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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

Renegade geoengineering

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As the dangers of climate change continue to grow, so has interest in geoengineering – deliberate tinkering with the earth’s climate system.  In particular, stratospheric solar geoengineering – releasing aerosols into the stratosphere to reduce the amount of heat from the sun reaching the Earth – is attracting increasing interest.  Scientists at Harvard, Cornell, Colorado State, Princeton, and the University of Chicago are all researching the topic.

Actually doing it on a scale that matters is fraught with peril from unintended consequences of disrupting the delicate interactions between the Earth’s atmosphere, ocean, land, and sea ice. 

Meanwhile, a tiny start-up company in Silicon Valley has raised more than a million dollars in venture capital and is busy releasing balloons full of sulfur dioxide into the atmosphere in the name of combatting global warming.  Furthermore, they are selling so-called “cooling credits” to customers who want to offset their personal carbon emissions.

The aerosol being released is on such a small scale that it can’t possibly have a meaningful effect on temperatures.  There really isn’t scientific analysis guiding or accompanying the work. 

There are no laws prohibiting the dispersal of small amounts of sulfur dioxide in California.  Even if there were, these people could go offshore or elsewhere to do their work.  But this renegade geoengineering highlights a serious issue; namely, that there doesn’t have to be scientific, political, or any other kind of consensus for someone to undertake a potentially catastrophic attempt to alter the climate.  It’s a real worry.

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Silicon Valley Renegades Pollute the Sky to Save the Planet

Photo, posted September 24, 2006, courtesy of Doc Searls via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ocean geoengineering

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As greenhouse gas emissions continue to be dangerously large and the perils of climate change are increasingly apparent, the world is increasingly exploring ways to deliberately intervene in climate systems.  A number of these ideas involve introducing substances into the atmosphere, but there are also ways to tinker with the oceans.

The oceans naturally absorb about a third of the carbon dioxide that humans pump into the atmosphere, mostly by burning coal, gas, and oil.  People are exploring ways to get the ocean to take up even more of the carbon dioxide.  One approach that is gaining traction is known as alkalinity enhancement.  By adding limestone, magnesium oxide, or other alkaline substances to rivers and oceans, it changes their chemistry and makes them soak up more carbon dioxide.

This approach has been around for a while as a way to mitigate acid rain in rivers and has been very successful.  A start-up company in Canada called CarbonRun is building a machine that grinds up limestone and will release the powder it produces into a local river in Nova Scotia.  The limestone in the river will be naturally converted into a stable molecule that will eventually be washed into the seas, where it should remain for thousands of years.

Expanding this approach to oceans faces many challenges including the costs and complexities of obtaining, processing, and transporting vast amounts of limestone to where it is to be released.  There are also potential environmental issues to grapple with.  But CarbonRun and others are moving forward with testing the approach.

In any event, the biggest barrier to ocean alkalinity enhancement is proving that it works.  That effort is underway.

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They’ve Got a Plan to Fight Global Warming. It Could Alter the Oceans.

Photo, posted May 27, 2007, courtesy of John Loo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

And the heat goes on

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August 2024 was the hottest August in the 175-years for which there are global records.  The last full month of summer also wrapped up the Northern Hemisphere‘s warmest summer on record.

The average global surface temperature in August was 62.39 degrees Fahrenheit, which is 2.29 degrees above the 20th century August average.  Furthermore, August was the 15th consecutive month of record-high global temperatures, which is a record in and of itself.

Regionally, Europe and Oceana had their warmest August on record.  Asia had its second-warmest August, and Africa and North America had their third-warmest August.

The summer in the Northern Hemisphere was a record-breaker with a temperature 2.74 degrees Fahrenheit above average.  Thinking about climate goals, this is 1.52 degrees Celsius above average, which is a troubling amount.  Meanwhile, in the Southern Hemisphere, where it was winter in the June-to-August period, it was also the warmest ever with a temperature 1.73 degrees Fahrenheit above average.

Globally, this year to date ranks as the warmest ever recorded with a temperature 2.3 degrees above the 20th-century average.  With a few months to go, the prediction is that there is a 97% chance that 2024 will rank as the world’s warmest year on record.

Other aspects of the global climate system were consistent with these record-breaking temperatures.  The global ocean surface temperature for June through August was the warmest on record. 

These monthly climate reports have an unfortunate similarity:  the heat goes on.

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Earth had its hottest August in 175-year record

Photo, posted June 22, 2021, courtesy of Vicky Brock 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

Warming estuaries

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Estuaries and their surrounding wetlands are bodies of water where freshwater from rivers and streams mixes with salt water from the ocean to create brackish water.  These brackish ecosystems support many unique plant and animal communities around the world. 

But ocean water temperature around the world continues to warm.  In fact, from 1901 to 2023, the average sea surface temperature has increased by 0.14°F per decade, and 2023 was the warmest year on record.

While sea surface temperatures are on the rise, the problem is more pronounced in South Florida’s estuaries.  According to a new study by researchers from the University of South Florida College of Marine Science and the National Park Service, estuaries have experienced rapid warming over the past two decades. 

In fact, the research team found that sea surface temperature in four estuaries in South Florida – Florida Bay, Tampa Bay, St. Lucie Estuary and Caloosahatchee River Estuary- has risen around 70% faster than the Gulf of Mexico, and 500% faster than the global oceans. 

Their findings, which were recently published in the journals Environmental Research Letters and Estuaries and Coasts, paint a troubling picture for the marine life that calls South Florida’s estuaries home.

The research team has speculated about the possible causes of the rapid rate of warming, including evaporation, water capacity, and residence time, but no single factor has been revealed as dominant. 

The researchers hope to partner with colleagues at the Florida Fish and Wildlife Conservation Commission and NOAA to explore the potential impacts of water temperatures on seagrass and coral populations in South Florida.

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Estuaries in South Florida are warming faster than the Gulf of Mexico and global ocean

What is an estuary?

Photo, posted August 18, 2016, courtesy of City of St. Pete via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

2023: A year of extreme climate

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There have already been all sorts of extreme weather this year in many parts of the world and undoubtedly there will be more to talk about in the coming months.  But the American Meteorological Society has recently published its State of the Climate report for 2023 and it was a year for the record books.

In 2023, the Earth’s layers of heat-reflecting clouds had the lowest extent ever measured.  That means that skies were clearer around the world than on average, a situation that amplifies the warming of the planet.  Since 1980, clouds have decreased by more than half a percent per decade. 

The most dramatic climate effect last year occurred in the world’s oceans.  About 94% of all ocean surfaces experienced a marine heatwave during the year.  The global average annual sea surface temperature anomaly was 0.13 degrees Celsius above the previous record set in 2016.  This is a huge variation for the ocean.  Ocean heatwave conditions stayed in place for at least 10 months in 2023 in vast reaches of the world’s oceans.  Ocean heat was so remarkable that climate scientists are now using the term “super-marine heatwaves” to describe what is going on. 

There were many other ways in which 2023 experienced weather extremes.  July experienced a record-high 7.9% of the world’s land areas in severe drought conditions.  During the year, most of the world experienced much warmer-than-average conditions, especially in the higher northern latitudes.  These unprecedented changes to the climate are unlikely to be one-time occurrences; 2024 is likely to be another one for the record books.  

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New Federal Report Details More of 2023’s Extreme Climate Conditions

Photo, posted May 27, 2021, courtesy of Wendy Cover/NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Deep sea mining

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Deep sea mining is the extraction of minerals from the ocean floor at depths greater than 660 feet and as much as 21,000 feet below the surface.  Active or extinct hydrothermal vents on the ocean floor create sulfide deposits which collect metals such as silver, gold, copper, manganese, cobalt, and zinc.  This forms polymetallic nodules – potato-sized rocklike deposits containing these valuable minerals.  There are literally trillions of these things scattered over wide areas of ocean floor.  The largest of these deposits are in the Pacific Ocean between Hawaii and Mexico in the Clarion Clipperton Fracture Zone.

Mining companies argue that land-based sources for valuable metals are running out and are critically needed for green technologies like batteries for electric vehicles and manufacturing solar panels and wind turbines.  They also claim that mining in the deep sea will be less environmentally damaging than land-based mining.

The deep sea is viewed by many as kind of a watery desert but there are actually diverse and rich ecosystems down there.  Most of the animals living in the depths are tiny, but that doesn’t make them any less important.  Many can live for a very long time.  Some invertebrates live for thousands of years.

There are currently no commercial deep sea mining operations underway.  Many countries have outlawed them.

The deep seas are the last mostly unexplored part of the Earth.  Deep sea mining will unquestionably be highly destructive to these environments.  We don’t really know what the impact of widespread deep sea mining might be, but the world continues to edge ever closer to allowing it to happen.

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Can We Mine the World’s Deep Ocean Without Destroying It?

Photo, posted March 30, 2018, courtesy of the NOAA Office of Ocean Exploration and Research via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How warm is It?

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As of June, the world had seen 13 consecutive months of record-breaking heat.  The average global temperature over the last 12 of those months measured 1.5 degrees Celsius warmer than the preindustrial era. This means that the world has at least temporarily exceeded the temperature target set forth in the Paris Climate Agreement.

Does this mean that climate change has gotten to the point where keeping temperatures below that goal is no longer possible? Not necessarily. Temperatures could drop below the 1.5-degree level in the near future.

The world has certainly been warming as a result of climate change, but the spike in temperature for the past year has also been driven by an El Niño condition in the Pacific, which leads to warmer temperatures.  How much of the warming is a result of each factor is not known.

But scientists say that El Niño has ended in June and a La Niña condition is likely to take shape between August and October. This would lead to cooler temperatures in many places.

Despite the extensive and lingering heatwaves in the US in July, on a global scale, temperatures have actually started falling in July.  July may end up being the first month since June 2023 to not set a new monthly global temperature record.  Nevertheless, the long streak of record-high temperatures is no statistical anomaly.  It is indicative of a large and continuing shift in the climate.   Whether conditions in the Pacific produce an El Niño or a La Niña, the steady long-term warming will continue as long as human-generated carbon emissions continue.

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How Bad Is Warming? La Niña May Reveal

Photo, posted September 19, 2022, courtesy of Paul Sableman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Eliminating plastic shipping pillows

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Anyone who gets packages from Amazon is familiar with the plastic air pillows used to keep products safe in transit.  Amazon uses almost 15 billion of them a year in North America.

Environmentalists have been urging Amazon and other vendors to cut down on the use of plastic packaging. The air-filled plastic pillows are made from plastic film, which is the most common form of plastic litter found in the sea and in seabeds along the shore.  Plastic film can be deadly to wildlife such as sea turtles and sea birds.  Plastic film generally can’t be composted or recycled either.

Recently, Amazon announced that it will replace its plastic pillows with recycled paper filler in all its North American markets – the United States, Canada, and Mexico – which together account for more than 70% of the retailer’s global sales.  It is already making the switch in a big way and is working towards fully removing the plastic materials by the end of the year.

Replacing plastic packaging with paper is a definite improvement.  Paper is recyclable and biodegradable.  It isn’t perfect:  if it ends up in landfills, it can contribute to methane pollution as it biodegrades.  But, on the other hand, paper packaging is more likely to be recycled.

Stemming the tide of plastic waste is an ongoing effort by environmental and consumer groups.  There is pending legislation in New York that aims to reduce the use of plastic packaging by 50% over 12 years by requiring manufacturers to either replace it or pay fees.  The bill cleared the State Senate but has not come up to a vote in the Assembly.  Similar legislation has already been passed in California, Oregon, Maine, and Colorado.

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Amazon Says It Will Stop Using Puffy Plastic Shipping Pillows

Photo, posted November 20, 2018, courtesy of Todd Van Hoosear via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Minerals from seawater

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There are about 18,000 desalination plants around the world that take in 23 trillion gallons of water each year.  The plants produce more than 37 billion gallons of brine – enough to fill 50,000 Olympic-size swimming pools – every day.  Disposing of this brine is an ongoing challenge.  Dumping it into the ocean can damage marine ecosystems.  Inland desalination plants either bury this waste or inject it into wells, adding further cost and complexity to the already expensive process of desalination.

According to researchers at Oregon State University, this waste brine contains large amounts of copper, zinc, magnesium, lithium, and other valuable metals.  A company in Oakland, California called Magrathea Metals has started producing modest amounts of magnesium from waste brine in its pilot projects.  With support from the U.S. Defense Department, it is building a larger-scale facility to produce hundreds of tons of the metal over two to four years. 

Most of the world’s magnesium supply comes from China, where producing it requires burning lots of coal and utilizing lots of labor.  Magrathea’s brine mining makes use of off-peak wind and solar energy and is much less labor intensive.

No large-scale brine mining operations currently exist and when there are some, they might end up having negative environmental impacts.  But in principle, the process should produce valuable metals without the massive land disturbance, acid-mine drainage, and other pollution associated with traditional mining.  Brine mining could turn a growing waste problem into a valuable resource.

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In Seawater, Researchers See an Untapped Bounty of Critical Metals

Photo, posted February 18, 2017, courtesy of Jacob Vanderheyden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Beware of the blob

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For the past 10 years, there have been several occurrences of a vast expanse of ocean stretching from Alaska to California in which water temperatures are as much as 7 degrees Fahrenheit warmer than normal.  Known jocularly as “the Blob,” the phenomenon can last for several years and decimates fish stocks, starves seabirds, creates blooms of toxic algae, prevents salmon from returning to rivers, and displaces sea lions and whales.

Until recently, there was no accepted explanation for this abrupt ocean heating.  Climate change, even combined with natural cycles like El Niños, is not enough to account for it.

In depth analysis by an international team of researchers has found that the extraordinary heating is the result of a dramatic cleanup of Chinese air pollution.  The decline of smog particles, which to some extent shield the planet from the sun’s rays, has accelerated warming and set off a chain of atmospheric events across the Pacific, essentially cooking the ocean.

This is an example of what can be called the pollution paradox in which global warming is actually increased when air pollution is reduced.  Reduced air pollution on the US West Coast has even been identified as a factor contributing to increased wildfires.  However, air pollution causes more than 4 million premature deaths from cancers and respiratory and cardiovascular diseases each year. 

Nobody thinks that we should stop cleaning up the air to slow down global warming.  The only viable solution is to reduce greenhouse gas emissions as rapidly as possible.

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Pollution Paradox: How Cleaning Up Smog Drives Ocean Warming

Photo, posted December 18, 2017, courtesy of SGUP via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Floating cities

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About 40% of the world‘s population lives in coastal regions.  People really like ocean-front property.  But worldwide, rising sea levels mean that more and more people want to live on land that may someday be swallowed up by the sea.

One possible solution to the problem is to build cities on top of the water.  It sounds pretty futuristic and impractical, but it is starting to happen.  There have long been floating communities in places like the Netherlands, but these are for the most part clusters of houseboats moored close together.

But there are far more ambitious projects underway.  The Maldives Floating City, already under construction, will eventually have 5,000 houses located in a lagoon that is a 15-minute boat ride from the capital city of Male.  The housing units will be tethered to the lagoon floor and linked together. 

A new project, located off Busan, South Korea, will combine high and low technology to create a large-scale, on-water town, that can house more than 10,000 people.

The town will be built on enormous concrete platforms suspended on the water.  The platforms float because they are rounded hexagonal boxes that are buoyed up by Archimedes’’ principle.  They can’t sink.  Such structures will attract marine life, providing places for oysters and mussels, for example, to grow. 

The initial development will cover 15 acres and the infrastructure will handle power, water, waste, and even some food.  The goal is even to produce enough energy to provide some to the nearby community.  A bridge will link the community to the land.

The project is scheduled to be completed in 2028.  Future expansion could end up housing 150,000 people.

Floating cities could soon no longer be exotic or futuristic.

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Are Floating Cities the Solution to Rising Seas?

Photo, posted June 5, 2012, courtesy of Raymond Bucko via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Offshore wind and the wake effect

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Electricity demand in the U.S. continues to grow and, in the summer, homes and businesses crank up their air conditioning which drives demand even further.  Many East Coast cities are banking on offshore wind projects that are underway in the Atlantic Ocean to help meet that growing demand.  The first offshore turbines are now producing power off the coasts of Massachusetts and New York.

Electric power utilities need to know how much power they can get from offshore wind farms, and this is not that easy to predict.  Wind is variable, so there is some built-in uncertainty.  But there is also a phenomenon known as the wake effect to contend with.

When wind passes through a series of giant turbines, the ones in front extract some energy from the wind and, as a result, the wind slows down and becomes more turbulent behind the turbines.  So, the downstream turbines get slower wind and may produce less power.

A study by the University of Colorado has modeled this phenomenon for planned wind farms in the Atlantic Coast region and has found that power output could be reduced by over 30%.  Researchers are installing weather monitors and radar sensors in islands off the New England coast to better understand the behavior of the wind in the area and improve prediction models.

The New England grid covers Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. Even with the wake effect, offshore wind is predicted to be able to provide 60% of the electricity needs of the grid, but it is important to be able to accurately predict what it can produce.

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How much energy can offshore wind farms in the US produce? New study sheds light

Photo, posted August 31, 2022, courtesy of Nina Ali via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Marine carbon dioxide removal

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About 30% of the carbon dioxide emitted by human activity is absorbed by the oceans.  As a result, they are getting warmer and more acidic, and the currents that help shape global weather are shifting.  To try to reduce global warming, people want to be able to store even more carbon dioxide in the oceans without the negative effects of doing so.

There are multiple efforts across the globe to achieve effective marine carbon dioxide removal.  Some are based on sinking carbon-rich materials to the bottom of the sea.  This is the marine equivalent of capturing CO2 from the air and storing it underground.  Other efforts involve increasing the alkalinity of the ocean, which increases its ability to chemically react with carbon dioxide as well as lowers its acidity, which is desirable in many ways.

Running Tide, a U.S.-based company, has been dumping thousands of tons of wood-industry waste 190 miles off the coast of Iceland.  The company has also been experimenting with dumping algae and kelp and sinking it deep below the ocean.  Such materials on land either get burned or decay, in both cases releasing CO2 into the atmosphere.  On the deep-sea bottom, the carbon is trapped.

Other efforts involve pumping seawater through electrodialysis filter systems to remove excess acidity or adding alkaline rocks to increase water alkalinity.

All of these efforts are a form of geoengineering, and like proposed ideas to cool the atmosphere, pose potential risks.  There is no silver bullet to solve the climate crisis.  It will take a combination of many solutions to address the issue of excess carbon dioxide in the atmosphere.  Marine carbon dioxide removal is one of the solutions that may play a role.

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Scientists Are Trying to Coax the Ocean to Absorb More CO2

Photo, posted February 22, 2018, courtesy of Bobbie Halchishak/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate change and fish migration

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The warming climate is changing the distribution of fish species.  Researchers at the University of Adelaide in Australia have observed that tropical fish species are moving into temperate Australian waters.

The Eastern Australian Current is strengthening as the climate warms and larvae of tropical fish are getting caught in the current and moving into more temperate regions.  These larvae would not normally survive in the cooler Australian ocean water, but the warming current keeps the baby fish warm and increases their chances for survival.  The fish migration observed in the study is an ongoing process that has strengthened in the last few decades due to ocean warming.

The novel populations of tropical fish in these temperate ecosystems are not having much impact at the present time, but they may do so in the future.  The water is still cooler than the fishes’ natural environment and therefore they do not grow to their maximum size.  As a result, they don’t represent stiff competition for the native species – at least not yet.

As the ocean temperatures continue to rise, these tropical species will eventually grow to their full size and their diets will overlap more and more with those of temperate fish species.  Tropical herbivores tend to overgraze temperate kelp while the impact of tropical fish that eat invertebrates is less well understood.  Tropical fish with varied diets are the most successful invaders.  The ultimate effects on temperate ecosystems remain to be seen but survival may become difficult for the native fish in rapidly warming temperate ocean environments.

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Tropical fish are invading Australian ocean water

Photo, posted March 28, 2017, courtesy of Ryan McMinds via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An active hurricane season

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The Atlantic hurricane season officially runs from June 1st until November 30th.  Forecasters at Colorado State University have issued forecasts of Atlantic basin hurricane activity since 1984 based on the pioneering work of Professor William Gray.  This year’s forecast, issued in April, predicts a higher-than-average number of Atlantic storms.  In fact, it may be one of the most active seasons on record.

On average, there are 14 named storms each season.  This year, the prediction is for 23 of them.  On average, there are 7 hurricanes each season.  This year, the prediction is for 11. The prediction is for 5 major hurricanes among them.  These predictions are among the highest on record, although in 2020 they predicted 12 hurricanes.  In fact, that year there were 14 that actually took place.

Among the factors at play are that the El Niño that was occurring last year has dissipated and there is a good chance of a La Niña forming, which suppresses upper-level winds thereby making conditions ideal for hurricane formation and intensification.  But the overarching factor is global warming which is driving ocean temperature rise.  The water in the Atlantic, especially in the eastern Atlantic where most hurricanes form, has seen record-breaking warmth.  More warm water means more chances for storms.

Other research groups echo the predictions from Colorado State and, in some cases, see ever greater chances for an extremely active hurricane season.  The University of Pennsylvania forecast calls for 33 named storms.

The overall forecast is for a well above-average probability for major hurricanes making landfall along the continental United States coastline and the Caribbean. 

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Weather tracker: US experts predict one of most active hurricane seasons on record

Photo, posted September 5, 2017, courtesy of NASA/NOAA GOES Project 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

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

Mercury in tuna

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Mercury is found throughout the ocean, and there is at least some of it in any fish one might eat. It is an element found naturally in the environment, but it is also a byproduct of manmade pollution. Generally speaking, bigger fish tend to have higher mercury levels than smaller ones, because they are higher up in the food chain. The more small fish those big fish eat, the more mercury builds up in their bodies.  Tuna aren’t the biggest fish in the ocean, but they are very common in many people’s diets.

Increased mercury levels are a result of human activities like burning coal and mining which release methylmercury into the air.  It then finds its way into the oceans in rainwater.  Methylmercury is a particularly toxic chemical that affects the nervous system.  Environmental protection policies in recent decades have helped to reduce mercury pollution.

However, a recent study by French researchers looked at the mercury levels in tuna over the past 50 years.  They found that the levels have basically not changed since 1971.  As a result, they are calling for more restrictive environmental policies to further lower mercury pollution levels.

The researchers explained that the lowering of mercury airborne levels to date has not necessarily been ineffective.  They theorized that the static levels in tuna may be caused by the upward mixing of “legacy” mercury from deeper ocean water into the shallower depths where tropical tuna swim and feed.  It could very well take decades to dramatically reduce ocean mercury levels. 

Meanwhile, mercury content in tuna varies considerably by tuna type and source and there are both better and worse choices out there.  Consumers should learn the facts.

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Mercury levels in tuna remain nearly unchanged since 1971, study says

Photo, posted November 7, 2015, courtesy of Mussi Katz via Flickr.

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