Arctic Ocean

Frequent marine heat waves in the Arctic Ocean will be the norm, says new study

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Frequent marine heatwaves in the Arctic Ocean will be the norm
The figure shows the most powerful heat wave in the Arctic Ocean to date in 2020, which continued for 103 days. The cumulative heat intensity sums up the daily anomalies in water temperature recorded over the duration of the heat wave in degrees Celsius.

Marine heat waves will become a regular occurrence in the Arctic in the near future and are a product of higher anthropogenic greenhouse-gas emissions, according to a study just released by Dr. Armineh Barkhordarian from Universität Hamburg’s Cluster of Excellence for climate research CLICCS.

Since 2007, conditions in the Arctic have shifted, as confirmed by data recently published in the journal Communications Earth & Environment. Between 2007 and 2021, the marginal zones of the Arctic Ocean experienced 11 marine heat waves, producing an average temperature rise of 2.2 degrees Celsius above seasonal norm and lasting an average of 37 days. Since 2015, there have been Arctic marine heat waves every year.

The most powerful heat wave to date in the Arctic Ocean was in 2020; it continued for 103 days, with peak temperatures that were four degrees Celsius over the long-term average. The probability of such a heat wave occurring without the influence of anthropogenic greenhouse gases is less than 1%, as calculated by Barkhordarian’s team at the Cluster of Excellence CLICCS. By doing so, they have narrowed down the number of plausible climate scenarios in the Arctic. According to the study, annual marine heat waves will be the norm.

The Arctic entered a new phase

In the study, Barkhordarian also proves for the first time that heat waves are produced when sea ice melts early and rapidly after the winter. When this happens, considerable heat energy can accumulate in the water by the time maximum solar radiation is reached in July.

“In 2007, a new phase began in the Arctic,” says Barkhordarian, an expert on climate statistics. “There is less and less of the thicker, several-year-old ice, while the percentage of thin, seasonal ice is consistently increasing.” However, the thin ice is less durable and melts more quickly, allowing incoming solar radiation to warm the water’s surface.

Officially, it is considered to be a marine heat wave when temperatures at the water’s surface are higher than 95% of the values from the past 30 years for at least five consecutive days.

“Not just the constant loss of sea ice but also warmer waters can have dramatic negative effects on the Arctic ecosystem,” says Barkhordarian. Food chains could collapse, fish stocks could be reduced, and overall biodiversity could decline.

Global Warming Puts the Arctic on Thin Ice.

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Answers to questions about the Arctic’s shrinking ice cap and its global significance.

1.    Why are global warming specialists watching the Arctic so closely?

2.    What kinds of changes are taking place in the Arctic now?

3.    How does this dramatic ice melt affect the Arctic?

4.    Will Arctic ice melt have any effects beyond the polar region?

5.    Can we do anything to stop global warming?

 

1. Why are global warming specialists watching the Arctic so closely?

The Arctic is global warming’s canary in the coal mine. It’s a highly sensitive region, and it’s being profoundly affected by the changing climate. Most scientists view what’s happening now in the Arctic as a harbinger of things to come.

Since 1979, the size of the summer polar ice cap has shrunk more than 20 percent.

2. What kinds of changes are taking place in the Arctic now?

Average temperatures in the Arctic region are rising twice as fast as they are elsewhere in the world. Arctic ice is getting thinner, melting and rupturing. For example, the largest single block of ice in the Arctic, the Ward Hunt Ice Shelf, had been around for 3,000 years before it started cracking in 2000. Within two years it had split all the way through and is now breaking into pieces.

The polar ice cap as a whole is shrinking. Images from NASA satellites show that the area of permanent ice cover is contracting at a rate of 9 percent each decade. If this trend continues, summers in the Arctic could become ice-free by the end of the century.

3. How does this dramatic ice melt affect the Arctic?

The melting of once-permanent ice is already affecting native people, wildlife and plants. When the Ward Hunt Ice Shelf splintered, the rare freshwater lake it enclosed, along with its unique ecosystem, drained into the ocean. Polar bears, whales, walrus and seals are changing their feeding and migration patterns, making it harder for native people to hunt them. And along Arctic coastlines, entire villages will be uprooted because they’re in danger of being swamped. The native people of the Arctic view global warming as a threat to their cultural identity and their very survival.

4. Will Arctic ice melt have any effects beyond the polar region?

Yes — the contraction of the Arctic ice cap is accelerating global warming. Snow and ice usually form a protective, cooling layer over the Arctic. When that covering melts, the earth absorbs more sunlight and gets hotter. And the latest scientific data confirm the far-reaching effects of climbing global temperatures.

Rising temperatures are already affecting Alaska, where the spruce bark beetle is breeding faster in the warmer weather. These pests now sneak in an extra generation each year. From 1993 to 2003, they chewed up 3.4 million acres of Alaskan forest.

Melting glaciers and land-based ice sheets also contribute to rising sea levels, threatening low-lying areas around the globe with beach erosion, coastal flooding, and contamination of freshwater supplies. (Sea level is not affected when floating sea ice melts.) At particular risk are island nations like the Maldives; over half of that nation’s populated islands lie less than 6 feet above sea level. Even major cities like Shanghai and Lagos would face similar problems, as they also lie just six feet above present water levels.

Rising seas would severely impact the United States as well. Scientists project as much as a 3-foot sea-level rise by 2100. According to a 2001 U.S. Environmental Protection Agency study, this increase would inundate some 22,400 square miles of land along the Atlantic and Gulf coasts of the United States, primarily in Louisiana, Texas, Florida and North Carolina.

A warmer Arctic will also affect weather patterns and thus food production around the world. Wheat farming in Kansas, for example, would be profoundly affected by the loss of ice cover in the Arctic. According to a NASA Goddard Institute of Space Studies computer model, Kansas would be 4 degrees warmer in the winter without Arctic ice, which normally creates cold air masses that frequently slide southward into the United States. Warmer winters are bad news for wheat farmers, who need freezing temperatures to grow winter wheat. And in summer, warmer days would rob Kansas soil of 10 percent of its moisture, drying out valuable cropland.

5. Can we do anything to stop global warming?

Polar Action Guide

Yes. When we burn fossil fuels — oil, coal and gas — to generate electricity and power our vehicles, we produce the heat-trapping gases that cause global warming. The more we burn, the faster churns the engine of global climate change. Thus the most important thing we can do is save energy.

And we can do it. Technologies exist today to make cars that run cleaner and burn less gas, generate electricity from wind and sun, modernize power plants, and build refrigerators, air conditioners and whole buildings that use less power. As individuals, each of us can take steps to save energy and fight global warming.

Source: NGC

 

 

Melting Arctic Ice Will Make Way for More Ships–and More Species Invasions.

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A new study shows immense increases in shipping are likely over the North Pole and Arctic Ocean in the coming years, alerting scientists who study invasive species

The rare ships that have ventured through the harsh, icebound Arctic Ocean require reinforced hulls and ice-breaking bows that allow them to plow through dense ice as much as two meters deep, and face hazardous conditions in remote locations for long periods of time. Arctic sea ice now is melting so rapidly each summer due to global warming, however, that ships without ice-breaking hulls will be able to cross previously inaccessible parts of the Arctic Ocean by 2050. And light-weight ships equipped to cut through one meter of ice will be able to travel over the North Pole regularly in late summer, according to a new study published March 4 in Proceedings of the National Academy of Sciences Plus.

That’s good news for economic development because it offers many new and faster routes from east to west, shaving 40 percent off transportation time and fuel costs compared with shipments via the Suez Canal. But the geographic extent of trade routes across the Arctic is worrisome for scientists who study invasive species.

Ships traveling regularly in the Northwest Passage, beyond the Northern Sea Route and through the central Arctic Ocean, will likely bring new invaders to the Arctic as well as to northern ports. Mosquitoes and forest beetles are expected to survive hidden in cargo, for example. Hearty marine organisms, such as mussels and barnacles, will likely tag along as larvae in ballast tanks or in niche areas on vessel hulls. When new species flourish in a new environment they can become harmful, damaging local ecosystems and threatening native plants and animals, much as the Japanese vine known as kudzu has overrun the southern U.S. Economic costs associated with new pests have been significant—for example, the influx of zebra mussels into the Great Lakes has been estimated at $1 billion annually.

“The temptation for many new ships to enter [the Arctic] will be huge,” says University of California, Los Angeles, geographer Laurence Smith, lead author of the new study. Arctic shipping already has grown by leaps and bounds in just the past few years. In 2012, which set a record for lowest sea ice extent, a total of 46 ships—the most ever—traversed the Arctic Ocean. Thirty-four ships made the passage in 2011 whereas just four had done so the year before. For context, 19,000 ships pass through the Suez Canal annually.

Sea ice has long been a barrier to shipping across the Arctic Ocean as well as to species. Already, shipping is by far the most common pathway for marine invasive species, responsible for 69 percent of species introductions to marine areas, followed by aquaculture at 41 percent (non-native species can have more than one pathway of introduction, meaning some double counting.) The most common transport method is ships’ ballast water. Organisms can also hitch a ride in nooks and crannies on a ship’s hull, known as hull fouling. And organisms such as forest pests and mosquitoes can survive long trips in pallets and in cargo such as tires.

“Invasive species are one of those things that once the genie is out of the bottle, it’s hard to put her back in,” says climate scientist Jessica Hellmann of the University of Notre Dame who was not involved with this study. Hellmann studies the impact of climate change on invasive species and ecological systems. As Arctic ice melts, new ports will be connected and shorter passages between existing ports will lead to new opportunities for invasive species to spread, she says.

Cold storage
Mario Tamburri, a marine scientist and director of the Maritime Environment Resource Center at the University of Maryland Center for Environmental Science, has been researching survivorship and reproduction of organisms likely to be transported by ships by mimicking the conditions of shipping traffic. New colder, shorter routes afforded by the retreat of ice help invaders, such as mussels, barnacles and crabs, on a biological level, Tamburri says. Cold water slows metabolism of organisms, which can sustain themselves in low food conditions. “It’s like putting your groceries on ice,” he says.

Shorter routes also mean more organisms either attached to the hull or in ballast water are now more likely to survive the journey. Previously, the high heat and lack of light of longer trips outside the Arctic killed them off. “When ships now transport goods through the Panama Canal, for instance, through warm water and freshwater, natural barriers to invasive species are built into the shipping routes,” Tamburri says. “In the Arctic, those barriers go away.”

Ballast water and bivalves
Murmansk, Russia, a leading global port and the largest city north of the Arctic Circle, is one area that ice-free routes will likely open up further this summer. As more ships exchange ballast water for cargo, native species in places like Murmansk can quickly lose out against new species that have no checks and balances, such as marine species like bivalves that can be dispersed by larvae in ballast water as well as cold-water adapted adults, including green crabs.

Lewis Ziska, a plant physiologist with the U.S. Department of Agriculture’s Agricultural Research Service, says that once introduced, a new species can outcompete everything that has evolved over millennia. Although some nonnative species are innocuous, others thrive because there have no predators. Nothing controls them in the natural system, and they are better at filtering food out of the water than their native cousins. “Invasives use up the lion’s share of resources, and whatever biodiversity that was there falls apart,” Ziska says.

When new interlopers take hold, one or two tend to become very well suited for that environment and dominate it. The natural biodiversity diminishes, Ziska says. Scientists are beginning to catalogue and classify native and nonnative species at ports near oil facilities in Alaska. No large obvious invasions by marine traffic have occurred yet in the high latitude environment but Ziska and others scientists say no one can be sure. Scientists are only now beginning to look closely.

“We weren’t expecting the Arctic to change this quickly,” Ziska notes, adding that the implications for not only human traffic but also for biology are worrisome. “It’s basically opening up the entire Arctic region as a huge playground for invasive species. New things, new biological organisms are going into the area where they have never been seen before. The consequences of that are, quite frankly, are completely unknown.”

Source: Scientific American.

Arctic ice melt ‘like adding 20 years of CO2 emissions’.

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The loss of Arctic ice is massively compounding the effects of greenhouse gas emissions, ice scientist Professor Peter Wadhams has told BBC Newsnight.

White ice reflects more sunlight than open water, acting like a parasol.

Melting of white Arctic ice, currently at its lowest level in recent history, is causing more absorption.

Prof Wadhams calculates this absorption of the sun’s rays is having an effect “the equivalent of about 20 years of additional CO2 being added by man”.

The Cambridge University expert says that the Arctic ice cap is “heading for oblivion”.

In 1980, the Arctic ice in summer made up some 2% of the Earth’s surface. But since then the ice has roughly halved in area.

“Thirty years ago there was typically about eight million square kilometres of ice left in the Arctic in the summer, and by 2007 that had halved, it had gone down to about four million, and this year it has gone down below that,” Prof Wadhams said.

And the volume of ice has dropped, with the ice getting thinner:

“The volume of ice in the summer is only a quarter of what it was 30 years ago and that’s really the prelude to this final collapse,” Prof Wadhams said.

Parts of the Arctic Ocean are now as warm in summer as the North Sea is in winter, Prof Wadhams said.

Radiation absorbed

The polar ice cap acts as a giant parasol, reflecting sunlight back into the atmosphere in what is known as the albedo effect.

But white ice and snow reflect far more of the sun’s energy than the open water that is replacing it as the ice melts.

Instead of being reflected away from the Earth, this energy is absorbed, and contributes to warming:

“Over that 1% of the Earth’s surface you are replacing a bright surface which reflects nearly all of the radiation falling on it with a dark surface which absorbs nearly all.

“The difference, the extra radiation that’s absorbed is, from our calculations, the equivalent of about 20 years of additional CO2 being added by man,” Prof Wadhams said.

If his calculations are correct then that means that over recent decades the melting of the Arctic ice cap has put as much heat into the system as all the CO2 we have generated in that time.

And if the ice continues to decline at the current rate it could play an even bigger role than greenhouse gases.

UK weather effect

Professor Wadhams stresses that there are uncertainties – cloud cover over the Arctic could change and help reflect back some of the sun’s radiation.

But then another greenhouse gas – methane, currently trapped in the Arctic permafrost – could be released with warming and make matters worse.

The melting ice could have knock-on effects in the UK. Adam Scaife, from the Met Office Hadley Centre told Newsnight it could help explain this year’s miserable wet summer, by altering the course of the jet stream.

“Some studies suggest that there is increased risk of wet, low pressure summers over the UK as the ice melts.”

There may be an effect for our winters too: “Winter weather could become more easterly cold and snowy as the ice declines,” Mr Scaife said.

Opinions vary on the date of the demise of summer sea ice. The Met Office says it is not expecting the Arctic to be completely ice-free in summer until after 2030.

Source: BBC.