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The oceans are warming faster

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A new study has shown that the rate of ocean warming has more than quadrupled over the past 40 years.  The study, by researchers at the University of Reading in the UK, helps to explain why there have been unprecedented ocean temperatures in 2023 and 2024.

Global ocean temperatures hit record highs for 450 days straight in 2023 and early 2024.  Some of this unusual warmth came from the El Niño that was taking place at the time, but the rest of the increased temperature came from the sea surface warming up more quickly over the past 10 years than in previous decades.  In the late 1980s, ocean temperatures were rising at a rate of 0.06 degrees Celsius per decade.  According to the recent research, they are now increasing at 0.27 degrees per decade.

The acceleration of ocean warming is driven by growth in the Earth’s energy imbalance, meaning that more energy from the sun is being absorbed by the Earth than is escaping back into space.  This energy imbalance has roughly doubled since 2010 as a result of two factors:  increasing greenhouse gas concentrations in the atmosphere and reductions in the Earth’s albedo.

Earth’s albedo, the measure of how much sunlight is reflected back into space, has been declining since the 1970s, primarily due to the decrease in snow and ice cover, especially in the Arctic. 

The overall rate of ocean warming observed over recent decade is likely to only increase.  This underscores the urgency of reducing fossil fuel burning to avoid even more rapid temperature increases in the future.

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Ocean-surface warming four times faster now than late-1980s

Photo, posted January 18, 2007, courtesy of Alexey Krasavin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Polar bear population decline

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Researchers from the University of Toronto have directly linked the population decline in polar bears living in Canada’s Western Hudson Bay to climate change.  Between 1979 and 2021, the polar bear population in this region has declined by nearly 50%.

The monitoring data over this period shows that the average size of polar bears has declined, the size of cub litters has dropped, and cub survival rates are reduced.

The primary factor is the declining amount and duration of sea ice.  When there is less ice, bears have less feeding time and less energy overall.  The loss of sea ice means that bears spend less time hunting seals and more time fasting on land.  The lack of food leads to reduced reproduction, cub survival, and, ultimately, population decline. 

The average body mass of adult females has dropped by 86 pounds and of cubs by 47 pounds.  With shorter hunting periods and less food, mothers produce less milk.  Not only have cub litter sizes dropped over the monitoring period, but mothers are keeping their cubs longer because they are not strong enough to live on their own.  The bottom line is that the survival of cubs directly impacts the survival of the population.

Western Hudson Bay is considered to be a bellwether for polar bear populations globally.  It is one of the southernmost populations of polar bears and it has been monitored for a long time.  With the Arctic warming at a rate four times faster than the global average, polar bear populations in other Arctic regions are likely to be experiencing similar declines. 

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Polar bear population decline the direct result of extended ‘energy deficit’ due to lack of food

Photo, posted October 23, 2015, courtesy of Anita Ritenour via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cold spells and global warming

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January saw some major bouts of subfreezing temperatures across much of North America and significant snowfall in places like Pensacola, Florida and New Orleans.  This spate of frigid weather undoubtedly prompted many people to question whether global warming is really happening.  But such cold spells quite likely are not happening in spite of global warming, but actually as a result of it.

The polar jet stream is a slim band of westerly winds that circles the Arctic.  It is formed where cold air from the north meets warmer air to the south.  As the planet warms, the Arctic has been heating up nearly four times faster than the rest of the planet, which narrows the difference in temperature between the northern air and southern air.  The result is that the jet stream is weaker and more meandering, which allows frigid air to reach further south.

The polar vortex is a whirling mass of cold air that extends across the Arctic.  It is stronger in the winter when the Northern Hemisphere leans away from the sun.  The polar jet stream normally holds on to the vortex and keeps it far to the north.  But when the jet stream gets wobbly, this mass of cold air can break out and travel south, even to places like Florida, Louisiana, and Texas.

The planet as a whole is warming, and the Arctic is warming even faster.  But there will still be plenty of ice, snow, and frigid air in the Arctic winter for decades to come.  As the behavior of the polar jet stream gets increasingly erratic, there may well be more frequent episodes of plunging temperatures in areas unaccustomed to them.

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Severe Cold Spells May Persist Because of Warming, Not in Spite of It

Photo, posted January 5, 2025, courtesy of Dermot O’Halloran via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The human footprint on Earth

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The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it.  But the impact of human activities on our planet continues to grow.  Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Agriculture is a major part of it.  Farms and pastures take up almost half of the world’s habitable land – land not covered by ice or desert.  Greenhouses have recently proliferated tremendously and now cover 3.2 million acres, an area the size of Connecticut, and they even have effects on local climates.

More than half of the world’s population now lives in cities, which are expanding rapidly.  Enormous cities in Asia are changing the landscape in places like Thailand and Indonesia.  Apart from taking up lots of land, many of the world’s cities are immersed in clouds of air pollution that they generate.

Greenhouse gas emissions continue to grow, and temperatures continue to rise.  The effects of this on the planet are increasingly evident.  Seas are rising, ice is melting, glaciers shrink away, and wildfires continue to burn.  The massive wildfires in and around Los Angeles have made major changes in the local landscape.  Rising seas have flooded coastal wetlands and elsewhere, rivers and lakes have shrunk.

There are also human impacts visible from space that represent positive signs.  Large solar arrays supply the cheapest form of energy in most parts of the world and the number and size of solar installations are at a record high.   These solar installations provide some hope that global warming can be slowed.

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The Growing Human Footprint on Earth, as Seen from Space

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

National drought

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Climate change brings with it many kinds of extreme weather.  It isn’t just higher temperatures.  It is changing patterns of weather and weather events that are rare or even unprecedented.

Late October saw drought conditions throughout almost the entire United States.   Only Alaska and Kentucky did not have at least moderate drought conditions.

The previous four months were consistently warmer than normal over a large area of the country.  When that period started, about a quarter of the country was at least somewhat dry, but in late October, 87% of the country was dry.

Droughts in many parts of the U.S. and in places around the world are becoming more frequent, longer in duration, and more severe. 

Residents of New York City were urged to start conserving water.  This October was the driest October since record keeping began in 1869.  The upstate reservoirs that supply New York’s water were below two-thirds full.  They are normally more than three-quarters full in the fall.

Even the Southeast, which received huge amounts of rain from Hurricane Helene, is experiencing drought.  Not much rain had fallen since that storm and warmer temperatures mean more evaporation and drier soils.

Drought is not just a lack of precipitation.  Drought conditions are driven by abnormally high temperatures that remove moisture from the atmosphere and the ground.

Whether widespread drought conditions will persist is unknown.  If a predicted La Niña condition develops in the tropical Pacific, drought conditions in the southern half of the country could get worse, but the Northeast could see lots of rain and snow.

To have nearly the entire country experiencing drought conditions is pretty rare.  But unusual weather is becoming the new normal.

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In a Record, All but Two U.S. States Are in Drought

Photo, posted May 21, 2024, courtesy of Adam Bartlett via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Shrinking polar ice

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Arctic sea ice has shrunk to near-historic lows during this Northern Hemisphere summer.  The minimum extent for the year occurred on September 11th.  Ice cover in the Arctic Ocean has been shrinking and thinning for more than 40 years.  The amount of frozen seawater in the Arctic goes up and down during the year as sea ice thaws and regrows between seasons.

This year, the minimal extent of sea ice shrank to 1.65 million square miles.  That’s about 750,000 square miles less than the average for late summer over the years between 1981 and 2010, representing a decrease of more than 30%.  The all-time low of 1.31 million square miles was actually set in 2012.  Sea ice coverage can fluctuate from year to year, but it has trended downward since it has started being tracked in the late 1970s.  The loss of sea ice has averaged about 30,000 square miles per year.

Sea ice extent has not only been shrinking; the ice has been getting younger and thinner.  Presently, the overwhelming majority of ice in the Arctic Ocean is first-year ice, which is thinner and less able to survive the warmer months.  There is far less ice that is three years or older.

Meanwhile, sea ice in the southern polar regions was also low this year.  In the sea around Antarctica, scientists are tracking near record-low sea ice at a time when it should have been growing extensively during the darkest and coldest months in the Southern Hemisphere.

Polar ice loss compounds polar ice loss.  The loss of sea ice increases heat in the polar regions, where temperatures have risen about four times more than the global average.

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Arctic Sea Ice Near Historic Low; Antarctic Ice Continues Decline

Photo, posted September 15, 2016, courtesy of Mario Hoppmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Antarctic greening

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The Antarctic Peninsula, like other polar regions, is warming faster than the rest of the world.  Ocean heatwaves and ice loss are becoming more common and more severe.

New research by the universities of Exeter and Hertfordshire in the UK along with the British Antarctic Survey used satellite data to assess how much the Antarctic Peninsula has been greening in response to climate change.  The Antarctic Peninsula is an 800-mile extension of Antarctica toward the southern tip of South America.

The study found that the area of vegetation cover across the Peninsula increased from less than one square kilometer in 1986 to almost 12 square kilometers in 2021.  This greening trend accelerated by more than 30% in the period 2016-2021 relative to the entire 1986-2021 period.

An earlier study also showed that the rates of plant growth on the Antarctic Peninsula has increased dramatically in recent decades.  The landscape is almost entirely dominated by snow, ice, and rock, with only a tiny fraction supporting plant life.  The plants found on the Peninsula – mostly mosses – grow in some of the harshest conditions on earth.  But that tiny fraction has greatly increased, showing that this isolated wilderness is being altered by climate change. 

The sensitivity of the Antarctic Peninsula’s vegetation to the changing climate is evident and as warming continues, there could be fundamental changes to the biology and landscape of this unique and vulnerable region.

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Antarctic ‘greening’ at dramatic rate

Photo, posted June 2, 2018, courtesy of Murray Foubister via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rivers are drying up

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According to a new U.N. report, the world’s rivers had their driest year in at least three decades.  Record heat and droughts in many places contributed to low levels of water in many of the world’s rivers.

The world faces problems of either too much or too little water. The warming climate has fueled both powerful storms with heavy rainfall and intense droughts around the globe. 

Last year was the hottest year on record, and it’s a record that is unlikely to last long.  The Mississippi River and Amazon River basins were at all-time lows.  Major rivers with headwaters in the Himalayas – the Ganges, Brahmaputra, and Mekong Rivers – were all unusually dry.

According to the World Meteorological Organizations State of Global Water Resources Report, nearly half of the nearly 1,000 rivers tracked around the world had below-normal levels of water.  Only 17% had above-average levels.  Over the past 32 years, on average only a quarter of the rivers monitored had below-normal water levels and last-year’s 45% was the largest ever.

Last year’s severe heat shrank glaciers that are a crucial source of meltwater that feeds rivers.  Glaciers lost more ice last year than they have in at least 50 years.

More than half of the world’s population lives within a couple of miles of a body of fresh water.  The places with the highest population densities around the world are almost all near large rivers.  Rivers provide freshwater for irrigation, consumption, and transportation and are an important source of energy. Historically, they have played an important role in the development of human society.  The shrinking of rivers is a big deal.

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World’s Rivers Are Driest They Have Been in Decades

Photo, posted August 22, 2023, courtesy of Radek Kucharski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The doomsday glacier

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The Thwaites Glacier is an enormous Antarctic Glacier.  Its area is larger than that of Florida – in fact, larger than 30 other U.S. states – and it is melting.  It has been retreating for 80 years but has accelerated its pace in the past 30.  Its shedding of ice into the ocean already contributes 4% of global sea level rise.  If it collapsed entirely, it would raise sea levels by more than 2 feet.  For this reason, it has been dubbed the Doomsday Glacier.

A team of scientists has been studying it since 2018 in order to better understand what is happening within the glacier. They sent a torpedo-shaped robot to the glacier’s grounding line, which is the point at which the ice rises up from the seabed and starts to float.  The underside of Thwaites is insulated by a thin layer of cold water.  However, at the grounding line, tidal action is pumping warmer sea water at high pressure as far as six miles under the ice.  This is disrupting the insulating layer and is speeding up the retreat of the glacier.

The potential collapse of the glacier is not even the only massive risk it poses.  It also acts like a cork, holding back the vast Antarctic ice sheet.  If that ice sheet were ever to collapse, sea levels could rise 10 feet.

A critical unanswered question is whether the ultimate collapse of Thwaites Glacier is already irreversible.  There are regular heavy snowfalls that occur in the Antarctic which help replenish ice loss.  Whether nations’ progress in slowing climate change can change the balance between ice accumulation and ice loss on the glacier remains to be seen.

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‘Doomsday’ glacier set to melt faster and swell seas as world heats up, say scientists

Photo, posted January 3, 2022, courtesy of Felton Davis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Svalbard is melting

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Svalbard is a Norwegian archipelago between mainland Norway and the North Pole. It is one of the world’s northernmost inhabited areas and is a popular attraction for tourists.  Svalbard is famous for rugged, remote terrain of glaciers and frozen tundra sheltering polar bears, Svalbard reindeer, and Arctic foxes. The Northern Lights are visible during winter, and its summer features the “midnight sun”—sunlight 24 hours a day.  It is the home of the Svalbard Global Seed Vault, which provides safe, free, and long-term storage of seed duplicates from all gene banks and nations around the world. 

Over half of Svalbard’s land area is covered with ice and accounts for about 6% of the planet’s glaciated area outside of Greenland and Antarctica.  But Svalbard is also one of the fastest-warming places on Earth.

It has suffered extreme episodes of melting this summer, brought on by exceptionally high air temperatures.  In late July and early August, temperatures hovered around 7 degrees Fahrenheit above average for this part of the Arctic Circle, causing snow and ice to rapidly melt.

According to scientists, Svalbard’s ice caps broke their all-time record for daily surface melt on July 23rd, shedding nearly half a foot of water equivalent that day, a rate five times larger than normal. 

On August 11th, the high temperature in Longyearbyen, Svalbard’s capital city, reached 68 degrees, the highest August temperature on record and 4 degrees above the previous monthly record.  Svalbard experienced its warmest summer on record in 2023.

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Svalbard Melts

Photo, posted September 21, 2016, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Glaciers in Venezuela

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There are nearly 200,000 glaciers in the world.  About 91% of them are in Antarctica and 8% in Greenland.  The rest are scattered across nearly 50 countries.  The non-polar country with the most glaciers is actually Pakistan, which has over 7,200 of them.  But as the world continues to warm, glaciers are shrinking back, and many are disappearing altogether.

Venezuela, once home to six glaciers, has become the first country in the Americas to lose all of its glaciers.  Slovenia is considered to be the first country to lose its glaciers in modern times, perhaps as long as 30 years ago.  Glacial thawing has been worsening over the past decade throughout the Andes, which cover parts of Colombia, Venezuela, Bolivia, Ecuador, Peru, Chile, and Argentina.

Five of Venezuela’s glaciers had largely melted away by 2011.  The Humboldt glacier, which is on the highest peak in the Cordillera de Mérida mountain range in Venezuela, has now been declared as too small to be classified as a glacier.  It once covered over a thousand acres; it now has less than 5 acres of ice.  The US Geological Survey defines glaciers as ice bodies extending 25 acres or more.

The loss of glaciers in the Andes has serious consequences for communities that live on their slopes and depend upon glacial melt for water and for energy and food production. 

At least 80% of glaciers worldwide are on track to mostly disappear by the year 2100 because of global warming.  Given that previous forecasts estimated that the Humboldt glacier might last another decade, the prospects for the world’s remaining glaciers are not good.

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Venezuela becomes first nation in the Americas to lose all glaciers

Photo, posted November 11, 2012, courtesy of Tim Snell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Penguin detectives

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Emperor penguins, the tallest and heaviest of all living penguins, are also the most famous, being the subject of a very popular documentary film.  The ongoing loss of sea ice in Antarctica has led to unprecedented breeding failures in emperor penguin colonies. 

Since 2016, Antarctica has seen the four years with the lowest sea ice extent on record.  Between 2018 and 2022, 30% of the 62 known emperor penguin colonies were affected by partial or total sea ice loss.  Current predictions suggest that the population of emperor penguins will fall by 99% by the end of the century.

To monitor remote emperor penguin colonies, researchers use satellite images in which the brown stains of the birds’ guano stand out against the white ice and snow.

Researchers at the British Antarctic Survey have launched the ‘Polar Observatory’ on the online citizen science website Zooniverse to recruit ‘penguin detectives’ to help validate the accuracy of satellite images in assessing penguin populations.

The online app contains drone photos taken over the Snow Hill penguin colony.  The images have been split into more than 300 10-meter squares.  Volunteers are asked to identify any adult and chick penguins in a given picture.  The results will be fed into machine learning algorithms to train the AI systems in automatically counting penguins in future surveys.

The project is a fun opportunity for aspiring conservationists and penguin lovers in general to help learn more about the future of the species.  Interested people can learn more on the Zooniverse website.

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‘Penguin detectives’ required for new counting app

Polar Observatory

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

Earth Wise is a production of WAMC Northeast Public Radio

Climate change and Antarctic meteorites

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Researchers from Switzerland and Belgium have investigated the effects of the warming climate on access to meteorites in Antarctica.  Meteorites are of great scientific interest because they provide unique information about the makeup of our solar system.  Of all the meteorites that people have found, 62.6% of them were found in Antarctica.

Why is this?  It is not because more meteorites land in Antarctica.  Statistically, they can land anywhere on earth.  Most end up in the ocean since the world’s oceans cover 70% of the planet. 

Meteorites in Antarctica are more visible because environmental conditions are favorable for their preservation and their visibility.  The arid and cold Antarctic environment helps to preserve meteorites and the lack of rocks and contrast with ice makes spotting meteorites much easier.  The flow of ice sheets tends to concentrate meteorites in so-called meteorite stranding zones where the dark colored space rocks can be easily detected.

There are an estimated 300,000 to 800,000 meteorites in Antarctica.  When meteorites warm up, they can transfer heat to the ice, which locally melts.  Eventually, the meteorites sink beneath the surface.  A recent study using satellite imagery, climate model projections, and AI predicts that for every tenth of a degree of increase in global air temperature, an average of 9,000 meteorites in Antarctica will disappear from the surface and will no longer be able to be found. 

The study estimates that a quarter of Antarctic meteorites will be lost to glacial melt by 2050.  If warming continues to accelerate, closer to three-quarters of the meteorites on the continent will be lost. 

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Climate change threatens Antarctic meteorites

Photo, posted April 21, 2005, courtesy of Kevin Walsh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Self-heating concrete

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States in the colder parts of the country spend an estimated $2.3 billion a year on snow and ice removal as well as untold millions on repairing roadways damaged by winter weather.  Researchers at Drexel University have been researching a way to extend the service life of concrete surfaces like roadways and to help them maintain a surface temperature above freezing during the winter.

Preventing freezing and thawing as temperatures go up and down and reducing the amount of plowing and salting is a desirable goal.  The Drexel team has developed a cold-weather-resilient concrete mix that is capable of melting snow on its own using only the thermal energy in the environment and not requiring salt, shoveling, or heating systems.

The system uses low-temperature liquid paraffin that turns from its room-temperature liquid state into a solid when temperatures go down.  Incorporating the liquid paraffin into concrete triggers heating when temperatures drop due to the energy released by the phase change.

Tests on slabs of the concrete on the Drexel campus over the past two years recorded 32 freeze-thaw events.  The special slabs maintained a surface temperature between 42 and 55 degrees for up to 10 hours when air temperatures dipped below freezing.

The heating is enough to melt a couple of inches of snow at a rate of a quarter inch an hour.  It’s not enough to melt a heavy snow event before plows are needed, but it can help deice road surfaces and increase transportation safety.  And simply preventing the surface from freezing, thawing, and refreezing can go a long way towards preventing deterioration.  It is promising research toward reducing an ongoing problem in colder climates.

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Drexel’s Self-Heating Concrete Is One Step Closer to Clearing Sidewalks Without Shoveling or Salting

Photo, posted March 16, 2024, courtesy of Ajay Suresh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An ice-free Arctic

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According to a new study by Colorado University, Boulder, the Arctic could see summer days with practically no sea ice as soon as sometime in the next few years.  Earlier predictions for when the first ice-free day in the Arctic could occur were sometime well into the 2030s.

By mid-century, the Arctic is likely to see an entire month without floating sea ice.  This would likely be in September, when ice coverage is at its minimum.  By the end of the century, the ice-free season could last for many months during the year.

Technically, an ice-free Arctic does not mean zero ice in the water.  The working definition is less than 386,000 square miles of ice, which represents less than 20% of what the minimum ice coverage was in the 1980s. In recent years, the coverage has been about 1.25 million square miles.

Sea ice coverage is a big deal because many Arctic animals rely on sea ice for survival, including seals and polar bears.  With warmer ocean water, invasive fish species could move into the Arctic Ocean, upsetting local ecosystems.  Sea ice loss also is a risk for coastal communities because the ice buffers the impact of ocean waves on the coastal land.  As the ice retreats, ocean waves would get bigger, eroding the coasts.

At this point, an ice-free Arctic is basically inevitable, but its annual duration will depend on society’s efforts to reduce carbon emissions.  Lengthy periods of minimal sea ice would transform the Arctic into a completely different environment with global effects that are mostly highly undesirable.  However, Arctic sea ice is resilient and could return fairly quickly if the atmosphere cools down.

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The Arctic could become ‘ice-free’ within a decade

Photo, posted July 9, 2022, courtesy of Reiner Ehlers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Shrinking African glaciers

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We don’t usually associate Africa with glaciers, but the continent has had glaciers on its highest peaks for the past 10,000 to 15,000 years.  Africa’s glaciers are found in three regions:  the Rwenzori Mountains along the border between Uganda and the Democratic Republic of the Congo, Mount Kilimanjaro, and Mount Kenya.  At the turn of the 20th century, there were 43 glaciers scattered across 6 peaks within the Rwenzori Mountains.  In the intervening years, things have greatly changed.

 Since the early 20th century, Africa’s glaciers have shrunk by 90%.  Because all these glaciers are close to the equator, they are especially vulnerable to warming.  According to a new study published in the journal Environmental Research: Climate, in the last two decades, Africa’s glaciers have lost roughly half their area.

This rapid decrease is alarming to climate scientists because they represent a clear indicator of the impact of climate change.  A major factor in the decline of the glaciers is the reduction in cloud cover over the mountains.  Sunshine is melting glaciers and turning ice directly into water vapor even when temperatures are below freezing.  Reductions in snowfall at the same time means that the melting glaciers are not being replenished.

Scientists believe that the tropical glaciers of Africa may all but disappear over the next 25 years.

Roughly three-quarters of the Earth’s freshwater is stored in the world’s more than 200,000 glaciers.  According to scientists, if the world reaches but maintains 1.5 degrees of warming, half of the world’s glaciers could be gone by the end of this century.  If the world continues to warm as it has been without slowing down, more than 80% of the glaciers will disappear.

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Africa’s Tropical Glaciers Have Shrunk by 90 Percent, Research Shows

Photo, posted February 26, 2022, courtesy of Ray in Manila via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenland is greening

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Despite their names, Iceland is very green, and Greenland is very icy.  But in Greenland, that is changing.  Temperatures in the world’s largest island are rising twice as fast as they are in the rest of the world and, as a result, the icy rocky landscape is turning increasingly green.

Satellite records reveal that over the last three decades Greenland has lost 11,000 square miles of ice, which is an area about the size of Massachusetts.  As the ice melts off, tundra and shrublands takes its place.  The ice melt moves sediment and silt and eventually wetlands and fenlands are formed.

Between the late 1980s and the late 2010s, the areas of Greenland covered by vegetation have more than doubled.  The new green areas cover roughly 33,000 square miles, which is an area the size of Maine.

Greenland’s dramatic changes are the result of the warming climate, but in turn, those changes are accelerating climate change.  Land covered with dark green vegetation absorbs more energy from the sun thereby warming the air whereas ice-covered landscapes reflect much of the sun’s energy back into space.  In addition, the rapidly expanding wetlands are a significant source of methane, which traps even more heat in the atmosphere.

Greenland is a poster child for the effects of climate change.  Its glaciers and icecaps are shrinking, glacier-fed lakes are expanding, permafrost lakes are draining, and rivers are transporting vast amounts of sediment and widening.  All of this is going on as its vegetation cover and species diversity is expanding.

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In Icy Greenland, Area Covered by Vegetation Has More Than Doubled in Size

Photo, posted September 20, 2019, courtesy of Amanda via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Little ice on the Great Lakes

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In an average year, the Great Lakes end up about 40% covered in ice.  But this is not an average year.  2023 was the warmest year on record and, in fact, the global temperature was more than 1.5 degrees above the pre-industrial average for the full year.  That hasn’t happened before.  As a result of the record-breaking warmth, as of mid-February, the average ice cover on the Great Lakes was only 5.9%.

Lake Erie and Lake Ontario tied their records for the lowest ice cover, which has been tracked since 1973.  Lake Huron, Lake Michigan, and Lake Superior are at historic lows.  Some parts of the Great Lakes have experienced the winter without any ice cover.

The warming air temperatures have led to rapid ice loss and warming summer temperatures.  According to experts, if the planet continues to warm, more than 200,000 lakes may no longer freeze every winter and 5,700 lakes may permanently lose ice cover by the end of the century.

Studying the Great Lakes is important because their ice melt can be a significant indicator of the progress of global warming.  Decreasing ice cover can affect hydropower generation, commercial shipping and fishing, and have environmental impacts such as the development of plankton blooms.

Since the 1970s, there has been a 5% decline in Great Lakes ice cover per decade.  Unfrozen lakes bring more rain than snow which has environmental, cultural, and societal impacts.  The Great Lakes hold 21% of the world’s freshwater supply and over 30 million people depend on them for drinking water.  They are also linked to over $3 trillion in gross domestic product.

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Great Lakes Winter Ice Cover Averaging Just 5.9%: NOAA

Photo, posted November 7, 2007, courtesy of Jim Sorbie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Polar bears and the changing climate

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The changing climate poses a major threat to polar bear survival.  Polar bears, whose native range lies largely within the Arctic Circle, depend on sea ice for nearly all of their lifecycle functions.  Rising global temperatures are causing this sea ice to disappear.

With less sea ice, polar bears are forced to stay longer on land.  However, according to a new study led by researchers from Washington State University, more time stranded on land leads to a greater risk of polar bear starvation. 

During three summer weeks in Manitoba, Canada, 20 polar bears observed by researchers tried different strategies to maintain energy reserves.  But the research team found that nearly all of them lost weight – losing about 2.2 pounds per day on average.     

Some scientists have speculated that polar bears might be able to adapt to the changing climate by acting more like grizzly bears by either resting or eating terrestrial food.  But the polar bears tried versions of both strategies – with little success.

Polar bears can weigh nearly twice as much as grizzly bears.  To maintain this size, polar bears rely on the energy-rich fat of seals, which they best catch on ice.

In the study, which was recently published in Nature Communications, the researchers found that some polar bears laid down to conserve energy, while others searched on land for food.  But neither the activity nor the lack thereof paid off.  In fact, only one bear out of the 20 gained weight after stumbling across a dead marine mammal on land.

Polar bears across the Arctic are at risk of starvation as the ice-free period continues to grow.

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Polar bears unlikely to adapt to longer summers

Photo, posted November 16, 2015, courtesy of Anita Ritenour via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A wet January

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For the first time in a while, the monthly report on the US climate did not feature record-setting heat.  The average January temperature across the contiguous U.S. was 1.6 degrees above the average, but that only ranked it in the middle third of the climate record.  The diminishing El Niño probably helped.  On the other hand, the global average temperature in January was again the warmest on record – the 8th consecutive record-setting month.

But January still managed to be atypical weatherwise in the U.S. in that the nation’s average precipitation across the country was 3.18 inches – nearly an inch above average – which made it the 10th wettest January in NOAA’s 130-year climate record.  Thirteen states experienced top-ten rainfall amounts.  In late January, record rainfall and flooding hit the southern plains, especially in parts of Texas and Louisiana.  Meanwhile, early February brought historic rainfall and mountain snow to California with a second round later in the month.

All of the rainfall in January has made some difference to drought conditions across the country.  On January 30th, about 23.5% of the contiguous U.S. was In drought, which was 9.5% lower than the beginning of the month.  However, drought conditions expanded or intensified across northern parts of the Rockies and Plains among a few other places.

Outside of the lower-48, Alaska continued to experience historic snowfall conditions.  Between October and the end of January, Anchorage had over 100 inches of snow.

We are living in an era of weather extremes.

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The nation just saw its 10th-wettest January on record

Photo, posted February 8, 2017, courtesy of Paxson Woelber via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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