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Extending the shelf life of produce

July 10, 2025 By EarthWise Leave a Comment

More than 30% of the world’s food is lost after it has been harvested. That’s enough to feed more than a billion people. Much of that loss is fruits and vegetables that go bad before they can be eaten.

Refrigeration is the most common way to preserve foods, but the energy and infrastructure required is not always available, especially in less affluent regions of the world.

Researchers at MIT and Singapore-based collaborators have demonstrated that they can extend the shelf life of harvested plants by injecting them with melatonin using biodegradable microneedles.

Silk microneedles are tiny, nontoxic, and biodegradable and represent a means of delivering nutrients to plants without triggering a stress response.

Melatonin is a natural hormone that plants already use. Injecting it was shown to extend vegetables’ shelf life. The tests used pak choy, an important Asian crop that is very perishable. Untreated plants at room temperature yellowed within two or three days. In contrast, treated plants stayed green for five days. Overall, treated plants retained saleable value for 8 days. Refrigerated plants had their shelf life extended considerably as well. However, the most significant value of the technique is that it could enhance the shelf life of perishable produce like pak choy without needing access to refrigeration.

The dose of melatonin delivered to the plants is so low that it is fully metabolized by the crops, so it would not significantly increase the amount normally present in the food. People would not ingest more melatonin than usual. The researchers believe that their technique should work with all kinds of produce.

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A new technology for extending the shelf life of produce

Photo, posted May 6, 2010, courtesy of Jessica Spengler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Species and climate change

July 4, 2024 By EarthWise Leave a Comment

Temperature extremes on Earth currently range from a low of -129°F to a high of 134°F. But these climatic limits have changed throughout history. In fact, during the last interglacial period 130,000 years ago, temperatures were warmer, resembling what we are projected to experience at the end of this century.

Species that evolved during such periods may possess pre-adaptations that could help them tolerate upcoming changes to the climate. This factor is often overlooked by traditional statistical models predicting species’ responses to climate change.

But a new model, developed by researchers from Ifremer in France and Lausanne University in Switzerland, has taken this oversight into account, and reassessed the proportion of terrestrial and marine species threatened with extinction by climate change.

In the study, which was recently published in the journal Nature Ecology and Evolution, the research team applied its model to nearly 25,000 terrestrial and marine species from around the world. The researchers discovered that 49% of these species live in climate niches near the current climatic limits, and 86% could potentially extend beyond these limits.

The most surprising result concerns tropical regions. While forecasts from traditional models estimate that the diversity of terrestrial species in tropical areas could decrease by 54% between now and 2041-2060, the new model predicts a more moderate decline of 39%.

The findings confirm the importance of taking urgent measures to mitigate climate change and its impact on biodiversity.

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Some species may better tolerate climate change than expected

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

Earth Wise is a production of WAMC Northeast Public Radio

Skiing and climate change

April 12, 2024 By EarthWise Leave a Comment

According to the National Oceanic and Atmospheric Administration, anthropogenic climate change resulting in higher average temperatures has caused a global decline in snowfall. Less snow threatens to reinforce global warming, and to disrupt food, water, and livelihoods for billions of people.

According to a new study recently published in the journal PLOS ONE, annual snow cover days in all major skiing regions are projected to decrease dramatically as a result of climate change. In the study, the research team from the University of Bayreuth in Germany examined the impact of climate change on annual natural snow cover in seven major skiing regions. Using the public climate database CHELSA, the researchers predicted annual snow cover days for each ski area for 2011-2040, 2041-2070, and 2071-2100 under low, high, and very high carbon emissions scenarios.

Under the high emissions scenario, 13% of ski areas are predicted to lose all natural snow cover by 2071-2100 relative to their historic baselines. By 2071-2100, average annual snow cover days were predicted to decline by 78% in the Australian Alps, 51% in the Southern Alps, 50% in the Japanese Alps, 43% in the Andes, 42% in the European Alps, 37% in the Appalachians, and 23% in the the Rocky Mountains – all declines relative to their historic baselines.

The future losses of natural snow cover in ski areas around the world will be significant if global emissions continue unchecked.

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The future is likely less skiable, thanks to climate change

New maps show where snowfall is disappearing

Photo, posted April 14, 2006, courtesy of Kallu via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record low Antarctic sea ice

October 30, 2023 By EarthWise Leave a Comment

Antarctica’s winter came to a close in September and during that month, the continent reaches its maximum amount of sea ice that grows during the darkest and coldest months. This year, that maximum occurred on September 10th and turned out to be the lowest on record.

The sea ice around Antarctica reached a maximum extent of 6.5 million square miles according to NASA researchers. That was nearly 400,000 square miles below the previous record low set in 1986.

There are several possible causes for the meager growth of Antarctic sea ice this year. It may be a combination of several factors including El Niño, wind patterns, and warming ocean temperatures. Recent research indicates that ocean heat is most likely playing an important role in slowing ice growth in the cold season and enhancing ice melting in the warm season.

The record-low ice extent so far this year is a continuation of a downward trend in Antarctic sea ice that has gone on since the ice reached a record high in 2014. Prior to that year, the ice surrounding the southern continent was actually increasing slightly by about 1% every decade.

Meanwhile, Arctic sea ice reached its minimum extent in September and it was the sixth-lowest level in the satellite record. Scientists track the seasonal and annual fluctuations of polar sea ice because they shape polar ecosystems and play a significant role in global climate. Sea ice melting at both poles reinforces global warming because bright sea ice reflects most of the Sun’s energy back to space while open ocean water absorbs 90% of it.

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Antarctic Sea Ice Sees Record Low Growth

Photo, posted June 30, 2023, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Groundwater Crisis | Earth Wise

September 22, 2023 By EarthWise Leave a Comment

The majority of U.S. drinking water systems rely on groundwater, as do America’s farms. Even though groundwater is a crucial resource for the country, there is no central oversight or even monitoring of its status across the country. The health of the country’s aquifers is difficult to gauge.

The New York Times spent months amassing data from 80,000 wells across the country by reaching out to federal, state, and local agencies nationwide.

The survey found that 45% of the wells examined showed a statistically significant decline in water levels since 1980. Forty percent of the sites reached record-low water levels over the past 10 years, with last year the worst yet.

Over pumping is the biggest problem. State regulations tend to be weak and there is no federal oversight. The warming climate reduces snowpack, which means less water in rivers, increasing the need to tap into groundwater. Warmer weather means thirstier plants, increasing the demand for water.

It is a nationwide problem, not just one in the drought-ridden West. Arkansas, which produces half of the country’s rice, is pumping groundwater twice as fast as nature can replace it. Three-quarters of Maryland’s wells have seen substantial drops in water levels.

As groundwater is pumped out, the empty space can collapse under the weight of the rock and soil above it, permanently diminishing the capacity for future groundwater storage.

There are likely to be parts of the U.S. that run out of drinking water and groundwater depletion threatens America’s status as an agricultural superpower. Objectively, the status of American groundwater is a crisis that threatens the long-term survival of communities and industries that depend on it.

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Five Takeaways From Our Investigation Into America’s Groundwater Crisis

Photo, posted July 25, 2009, courtesy of Chris Happel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Low Antarctic Sea Ice | Earth Wise

March 2, 2023 By EarthWise Leave a Comment

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

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

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

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

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Record low sea ice cover in the Antarctic

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

Earth Wise is a production of WAMC Northeast Public Radio

Carbon Inequality | Earth Wise

November 4, 2022 By EarthWise Leave a Comment

Everyone contributes to climate change through the generation of greenhouse gas emissions, but individual contributions vary greatly. A study at the Paris School of Economics has determined that just 1 percent of the population is responsible for nearly a quarter of global carbon emissions growth since 1990.

The study estimated emissions from individuals’ consumption and their financial investments, and also from government spending in their country. Individuals are responsible for carbon emissions as a result of their own activities, but they also bear their share of responsibility for the emissions of the firms that they own or invest in.

In 2019, people living in sub-Saharan Africa produced an average of 1.8 tons of CO₂ equivalent per capita. In North America, the average per capita was more than 10 times higher. Meanwhile, the top 10% of North America’s emitters produced more than 75 tons each.

From 1990 to 2019, the bottom 50% of emitters was responsible for just 16% of emissions growth, while the top 1% was responsible for 23%. The top 0.1% saw emissions growth of 80%.

The inequality between rich and poor is driven more by inequality within countries than by inequality between countries. This is particularly true for wealthy countries. For example, over the study period, the top 1% saw their emissions grow by 26% while emissions actually declined 5-15% among low and middle earners even in wealthy nations.

Economic inequality drives a lot of the dynamics taking place within many countries around the world, and this even applies to pollution and greenhouse gas emissions.

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Global carbon inequality over 1990–2019

Photo, posted December 11, 2017, courtesy of Bernal Saborio via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Trouble For The Outer Banks | Earth Wise

August 9, 2022 By EarthWise Leave a Comment

The Outer Banks are a series of barrier islands off the coast of North Carolina that separate the Atlantic Ocean from the mainland. They are a very popular tourist destination featuring open-sea beaches, state parks, shipwreck diving sites, and historic locations such as Roanoke Island, the site of England’s first settlement in the New World. There is also Kitty Hawk, the site of the Wright Brothers’ first flights.

The ribbon of islands is nearly 200 miles long. Some of them are low and narrow and are only a few feet above sea level. Many are especially vulnerable to Nor’easters in the winter and hurricanes in the summer. The collision of warm Gulf Stream waters and the colder Labrador current helps to create dangerous shoals and some of the largest waves on the East Coast.

Over the years, developers have added billions of dollars’ worth of real estate to the Outer Banks. Rising sea levels and increasingly frequent storms threaten the barrier islands of the Outer Banks. Beach-front cottages have tumbled into the ocean for as long as people have built them in the Outer Banks but now they are falling at a greater rate and more and more are in danger.

The Department of Transportation has spent nearly $100 million dollars to keep NC12, the highway connecting the string of islands, open to traffic. Three new bridges built to traverse inlets opened by storms and bypassing rapidly eroding shorelines raised the cost by another half a billion dollars.

There are many other measures such as pumping sand into eroded areas going on in the Outer Banks, but ultimately, all of the measures may not be enough to deal with rising sea levels and more powerful storms.

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