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A starfish to the rescue

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Beginning in 2013, a mysterious disease associated with a marine heatwave decimated the population of sunflower sea stars.  Those huge, colorful 24-armed starfish thrived along the Pacific Coast between Alaska and Baja California.  But in fairly short order, nearly six billion of the creatures perished, amounting to 94% of the global population.  California lost 99% of its sea stars to the wasting disease.

The result was an ecological disaster.  Sunflower sea stars are carnivorous and purple urchins are the mainstay of their diet.  Without sea stars to balance the food web, the urchin population exploded.  Urchins devour kelp and over the past decade, 96% of the region’s kelp forests vanished.  Kelp forests serve as shelter and food for a vast array of marine life and kelp sequesters carbon as much as 20 times more than terrestrial forests.

Researchers in California and Alaska are breeding sunflower sea stars in captivity to try to produce enough of the creatures to support reintroduction.  The first successful spawning of sea stars took place last year at the Birch Aquarium at San Diego’s Scripps Institution of Oceanography.  But all of these are siblings, which is not a desirable breeding stock for a new population.  So, they are now working with the Alaska SeaLife Center, which has the largest collection of the animals in the world.  The center will provide animals to introduce genetic diversity to the growing population in captivity.

The hope is to be able to reintroduce sea stars to the Pacific region within three to five years.

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A rare, giant starfish could hold the key to restoring kelp forests on the California coast

Photo, posted November 11, 2007, courtesy of Patrick Briggs via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tigers in India

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The Anthropocene is the term that describes the current era in Earth’s history when human activities are having a significant impact on the planet.  It is an epoch filled with species extinction and species attrition in both numbers and range.  The population of large carnivores are among the most affected species and recovering these animals that play important roles in ecosystems is a formidable challenge.

Tigers in Asia are a prime example of extirpation – removal of a species from a specific area.  They have been eliminated in more than 90% of their historic Asian range over the past century.  A new study, published in Science has found that tigers in India are making a comeback.

India’s National Tiger Conservation Authority estimates that between 2010 and 2022, India’s tiger population grew from 1,706 to 3,682.  Tigers are thriving not only on protected lands but also near some human communities.

Tigers are gone from poorer areas where poaching was prevalent and from areas affected by the violent conflict associated with India’s Maoist rebellion.  On the other hand, the big cats can be found near some prosperous communities where poaching is rare.  Farmers keep cattle in enclosures to protect them from tigers.  

The success in protecting tigers in India could provide some insights for Europe where wolves are making a comeback, and perhaps even in the American West where the resurgence of wolf populations is triggering a violent backlash.

Large predators can survive in the modern world with creative thinking and willingness to find a balance between protection and coexistence.

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India Doubled its Tiger Population in a Little More Than a Decade

Photo, posted January 8, 2014, courtesy of Roderick Eime via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar forests

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Forests are one of the most iconic symbols of the power and diversity of nature but beyond that, their thick vegetation is crucial to the stability and balance of the Earth’s climate.  This is because the photosynthesis that powers the growth of plants removes carbon dioxide from the air.  Cutting down forests – especially the evergreen forests of the tropics – has played a significant role in the increasing climate crisis.  For this reason, many environmental initiatives focus on restoring destroyed forests and planting new trees.

But the truth is, even if we were to cover the entire surface of the planet with trees, there would still not be enough photosynthesis going on to absorb the huge surplus of carbon dioxide that people have been pumping into the atmosphere for the past 150 years.

A study by the Weizmann Institute of Science in Israel looked at the impact of erecting fields of dark covered solar panels – so-called solar forests – that would generate electricity, thereby replacing power stations that use fossil fuels.  But dark fields absorb heat which eventually returns to the atmosphere.

The question is:  what is the best use of a plot of land in terms of the effect on the climate?  Planting a forest or erecting fields of solar panels?

The answer depends on where the land is.  In arid environments, building solar farms is far more effective and practical than planting forests.  But in humid places, forests currently absorb close to a third of humanity’s annual carbon emissions. 

The study concludes that combining planting and rehabilitating forests in humid regions and erecting fields of solar panels in arid regions is the most effective strategy.

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The Solar Forest

Photo, posted December 27, 2015, courtesy of Gerry Machen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Glacier Loss Day | Earth Wise

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Glaciers are sensitive indicators of climate change that respond to changes in both temperature and precipitation.  But they are not only affected by climate change, they also affect climate change.  As glaciers melt, they contribute to sea level rise, alter regional hydrology, and influence the global energy balance.

A group of glacier experts from the University of Innsbruck in Austria introduced a concept called “Glacier Loss Day” or GLD as a way to measure the annual mass balance of glaciers.  Mass balance is the difference between the amount of snow and ice that accumulates on a glacier and the amount that melts or sublimates.  If the mass balance is positive, the glacier is growing.  If the mass balance is negative, the glacier is shrinking.

GLD is the day during the year when the glacier has lost all the mass it gained during previous winter.  This is a similar concept to Earth Overshoot Day, which marks the date when humankind’s demand for ecological resources exceeds the amount the planet can regenerate during the year.

The Hintereisferner, a glacier in the Tyrolean Alps, has been monitored for more than 100 years and there are continuous records of its mass balance since 1952.  In 2022, the GLD on the Hintereisferner was measured on the 23rd of June.  In the two previous years, it was reached in the middle of August.  Even in years with large negative balances, such as 2003 and 2018, GLD did not occur until the end of July.

Every summer in the future may not be like 2022, but the trend is clear.  Climate change is taking its toll on glaciers.  Experts project that the Hintereisferner will lose half of its volume in the next 10 to 20 years.

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Glacier Loss Day indi­cates record break­ing glacier melt

Photo, posted July 20, 2023, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Too Many Bison | Earth Wise

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In the northern part of Yellowstone National Park, an historically large bison herd is hampering the comeback of quaking aspen trees, whose numbers were greatly diminished by decades of over-browsing by elk.  Restoring the balance of ecosystems at Yellowstone is proving to be a complicated matter.

Long ago, the bison population in the Great Plains was as much as 30 million.  The population sharply decreased in the 1800s.  By the 1830s, there were no bison east of the Mississippi River.  Fifty years later, the Plains bison was nearly extinct.  Several small herds lived near Yellowstone Park when it was established in 1872, but poachers killed off nearly of them by the turn of the century.  Protective measures were taken and by 1925, Yellowstone’s Lamar Valley herd had grown to more than 750.  After that, occasional culling took place for over 40 years. 

When gray wolves and cougars were removed from the park, elk populations boomed, and the elk gradually decimated the growth of quaking aspen, cottonwood, willow, and berry-producing shrubs.  Both elk and bison were regularly culled until 1968 when public and congressional outcry intervened.

The return of wolves and cougars to the park made some progress in restoring ecosystem balance, particularly with respect to the elk population which has dropped from 20,000 to 5,000.  But bison numbers have grown to over 4,000 over past 20 years and the damage once caused by elk is now continuing from bison.

Park administrators are faced with complex management decisions about how to best preserve the ecosystems at Yellowstone National Park.

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Bison in northern Yellowstone proving to be too much of a good thing

Photo, posted October 6, 2016, courtesy of Christian Collins via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate Change On Mount Everest | Earth Wise

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Climate change has shown up in the highest place on Earth.  The highest glacier on Mount Everest is rapidly retreating with rising temperatures.

New research by an international team led by the University of Maine and published in the journal Climate and Atmospheric Science has determined that the South Col Glacier atop Mount Everest has shrunk by half since the 1990s.   Its ice mass has thinned by an estimated 180 feet.

The glacier used to be covered by snow, which reflected the sun’s light and insulated the mass of ice under the snow.  But warmer temperatures, lower humidity, and more severe winds have eliminated the snow cover, fueling the decline of the glacier.

The study of the South Col Glacier highlights the critical balance created by snow-covered surfaces and exposes the potential for loss throughout high mountain glacier systems as snow cover is depleted by warming temperatures.  When even the highest glacier on Mount Everest is impacted, it is clear that no place is safe from the warming climate.

The human significance of this development is substantial.  More than 200 million people in Asia depend on meltwater from glaciers in the high mountains of the continent for their freshwater needs.  But now glaciers in the mountains are melting faster than they can be replenished by snowfall.

As for Mount Everest itself, future expeditions on the mountain will face new challenges as glacier melting causes more avalanches and climbers accustomed to digging into ice and snow will need to scale more exposed bedrock.  Climate predictions for the Himalaya in general all anticipate continued warming and continued loss of glacier mass.

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Climate Change Has Reached the Top of Mount Everest, Thinning Its Highest Glacier

Photo, posted October 27, 2011, courtesy of Goran Hogland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenland Glaciers Past The Point Of No Return | Earth Wise

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Forty years of satellite data from Greenland shows that the glaciers on the island have shrunk so much that even if global warming came to an abrupt halt, the Greenland ice sheet would continue to shrink.

This conclusion was published in the journal Communications Earth and Environment by researchers at Ohio State University.  According to their study, Greenland’s glaciers have passed a tipping point where the snowfall that replenishes the ice sheet each year can no longer keep up with the ice that is flowing into the ocean from the glaciers.

The study analyzed monthly satellite data from more than 200 large glaciers that drain into the ocean around Greenland.  It looked at how much ice breaks off into icebergs or melts from the glaciers into the ocean as well as the amount of snowfall each year that replenishes the glaciers.

Throughout the 1980s and 90s, these two processes were mostly in balance, keeping the ice sheet intact.  But the amount of ice being lost each year started to increase steadily around the year 2000 while there was no increase in snowfall.   Both processes fluctuate from year to year, but the baseline for ice loss has steadily risen.  Before 2000, the Greenland ice sheet had about the same chance of gaining or losing mass each year.  At this point, the ice sheet is likely to gain mass in only one out of every 100 years.

Large glaciers in Greenland have retreated about 2 miles since 1985, so that many of them are sitting in deeper water with more ice in contact with warmer water making it harder for glaciers to grow back.  At this point, even if the climate reverses its trend, the ice sheet will continue to lose mass.

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Warming Greenland ice sheet passes point of no return

Photo, posted August 27, 2015, courtesy of Joxean Koret via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Renewables Without Storage In Texas

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Texas has a Texas-sized appetite for electricity and relies most heavily on natural gas, coal and nuclear power to get it.  But in recent times, wind power has grown tremendously in the Lone Star State and it has already leapfrogged past nuclear power.  Coal could be the next domino to fall.

In the past few years, solar power has become competitive with wind in terms of price.  Texas is a large, coastal state in the sunny southwestern U.S. and has significant solar resources.  As a result, the amount of solar power in Texas is now growing rapidly.

In order for a combination of solar and wind power to address the bulk of electricity demand in Texas, there needs to be a way to provide reliability that these intermittent sources don’t necessarily provide.  Energy storage is a solution that ultimately is likely to be part of most electricity grids, but currently it is still expensive on a utility scale.

A new study from Rice University looked at the complementarity of solar and wind power in Texas.  Complementarity refers to balancing the output of solar and wind systems.  The peak performance of wind and solar occurs at very different times in different regions of the state.  The study suggests that the right mix of solar and wind systems in the right parts of Texas could provide a continuously reliable energy system.  On both a yearly and daily basis, wind and solar power resources in Texas complement each other in terms of peak performance.  It is a matter of locating the solar power and wind farms in the right places.

With the Texas solar industry really starting to boom, there is a real opportunity to integrate far more renewable energy into the Texas grid.

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More Renewables with Less Energy Storage: Texas Shows How

Photo, posted June 8, 2018, courtesy of Laura Lee Dooley 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...)