Earth Wise

A look at our changing environment.

You are here: Home / Archives for antarctica

antarctica

Trouble For Emperor Penguins | Earth Wise

By Leave a Comment

Emperor penguins are the tallest and heaviest of all living penguin species.  The loss of sea ice in Antarctica last year has led to unprecedented breeding failure in some emperor penguin colonies.

In a study published by the British Antarctic Survey, researchers found that no chicks survived from four of the five known emperor penguin colonies in the central and eastern Bellinhausen Sea.   Satellite images showed the loss of sea ice at breeding sites, well before chicks would have developed waterproof feathers.

Emperor penguins are dependent on stable sea ice that is firmly attached to the shore from April through the end of the year.  Arctic sea ice reached an all-time low in December 2022 with the most extreme loss seen in the central and eastern Bellinghausen Sea where there was a 100% loss of sea ice late the year.

This year, the sea ice extent in Antarctica is still far below all previous records for this time of year.  As of August, when oceans normally are freezing up, there were still areas that were ice-free.

Emperor penguin populations have not had to contend with large-scale hunting, habitat loss, overfishing, or other human-caused problems in the modern era, but climate change may be their undoing.  They have previously responded to incidents of sea ice loss by moving to more stable sites in the following year.  But this strategy will not be successful if the sea ice habitat is affected across entire regions of Antarctica.

Scientists are predicting that 90% of emperor penguin colonies will be quasi-extinct by the end of the century, assuming current global warming trends continue.

**********

Web Links

Loss of sea ice causes catastrophic breeding failure for emperor penguins

Photo, posted October 7, 2017, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Polar Ice Melting | Earth Wise

By Leave a Comment

Sea levels are rising and ocean warming is responsible for the bulk of that rise.  As water heats up, it expands, which drives up sea levels.  But on top of that, global warming is melting the polar ice sheets, and that is leading to about a quarter of the world’s sea level rise. So far, polar melting has fueled about an inch of sea level rise, two-thirds from Greenland and one third from Antarctica.   According to scientists, by the end of this century, melting polar ice caps could raise sea levels between 6 and 10 inches.

The seven worst years for polar ice sheet melting have occurred during the past decade.  The worst year on record was 2019.  The loss in 2019 was driven by an Arctic summer heatwave, which resulted in record melting from Greenland, amounting to nearly 500 billion tons melted that year.  Antarctica lost 180 billion tons of ice that year, mostly due to melting glaciers and record melting from the Antarctic Peninsula.

Ice losses from Greenland and Antarctica can now be reliably measured by satellites in space.  A team of researchers led by Northumbria University in the UK has combined 50 satellite surveys taken between 1992 and 2020.

They have found that the Earth’s polar ice sheets have lost over 8,000 billion tons of ice over that time period.  That much ice corresponds to an ice cube roughly 12 miles high.

The satellite technology is now at the stage where the ice sheet status can be continuously updated.  Such monitoring is critical to predict the future behavior of the ice sheets and provide risk warnings of the dangers that coastal communities around the world will face.

**********

Web Links

Polar ice sheet melting records have toppled during the past decade

Photo, posted December 19, 2017, courtesy of Jasmine Nears via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Low Antarctic Sea Ice | Earth Wise

By Leave a Comment

Recent satellite observations of the sea ice in the Antarctic found the lowest level of ice cover ever seen in the forty years that these observations have been made.  As of February 8th, there were only 849,000 square miles of the Southern Ocean covered with ice.  The previous record low was measured last February 24th when the total coverage was 876,000 square miles.  Ice melting was likely to continue as the month went on.

This past January had already set a new record for that month’s mean extent of ice coverage at 1.24 million square miles. This rapid decline in sea ice has been going on for the past six years and is very unusual.  Average Antarctic ice cover hardly changed at all during the previous thirty-five years.

Antarctic sea ice generally reaches its maximum extent in September or October and its minimum extent in February.  At its maximum, the sea ice cover in the Antarctic is generally between 6.9 and 7.7 million square miles.   On the other hand, there are some places where the sea ice melts completely during the Southern Hemisphere summer.  Sea ice varies much more in the Antarctic than in the Arctic where the ice is much thicker.

Climate warming at the poles is much higher than at lower latitudes.  Nonetheless, it is not yet clear whether what we are seeing is the beginning of the end of summer sea ice in the Antarctic, or whether this is just a new phase characterized by low but still stable sea ice cover in the summer.

**********

Web Links

Record low sea ice cover in the Antarctic

Photo, posted January 24, 2012, courtesy of Rob Oo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Disappearing Glaciers | Earth Wise

By Leave a Comment

Glaciers are massive bodies of slowly moving ice.  Glaciers form on land, and represent the snows of centuries compressed over time.  They move slowly downward under the influence of their own weight and gravity. 

Most of the glaciers on the planet are found in the polar regions, including Antarctica, the Canadian Arctic, and Greenland.  Glaciers can also be found closer to the equator in mountain ranges, such as the Andes Mountain range in South America.  Glaciers are always changing, accumulating snow in the winter and losing ice to melting in the summer.  But in recent times, the melting has been outpacing the accumulation.

A new international study led by researchers at Carnegie Mellon University’s College of Engineering has produced new projections of glacier loss through the century under different emissions scenarios.  According to the projections, the world could lose as much as 41% of its total glacier mass this century – or as little as 26% – depending on climate change mitigation efforts. 

In a future with continued investments in fossil fuels (sometimes referred to as the “business as usual” scenario), more than 40% of the glacial mass will be gone by 2100, and more than 80% of glaciers by number could disappear.  Even in a best case scenario where the increase in global mean temperature is limited to 1.5° degrees Celsius relative to pre-industrial levels, more than 25% of glacial mass will be gone, and nearly 50% of glaciers by number will disappear.

Glaciers take a long time to respond to changes in climate.  A complete halt to emissions today would take anywhere from 30 to 100 years to be reflected in glacier mass loss rates.

**********

Web Links

Team projects two out of three glaciers could be lost by 2100

Ice, Snow, and Glaciers and the Water Cycle

Photo, posted August 13, 2010, courtesy of Kimberly Vardeman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Growing Threat To Wheat | Earth Wise

By Leave a Comment

Wheat is one of the most widely-grown crops in the world and plays a major role in human nutrition.  In fact, wheat contributes approximately 20% of the protein and 20% of the calories consumed by humans globally.  It is grown on every continent except Antarctica.  

But wheat is under growing attacks from harmful toxins.  According to a new study by researchers from the University of Bath and the University of Exeter in the U.K., almost half of wheat crops across Europe are impacted by the fungal infection that gives rise to mycotoxins.

Mycotoxins are naturally occurring toxins produced by the fungus that causes Fusarium Head Blight.  Fusarium Head Blight is a disease that affects wheat and other grains growing in the field. Eating products contaminated with mycotoxins can cause sickness in humans and livestock, including vomiting and other gastrointestinal problems.

In the study, the research team examined 10 years of government and agribusiness data, which tracked Fusarium mycotoxins in wheat entering the food and animal supply chains across Europe and the U.K.  Half of the wheat intended for human food in Europe contained the Fusarium mycotoxin.  In the UK, 70% of wheat was contaminated.

Governments set legal limits on mycotoxin contamination levels in wheat that is to be consumed by humans. But with the ubiquitous nature of these mycotoxins, the effect of constant, low-level exposure in the diet over the course of a lifetime is not known. 

With climate change and the war in Ukraine already impacting both wheat yield and price, preventing toxin contamination is critical to help maintain a stable crop price and to protect global good security. 

**********

Web Links

Harmful fungal toxins in wheat: a growing threat across Europe

Photo, posted July 11, 2011, courtesy of Maria Keays via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Return Of The Fin Whale | Earth Wise

By Leave a Comment

The fin whale is the second largest whale species and therefore the second largest creature on Earth.  They can grow to more than 80 feet in length.  From 1904 to 1976, there was massive industrial whaling in the Southern Ocean surrounding Antarctica.  During that period, whalers killed about 700,000 fin whales, reducing their population by 99%.  The species was nearly extinct.

In 1982, the International Whaling Commission voted to ban commercial whaling.  Since that time, fin whales started to make a comeback in their historical feeding grounds.

During a nine-week expedition in the waters around the Antarctic Peninsula, researchers encountered the largest gathering of fin whales ever documented.  About 150 fin whales were seen diving and lunging against the water’s surface.  It was a feeding frenzy triggered by large amounts of krill in the water.  The actions of the whales are known as a “whale pump” that drives the krill to the surface.  Not only does it provide huge amounts of food for the whales but also for other animals, including seabirds and seals.

Forty years after the commercial whaling ban, the number of fin whales has been increasing.  Large groups were observed in a 2013 survey.  Aerial surveys in 2018 and 2019 recorded 100 groups of fin whales, usually composed of a just a handful of individuals.  They did document eight large groups of up to 150 individuals.

Not all species of whales have rebounded so successfully since the whaling ban.  The rebound in fin whale population is not only good for the whales, but for the entire ecosystem in the Southern Ocean.  It is a glimmer of good news in a time of great challenges for global biodiversity and for marine life in particular.

**********

Web Links

Once Facing Extinction, Massive Fin Whales Have Returned to Antarctic Waters

Photo, posted November 15, 2007, courtesy of Gregory Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

January Climate Report Card | Earth Wise

By Leave a Comment

January was the sixth-warmest January in the 143 years of global climate record keeping.  The global land and ocean surface temperature was 1.6 degrees Fahrenheit above the 20th century average.

Meanwhile, the United States had its coolest January since 2014, although the month still ranked nearly a degree above the long-term average across the nation.  This January was also the driest January in eight years and was one of the top- 15 driest Januarys on record.  That being said, there was the so-called Bomb Cyclone late in the month that dumped 1-2 feet of snow and brought blizzard conditions along the eastern seaboard and set a one-day snowfall record in Boston.

Global conditions and regional and local conditions can be very different.  In the big picture, January was the 46th consecutive January and the 445th consecutive month with temperatures above the 20th century average.

And while the US had a fairly cool January, South America saw its second-warmest January on record, Asia had its fourth warmest, and Oceania had its seventh warmest.

Apart from temperatures, Antarctic sea ice coverage was the second smallest January extent in 44 years.  Arctic ice was 208,000 square miles below the 1981-2010 average, although it was the largest since 2009.

Even as the global climate warms, local and regional climate conditions will continue to have unique and variable characteristics over the course of time.  Every time there’s a bout of cold weather, it isn’t time to stop being concerned about climate change.

**********

January 2022 was Earth’s 6th warmest on record

Photo, posted January 6, 2013, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Antarctic Ice Collapse | Earth Wise

By Leave a Comment

In Antarctica, a huge chunk of the Larsen B Ice Shelf collapsed suddenly and spectacularly in January.

The Larsen Ice Shelf is located on the northeastern side of the Antarctic Peninsula on the Weddell Sea.  It was formed over the course of more than 12,000 years.  The Weddell Sea used to be a completely frozen body of water.  The famous Ernest Shackleton expedition in 1915 was trapped in its ice.  But the Antarctic Peninsula has been steadily warming in recent decades.

The Larsen A Ice shelf collapsed in 1995 and the 1,250-square-mile Larsen B Ice Shelf collapsed in 2002.  After that event, a portion of the detached ice shelf refroze in 2011 and was attached to the Scar Inlet Ice Shelf.  The refrozen ice was called the Larsen B embayment.

In January, the embayment broke apart, taking with it a portion of the Scar Inlet Ice Shelf.  It disintegrated within a matter of days.  The combined Larsen Ice Shelves – called A, B, C, and D – once extended along a 1000-mile stretch of the eastern Antarctic Peninsula.  Since 1995, it has shrunk from 33,000 square miles to 26,000 square miles.

These ice shelves float on the ocean, so their loss does not actually increase global sea levels.   However, the shelves act as dams that hold back glaciers located on the land behind them.  The loss of Antarctic ice shelves dramatically increases the rate at which glaciers flow into the sea, and that does increase global sea levels. 

Now that the sea ice from the Larsen B embayment is gone, it is likely that there will be additional inland ice losses from the newly exposed glaciers.

**********

Remnant of Antarctica’s Larsen B Ice Shelf Disintegrates

Photo, posted February 13, 2018, courtesy of NASA/Nathan Kurtz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Invasive Species On Ships In Antarctica | Earth Wise

By Leave a Comment

The Southern Ocean around Antarctica is the most isolated marine environment on Earth.  Antarctica’s native species have been isolated for the last 15-30 million years.  As a result, wildlife there has not evolved the ability to tolerate the presence of many groups of species.

New research by the University of Cambridge and the British Antarctic Survey has traced the global movements of all the ships entering Antarctic water and has found that Antarctica is connected to all regions of the globe via ship activity to an extent much greater than previously thought.  Fishing, tourism, research, and supply ships are exposing Antarctica to invasive, non-native species that threaten the existing ecosystems.

In all, the research identified over 1,500 ports with links to Antarctica.  From all these places, non-native species including mussels, barnacles, crabs, and algae attach themselves to ships’ hulls.  The process is known as biofouling. 

The greatest concern is the movement of species from pole to pole.  These species are already cold-adapted.  They may come on tourist or research vessels that spend the northern hemisphere summer in the Arctic before traveling south for the Antarctic summer season.

Mussels have no competitors in Antarctica should they be accidentally introduced.  Shallow water crabs would introduce a new form of predation that Antarctic animals have never encountered before.

Current biosecurity measures to protect Antarctica, such as cleaning ships’ hulls, focus on a small group of so-called gateway ports.  The new findings indicate that these measures need to be expanded to protect Antarctic waters from non-native species.

**********

Invasive species ‘hitchhiking’ on ships threaten Antarctica’s unique ecosystems

Photo, posted April 12, 2016, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Melting Himalayan Glaciers | Earth Wise

By Leave a Comment

The great mountain ranges of central Asia, including the Himalayas, contain the third-largest deposit of ice and snow in the world, trailing only Antarctica and the Arctic.  The Himalayan range contains about 15,000 glaciers, and is part of a region widely referred to as the Third Pole due to its extraordinary reserves of freshwater.

But in recent years, scientists have observed an increase in the rate of Himalayan glacier loss.  According to a new study led by researchers from the University of Leeds in the UK, the accelerating melting of the Himalayan glaciers threatens the water supply of millions of people in Asia. 

In the study, researchers reconstructed the reach of the Himalayan glaciers during the Little Ice Age, which was the last major glacier expansion 400-700 years ago. They found that these glaciers began losing ice 10 times faster during the modern era.  In fact, the glaciers have shrunk from a peak of nearly 11,000 square miles to around 7,500 square miles today.   

This exceptional acceleration of melting of the Himalayan glaciers could have significant implications.  Hundreds of millions of people rely on Asia’s major river systems for food and energy, and depend on these glaciers to feed rivers during the dry seasons.  These rivers include the Brahmaputra, Ganges, and Indus.  The changing global climate could disastrously impact water resources and livelihoods of the Greater Himalayan region.

According to the research team, people living in these regions have already seen changes that are unlike anything witnessed for centuries.  This study is the latest to confirm that these changes are accelerating and pose a significant threat to entire nations and regions. 

**********

Web Links

Himalayan glaciers melting at ‘exceptional rate’

Photo, posted March 13, 2018, courtesy of Sarunas Burdulis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Threat From Thwaites | Earth Wise

By Leave a Comment

The Thwaites Glacier in Antarctica is the widest glacier in the world. It is about 80 miles across and in places extends to a depth of about 2,600 to 3,900 feet.  The glacier is roughly the size of Florida, and it currently contributes 4% of annual global sea level rise as it continues to retreat from a warming ocean.

The International Thwaites Glacier Collaboration is a team of nearly 100 scientists dedicated to studying the glacier.  According to the scientists, Thwaites has doubled its outflow speed within the last 30 years.  The glacier in its entirety holds enough water to raise global sea levels by over two feet, which would be catastrophic.

A third of the glacier flows more slowly than the rest because it is braced by a floating ice shelf that is held in place by an underwater mountain.  The concern is that the brace of ice slowing the glacier may not last for long.

Beneath the surface, warmer ocean water is attacking the glacier from all angles.  The water is melting the ice directly beneath the glacier causing it to lose its grip on the underwater mountain.  Massive fractures have formed and are growing.

Warm water is also a threat for what is called the grounding zone, which is the area where the glacier lifts off the seabed. There are many possible scenarios under which there could be a major ice loss from the glacier.  It is unclear how quickly it could occur.  It might take decades, or it could be centuries.  The threat is large enough and real enough that continued observation and research is essential.

**********

Web Links

The Threat from Thwaites: The Retreat of Antarctica’s Riskiest Glacier

Photo, posted October 16, 2012, courtesy of J. Yungel / NASA Ice via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Whales As Ecosystem Engineers | Earth Wise

By Leave a Comment

Researchers from Stanford University have been studying the role of large whales on ocean ecosystems with some surprising results.

From 1910 to 1970, people killed about 1.5 million baleen whales in the waters surrounding Antarctica.  The whales were hunted for their blubber, baleen, and meat.  Baleen is the filtering fringe that certain whales use instead of teeth to capture food from the ocean.  A primary food source for these whales is krill, small shrimp-like creatures.   One would assume that the decimation of the baleen whale population in the Southern Ocean would have led to a surge in krill populations.  But the new research has found that the opposite is the case.

The precipitous decline of large marine mammals has negatively impacted the health and productivity of ocean ecosystems.

New high-tech tagging devices that attach to whales for brief periods allow researchers to record their movements and activities.  For the first time, it has been possible to accurately determine how much krill whales actually consume, and the answer is that they eat two to three times as much as previously thought.  Interestingly, the same technology shows that fish-eating whales like humpbacks eat somewhat less than previously thought.

Baleen whales are essentially mobile krill processing plants.  They eat the krill, digest it, and produce iron-laden excretions that are needed by phytoplankton, which comprise the bottom of the food chain that nourish krill and other small creatures.  With fewer whales, there is less nourishment for the krill.  In fact, based on the new data, estimates are that the historic abundance of krill in the Southern Ocean had to be about five times what it is today.

Whales are important ecosystem engineers.

**********

Web Links

Stanford researchers find whales are more important ecosystems engineers than previously thought

Photo, posted November 18, 2010, courtesy of Dr. Brandon Southall, NMFS/OPR via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Global Flood Risk From Melting Ice | Earth Wise

By Leave a Comment

Approximately 10% of the land area on Earth is covered by ice.  This includes glaciers, ice caps, and the ice sheets of Antarctica and Greenland.  Nearly 70% of all fresh water on earth is locked away in ice.  If all this land ice were to melt, global sea levels would rise by more than 200 feet. 

According to new research led by researchers at the University of Leeds in the U.K., global warming is causing extreme ice melting events in Greenland to become more frequent and more intense over the past 40 years, leading to an increased risk of flooding worldwide.   

According to the findings, which were recently published in the journal Nature Communications, approximately 3.85 trillion tons of ice has melted from the surface of Greenland and into the ocean during the past decade alone.  That’s enough melted ice to cover all of New York City with nearly 15,000 feet of water. 

Rising sea levels threaten the lives and livelihoods of those living in coastal communities around the world.  Beyond the obvious risk of flooding in low-lying areas, rising seas also disrupt marine ecosystems that many coastal communities rely on for food and work.       

Rising sea levels can also alter patterns of ocean and atmospheric circulation, which in turn affect weather conditions around the planet.

Estimates from models suggest that melting ice from Greenland will contribute between 1 inch and 9 inches to global sea level rise by 2100. 

These findings are just another reminder of how we need to act urgently to mitigate climate change if we want to prevent the worst-case scenarios from becoming reality. 

**********

Web Links

Increased frequency of extreme ice melting in Greenland raises global flood risk

Photo, posted April 21, 2017, courtesy of Markus Trienke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Giant Breakaway Iceberg | Earth Wise

By Leave a Comment

Scientists have been closely monitoring multiple cracks and chasms that have formed in the 500-foot-thick Brunt Ice Shelf in Antarctica over the past few years.  In late 2019, a new crack was spotted in a portion of the shelf north of an area known as the McDonald Ice Rumples.  The rift was monitored by satellite imaging and was seen by February as moving about 15 feet a day.

In the early hours of February 26th, the crack widened rapidly before finally breaking free from the rest of the floating ice shelf.  News reports around the world have described the massive 500-square-mile iceberg by comparing it to the size of well-known cities:  1.5 times the size of greater Paris, 10 times the size of San Francisco, twice the size of Chicago, nearly the size of Greater London, and so on.

Antarctica is known for churning out some enormous bergs.  The new iceberg, which has been named A-74, is huge, but doesn’t compare to the iceberg A-68 that calved from the Larson C Ice Shelf in 2017.  That one was almost five times larger.

The calving of A-74 does not pose a threat to the presently unmanned British Antarctic Survey’s Halley VI Research Station, which was repositioned in 2017 to a more secure location after the ice shelf was deemed to be unsafe.  The section where the station now sits is still holding on, but when it eventually breaks, it will likely create a berg nearly 700 square miles in size.

It remains to be seen what will become of the new iceberg.  Most likely, it will eventually get caught up in the Weddell Gyre, a clockwise-rotating ocean flow in the Southern Ocean that covers an area more than half the size of the US.

**********

Web Links

Breakup at Brunt

Photo, posted October 27, 2016, courtesy of NASA/Nathan Kurtz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Can We Tow Icebergs To Use Their Water? | Earth Wise

By Leave a Comment

At any given time, there are thousands of icebergs adrift in Antarctica that are hundreds or even thousands of feet across.  For at least fifty years, there has been speculation about whether such icebergs could be towed from the Antarctic to places experiencing freshwater shortages.  The feasibility of such a scheme is still the subject of studies that nowadays include sophisticated computer modeling.

Places like the Persian Gulf, Cape Town, South Africa, and Perth, Australia all experience water shortages and could benefit tremendously from having a large iceberg towed to their waters.

How big an iceberg would it take to quench the thirst of a city like Cape Town?  Computer models show that an iceberg 2,000 feet long and 650 feet thick could produce enough water to supply the city for more than a year.  However, with water temperatures in the 60s in the area, even such a large iceberg would melt away within weeks.  So, to get enough water for a year, it would require a much larger iceberg – one at least a couple of miles long.

Daunting problems include figuring out how many and what sort of ships would be required.  An alternative to such giant icebergs would be finding a way to insulate the icebergs so they don’t melt as quickly, thereby allowing much smaller and more towable icebergs to be harvested.

Beyond these issues, there are the ecological issues of the effects of huge amounts of very cold fresh water affecting local marine ecosystems. 

Despite a wide range of challenges, there is continued interest in the idea of using icebergs as a source of very pure fresh water.  In an increasingly thirsty world, it might someday actually happen.

**********

Web Links

Can icebergs be towed to water-starved cities?

Photo, posted November 1, 2007, courtesy of M A Felton via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What’s Killing Orcas? | Earth Wise

By Leave a Comment

With their characteristic tall dorsal fins and black and white color patterns, orcas are one of the ocean’s most iconic species.  Measuring up to 32 feet long and weighing as much as 6 tons, orcas have one of the largest geographic distributions of any species.  They live in all latitudes, in all oceans, from the Arctic to Antarctica.    

While they are often referred to as killer whales, orcas are actually not whales at all.  Orcas are the largest dolphin species and one of the most powerful predators on the planet. 

But human interference has made life significantly more difficult for orcas in recent years.  According to pathology reports on more than 50 orcas stranded over nearly a decade in the northeast Pacific and around Hawaii, the predators face a myriad of mortal threats.  Many of those threats stem from human interactions. 

Researchers from the British Columbia Ministry of Agriculture analyzed these orca pathology reports in a new study, which was recently published in the journal PLOS ONE,.  Of 52 orcas stranded between 2004 and 2013, causes of death were determined for 42%. For example, one orca died after receiving a halibut hook injury. Two orcas died from the blunt force trauma of vessel strikes. While there was no singular common cause of death, the study found a common theme:  human-caused deaths occurred in every age class – from juveniles to adults.

The researchers also note that humans aren’t just indirectly hurting orcas with things like lack of salmon or legacy toxins.  Humans are also directly killing killer whales with boat strikes and fishing gear.   

These findings will help establish a baseline of information to assess future orca conservation efforts. 

**********

Web Links

What’s killing killer whales?

Photo, posted July 5, 2009, courtesy of Rennett Stowe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Antarctica’s Hot Summer | Earth Wise

By Leave a Comment

The Southern Hemisphere’s recent summer brought drought, heatwaves and bush-fires that ravaged Australia.  At the same time, Antarctica experienced a summer of extreme weather.

In East Antarctica, the Casey research station in the Australian Antarctic Territory had its first heatwave event, recording extreme maximum and minimum temperatures over three consecutive days in January.  Record high temperatures were also reported at bases on the Antarctic Peninsula.

The Casey station recorded a record high maximum temperature of 49 degrees Fahrenheit and a record overnight low of 36 degrees.  In February, Brazilian scientists reported a high temperature of 69 degrees at Marambio, an all-time record for Antarctica.

Ecologists say that the hot summer would most likely lead to long-term disruption of local populations, communities, and the broader ecosystem.  That disruption could be both positive and negative.

Most life in Antarctica exists in small ice-free oases and depends on melting snow and ice for a water supply.  Melt water from the warming temperatures will lead to increased growth and reproduction of mosses, lichens, microbes and invertebrates.

However, excessive flooding can dislodge plants and alter the composition of communities of invertebrates and microbial mats. If the ice completely melts early in the season, then ecosystems will suffer drought for the rest of the season.

Extreme events often have impacts for years after the event.  There will be long-term studies of the areas affected by the recent Antarctic heat wave. Such extreme events associated with global climate change are predicted to increase in frequency and impact, and even the most remote areas of the planet are not immune to them.

**********

Web Links

Antarctica’s summer of extreme heat

Photo, posted January 30, 2014, courtesy of Andreas Kambanis via Flickr

Earth Wise is a production of WAMC Northeast Public Radio.

The Rising Threat Of Rising Seas | Earth Wise

By Leave a Comment

Global sea level rose by about 6 inches during the 20th century.  It is currently rising more than twice as fast and accelerating.  The rate of rise was 2.5 times faster from 2006 to 2016 than it was for nearly all of the 20th century.

Sea level rise occurs when glaciers and ice sheets lose mass.  Much of that meltwater comes from Greenland and Antarctica.  But levels also rise because, as water warms, it expands.  Added to that are the effects of human activities such as groundwater depletion and a geological phenomenon called isostatic adjustment that is going on in parts of the East Coast where the land is actually sinking.

In Atlantic Canada, sea level rise is outpacing the global average and has already led to boardwalks swamped by swelling tides, drowned forests, submerged wharfs, and threatened historic shoreline buildings.

Recent research suggests that globally, land now occupied by 300 million people could be affected by floods at least once a year by 2050 unless carbon emissions are significantly reduced, and coastal defenses strengthened.  (This new figure is more than three times higher than earlier estimates).

Researchers at Dalhousie University in Nova Scotia are studying nature-based strategies for mitigating the effects of the rising seas.  These include conserving or restoring coastal ecosystems like dunes, wetlands, and reefs which could provide protection at a lower cost than building seawalls and other man-made obstacles.  Wetlands, for example, can reduce the force of waves and act as obstacles to storm surges, while also trapping sediment and stemming erosion.  Wetlands also serve as important carbon stores, but it is estimated that roughly half of the world’s coastal wetlands have been lost over the past 100 years to human activity and extreme weather events.

**********

Web Links

The Looming Threat of Rising Sea Levels – And What We Can Do About it

Photo, posted February 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bad News For Penguins

By Leave a Comment

The second-largest breeding colony of emperor penguins in Antarctica, located in the Waddell Sea, has experienced “catastrophic breeding failure” for the past three years.  Nearly all of the colony’s chicks have failed to survive due to the breakup of sea ice, according to a new study published in the journal Antarctic Science.

The colony was once home to 14,000 to 25,000 breeding pairs, which represents as much as 9% of the global emperor penguin population.  Emperor penguins are the tallest and heaviest of all living penguins, reaching up to 4 feet in height and weighing between 50 and 100 pounds.  They are the only penguin species that breeds during the Antarctic winter and their lengthy treks to breeding colonies have been the subject of numerous films and television shows.

Sea ice at Halley Bay in Antarctica had been stable and reliable for nearly 60 years but stormy weather in 2016 driven by El Nino conditions, strong winds, and record low ice extent caused the ice on which penguin chicks gather to break up.  This happened again in 2017 and 2018.  By last year, just a few hundred adult pairs were present at the breeding site and almost no chicks survived the ice breakup.

Researchers say that they have never seen a breeding failure on a scale like this in 60 years of studying the colonies.  On a more positive note, while the population of the Halley Bay site has collapsed, the Dawson-Lambton breeding area – located about 34 miles away – has actually seen significant growth over the past four years.  While this is encouraging, the growth at Dawson-Lambton does not fully compensate for the losses at Halley Bay, which was once considered relatively safe from the impacts of climate change.

**********

Web Links

Emperor Penguin Colony Experiences “Catastrophic Breeding Failure”

Photo, posted February 22, 2011, courtesy of Krishna via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Antarctic Warming

By Leave a Comment

East Antarctica is the coldest place on Earth.  It makes up two-thirds of the continent, is home to the South Pole, and has vast ice sheets that have been around for tens of millions of years and are nearly three miles thick in places.  Temperatures there hover around 67 degrees below zero.  In 2010, a few spots on East Antarctica’s polar plateau reached a record-breaking 144 degrees below zero.

But almost unbelievably, parts of the East Antarctic seem to be melting.

Scientists are seeing worrying signs of ice loss in the East Antarctic.  Glaciers are starting to move more quickly and are dumping their ice into the Southern Ocean.  Satellite images show the fast-moving ice.  The biggest glacier – the Totten Glacier – alone contains enough ice to raise global sea levels by over 12 feet.

The Antarctic as a whole contains about 90% of the planet’s ice.  In theory, if it all melted, it would raise global sea levels by an average of 200 feet.

The growing concerns about eastern Antarctica are not that its interior plateau will soon start to melt.  It is still extremely cold there and should stay that way for a long time.  But its edges, which are in contact with warming ocean waters, are the real worry.  As the region’s ice shelves, which float atop the Southern Ocean, erode, the vast glaciers behind them could rapidly accelerate their slide into the sea.

Today, satellites show huge glaciers moving rapidly toward the coast, with wide rivers of ice sometimes moving several miles a year.  In the face of rapid change and limited data, it is difficult to predict what the Antarctic will do in the future.  But it doesn’t look good.

**********

Web Links

Polar Warning: Even Antarctica’s Coldest Region Is Starting to Melt

Photo, posted January 3, 2013, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)