 2006. In summer, people in Sweden report thousands of them.”

Aside from reducing the amount of fish in the sea, jellyfish clog nets.

“When fishing mackerel, we can’t catch anything,” Andreas Olsson Wijk, a local fisherman, said. “[The jellyfish] fill the net and it’s impossible to get anything into the boat.”

Fisherman and restaurateur Andreas Olsson Wijk says jellyfish prevent the catching of mackerel. Photo: Peter Seenan

According to Håkan Karlsten, a local hotel owner who has lived on the island permanently since 1991, “small fishing boats have problems because they are not strong enough to take anything. They don’t have tools to take them out, or strong motors to counteract the weight of the jellyfish in the nets.”

Professor Lena Granhag, lecturer of Maritime Studies at Chalmers University, explained that the warming of sea waters, caused by climate change, leads to the presence of the American comb jellyfish in Sweden and the Baltic Sea.

Excessive levels of nutrients in the water, called eutrophication, also contribute to the growth of the jellyfish population. The main nutrients involved in this process are nitrogen and phosphorus, which can be found in farming pesticides and fertilisers.

“More nutrients will lead to more blooms,” she said. “When there are lots of nutrients, algae will bloom. Jellyfish can eat the algae directly, but they actually capture zooplankton – or small shrimp – that in turn have algae on them.”

Källström explained how direct human action is also relevant. Ships can be responsible for introducing other invasive species, like the clinging jellyfish, which “came in 2018 with a big cargo ship to Swedish waters and managed to survive”.

Overfishing is also “a factor leading to more jellyfish”, he added, since fish are one of their main predators.

A jellyfish, or ‘manet’ as they are called in Swedish. Photo: Peter Seenan

Increasing jellyfish are a global trend. Along the coast of Haifa in Israel, jellyfish cause a lot of damage every year, with this increasing in the last few years. The Society of Ecology and Environmental Sciences in Israel points to climate change as a cause, with overfishing and the farming sector part of the reason behind the altered ecosystem.

Jellyfish blooms can also pose practical challenges, such as clogging the cooling water streams of nuclear power plants. Reactors at Sweden’s Oskarshamn nuclear power plant were clogged in 2005 and 2013. It happens regularly at Japan’s nuclear power plants during the summer in a tsunami-stressed energy sector. Nuclear power plants in Scotland face a similar challenge. 

“The problem in Sweden and in many other places is that we don’t have any long-term series of measurements of monitoring jellyfish. It’s actually quite difficult to say for any place in Sweden or many places in the world that jellyfish are in fact increasing. However, there are several signs of increase,” Källström said.

Jellyfish at Vrångö where locals say they are causing problems for fishing. Photo: Peter Seenan

A deeper understanding for the increase of jellyfish and their link with climate change depends on greater economic investment in the collection of data and marine research.

Initiatives on crowd-sourced data, such as the reports by the Swedish Agency for Marine and Water Management, are one solution to the lack of research about jellyfish numbers and its relation to climate change. “This is citizen science, people are helping scientists,” Källström said. 

Global trends suggest the impact of jellyfish goes beyond stung tourists and clogged nuclear power plants, to affecting local economies, marine ecosystems and local food production – an unsettling indicator of human action and its consequences for our climate that local actors and the international community fail to address.

Article by Gothenburg University students Sandra Daniel, Mireia Jimenez Barcelo, Javad Maleki, Peter Seenan and Marina Panicheva

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Electric trucks pick up speed at Volvo’s Sweden factory

At Volvo's factory near Gothenburg, the global truck industry is undergoing a revolution.

Electric trucks pick up speed at Volvo's Sweden factory

Using a motorised arm, a worker at Volvo’s factory near Gothenburg slowly guides massive black blocks alongside a chassis, the three tonnes of batteries soon to power an electric truck.

“This is where the difference lies,” explains Sandra Finer, vice president of operations at the Swedish site.

On the assembly line, “we use the same people, the same equipment and the same process, (but)… when we build the electric truck we dock the electric module instead of an engine for the diesel trucks.”

Electric heavy trucks are now mass produced in Europe, North America and China and have been rolled out faster than expected — though it will still be a while before they overtake polluting diesel trucks in number.

“It is a really exciting moment we’re living in regarding electric trucks,” Felipe Rodriguez, an independent expert at analysis group International  Council on Clean Transportation (ICCT), told AFP. “Just four or five years ago, people would have said ‘You’re crazy, that’s not going to happen. Diesel is king, it can’t be beaten’.”

Electric heavy trucks require massive amounts of energy to propel their heavy loads, raising questions about their range and recharging capabilities. They need charging terminals dozens of times more powerful than those made for electric cars.

The electric trucks are also more expensive, currently costing between two to three times more than a traditional diesel model, according to industry experts.

However, those prices are expected to go down and the higher up-front price can be offset by cheaper running costs using electricity, as well as different  country-specific incentives.

Race to launch

Spurred by increasingly strict EU regulations aimed at reducing CO2 emissions as well as massive Chinese state support for its national manufacturers, the sector is determined to press ahead.

There has been “a reckoning in the industry that they will not be able to hold on to their diesel engines forever,” Rodriguez said. “There is now a race to really develop and launch these electric trucks on the market.”

In 2022, electric trucks accounted for a tiny portion of heavy trucks on the world’s main markets — just one or two percent, with 40,000 to 50,000 units sold worldwide, most of them in China, according to data from trade experts.

But the main Western truck makers — Germany’s Daimler and Man, Sweden’s Volvo and its French subsidiary Renault Trucks, and the other Swedish manufacturer Scania — have invested heavily.

US manufacturer Tesla, which has been hugely successful with its electric cars, also aims to break into the e-trucks sector, with its “Semi” model promising a range of up to 800 kilometres (500 miles).

The global truck market is sizable, estimated at more than $200 billion per year with almost six million units sold.

“In 2030, 50 percent of the volume that we sell for Volvo Trucks should be zero emissions … and in 2040, everything that we sell should be zero emissions,” Roger Alm, head of Volvo Group’s trucks division, told AFP.

That more or less corresponds to the level necessary to achieve the objectives of the Paris Agreement to decarbonise road transport, according to the ICCT.

Diesel long-haul trucks emit around one kilo of CO2 per kilometre, the ICTT estimates.

With Europe’s current electricity mix, which still comprises a significant amount of coal and gas, the carbon footprint of an electric truck is two-thirds lower than that of a diesel truck.

Spreading around the world

Electric trucks are expected to account for 90 percent of the truck market by 2040, according to ICCT.

“It has started to really take off and grow in the Northern parts of Europe and in North America,” Alm said. “Now it’s moving into the southern parts of Europe and we also have new markets in Africa, for example, Australia, Brazil, so it’s expanding country by country.”

Together with other manufacturers, Volvo, the world’s second-biggest truck builder, has agreed to take part in a vast European project to increase the number of truck charging stations, currently one of the weak points holding back their adoption.

To recharge an electric truck quickly, a charging station must be up to 10 times more powerful than a charging station for an electric car.