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Triple La Niña | Earth Wise

January 16, 2023 By EarthWise Leave a Comment

La Niña is an oceanic phenomenon consisting of cooler than normal sea-surface temperatures in the central and eastern tropic Pacific.  It is essentially the opposite of the better-known El Niño.   These sea-surface phenomena affect weather across the globe.  As one oceanographer put it:  when the Pacific speaks, the whole world listens.

There is currently a La Niña underway, and it is the third consecutive northern hemisphere winter that has had one.  This so-called triple-dip event is rather rare.  The only other times they have been recorded over the past 70 years were in 1954-56, 1973-76, and 1998-2001.

La Niñas appear when strong easterly trade winds increase the upwelling of cooler water from the depths of the eastern tropical Pacific Ocean near the equator.  This causes large-scale cooling of the ocean surface.  The cooler ocean surface modifies the moisture content of the atmosphere across the Pacific and can cause shifts in the path of jet streams that intensifies rainfall in some places and causes droughts in others.

These weather effects tend to include floods in northern Australia, Indonesia, and southeast Asia and, in contrast, drought in the American southwest.  In North America, cooler and stormier conditions often occur across the Pacific Northwest while the weather becomes warmer across the southern US and northern Mexico.

In the spring, the tropic Pacific essentially resets itself and starts building toward whatever condition will happen in the following winter, be it another La Niña or possibly an El Niño.   For the time being, forecasters expect the current La Niña to persist through February.

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La Niña Times Three

Photo, posted March 10, 2007, courtesy of Gail via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Antarctic Heatwave | Earth Wise

May 13, 2022 By EarthWise Leave a Comment

The Concordia Research station atop Dome C on the Antarctic Plateau is generally considered to be the coldest place on earth.  In mid-March, the normal high temperature for the day is around -56 degrees Fahrenheit.  But on March 18, the high for the day was 11.3 degrees, nearly 70 degrees warmer than normal.

The World Meteorological Organization doesn’t formally track the metric of largest temperature excess above normal, but if it did, this would probably have set a world record.  Consider a place like Washington, DC.  Its normal high temperature on March 18 is 61 degrees.   Imagine if it got up to 131 degrees! 

The 11-degree reading at the Concordia Research Station was not only the record for the month of March.  It was actually the record for any month.

The Russian Vostok research station, which is another candidate for being the coldest place on earth based on its average high temperature, also saw some record high temperatures.  Vostok reported a high temperature of zero degrees Fahrenheit, which is 63 degrees above its average for the date.  It broke the station’s previous record by almost 27 degrees.

This record warming was the result of a unique combination of meteorological events that included a moist inflow of an atmospheric river as well as a rare infusion of hot air into the Antarctic plateau.  The arrival of the moisture in the atmospheric river trapped the hot air, allowing temperatures to shoot up.

The extreme warmth in Antarctica raises concerns about the long-term effects on the ice there.  A single short heatwave is not going to have a major effect, but if such events become more common, it could be real problem.

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Extraordinary Antarctica heatwave, 70 degrees above normal, would likely set a world record

Photo, posted October 15, 2016, courtesy of NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

River Of Dust | Earth Wise               

April 25, 2022 By EarthWise Leave a Comment

Every year, more than 100 million tons of dust blow out of North Africa.  Strong seasonal winds lift the dust from the Sahara Desert northward.  A few times a year, the winds from the south are strong and persistent enough to drive the dust all the way to Europe.

On March 15, a large plume of Saharan dust blew out of North Africa and crossed the Mediterranean into Western Europe.  European cities were blanketed with the dust, degrading their air quality, and turning skies orange.  Alpine ski slopes were stained with the dust.

These dust events are associated with so-called atmospheric rivers that arise from storms.  Such rivers usually bring extreme moisture but can also carry dust.  Over the past 40 years, nearly 80% of atmospheric rivers over northwestern Africa have led to extreme dust events over Europe.  The March 15 event was associated with Storm Celia, a powerful system that brought strong winds, rain, sleet, hail, and snow to the Canary Islands.

Atmospheric dust plays a major role in climate and biological systems.  The dust absorbs and reflects solar energy and also fertilizes ocean ecosystems with iron and other minerals.

The climate effects of dust are complicated.  Dust can decrease the amount of sunlight reaching the surface, affect cloud formation, and decrease temperatures.  But dust also darkens the snowpack, leading to more rapid snowmelt.  A 2021 dust event resulted in a rapid melt of Alpine snow, reducing its depth by half in less than a month.

The effects of this year’s dust event are not yet known, but this atmospheric river associated with Storm Celia appeared to carry less water and more dust compared with the 2021 event.

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An Atmospheric River of Dust

Photo, posted December 2, 2019, courtesy of Catherine Poh Huay Tan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Importance Of City Trees | Earth Wise

January 28, 2022 By EarthWise Leave a Comment

The importance of street trees in cities

It is well known that green spaces can improve the quality of life and create a better climate in cities.  City trees and vegetation can help reduce urban heat island effects by shading buildings and roads, deflecting radiation from the sun, and releasing moisture into the atmosphere.  City trees and green spaces have also been proven to increase property values, promote wildlife and plant diversity, reduce noise pollution, and improve human health.  But how important are trees and vegetation for producing cleaner air in cities?

According to a new study led by researchers at the University of Gothenburg in Sweden, trees do contribute to cleaner air in cities, but the degree to which they do so varies greatly between different locations. 

The research team measured air pollutants across seven urban settings in the city of Gothenburg, and compared them with pollutants on the leaves of deciduous trees.  The researchers chose to focus on polycyclic aromatic hydrocarbons (PAHs), which are pollutants generated primarily during the incomplete combustion of organic materials, like coal, oil, and wood.

The results revealed that the pollutants in leaves did increase over time.  The researchers were able to show a clear correlation between the level of air pollutants and the concentration of pollutants in leaves. 

But at the same time, the researchers discovered that pollution levels varied greatly between measurement sites.  For example, the levels of PAHs were seven times higher at the most polluted site (the city’s main bus station) than they were at a location on the periphery of the city.

The research team hopes its findings will be used to help guide the planning of future urban landscapes.

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Trees are important for cleaner air in cities

Photo, posted November 5, 2021, courtesy of Maria Eklind via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Seeds And Climate Change | Earth Wise

August 19, 2021 By EarthWise Leave a Comment

Engineering seeds to succeed as the climate changes

Farmers and agricultural communities around the world are on the frontlines of climate change.  They are among the first to feel the impacts of hotter temperatures as well as more frequent and intense droughts and precipitation. These challenges pose a massive threat to both farmer livelihoods and global food security.

As the planet continues to heat up, many arid regions that already have marginal conditions for agriculture will be increasingly under stress. As a result, researchers from the Massachusetts Institute of Technology and the King Mohammed VI Polytechnic University in Morocco are working on a promising new way to protect seeds from this stress during their crucial germination phase. Their simple and inexpensive process, which was recently described in a paper published in the journal Nature Food, also provides plants with extra nutrition at the same.

The research team has developed a two layer coating for seeds designed for tackling issues related to drought. Drawing inspiration from natural coatings that occur on some seeds like chia seeds, the first layer is designed to protect the seeds from drying out. It provides a gel-like coating that grips any moisture that comes along and surrounds the seed with it.  The second (inner) layer of the coating contains preserved microorganisms called rhizobacteria, as well as some nutrients to help the seeds grow. 

The materials for the coatings are biodegradable, readily-available, and often used in the food industry already.  According to researchers, early tests using common beans have demonstrated encouraging results in Morocco, and more field tests of the seeds are currently underway.

As the climate continues to change, more innovations like this will be necessary for global food security.

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Engineering seeds to resist drought

Photo, posted September 17, 2010, courtesy of Stacy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Wood Into Plastic | Earth Wise

May 4, 2021 By EarthWise Leave a Comment

Could wood solve the plastics problem?

Plastic pollution is particularly pernicious because plastics can take hundreds of years to degrade in the environment.  For this reason, researchers across the globe search for ways to shift from petrochemical plastics to ones that are biodegradable.

Producing biodegradable plastics is challenging both from the standpoint of the methods needed and from the results obtained.  Producing them often requires toxic chemicals and can be very expensive.  The materials that emerge often do not have the durability and strength of conventional plastics and can be unstable when exposed to moisture.

Researchers at the Yale School of the Environment have developed a process of decomposing the porous matrix of natural wood into a slurry that can be formed into a biodegradable plastic.  The material shows high mechanical strength, stability when holding liquids, and is resistant to the effects of ultraviolet light.  Along with all these favorable properties, the material can be recycled or safely biodegraded in the natural environment.

The slurry mixture is created by taking wood powder – a processing residue usually discarded in lumber mills – and deconstructing it with a biodegradable and recyclable solvent.  The resulting mixture has a high solid content and high viscosity and can be casted and rolled without breaking.

The researchers conducted a comprehensive life cycle assessment to test the environmental impacts of the bioplastic compared with conventional plastics.  Sheets of it were buried in soil and observed to fracture after two weeks and completely degrade after three months.  The material can also be broken back down into the slurry by mechanical stirring.

The remaining topic to investigate is the potential impact on forests if the manufacturing of this bioplastic is scaled up.

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Turning wood into plastic

Photo, posted October 12, 2016, courtesy of the US Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Your Children’s Yellowstone

January 25, 2019 By EarthWise Leave a Comment

Yellowstone National Park was the first national park in the US and according to some sources, the first in the world.  It is the home of charismatic megafauna and stunning geysers that attract over four million visitors a year.  It is the only place in the United States where bison and wolves can be seen in great numbers.  And it is changing.

Over the next few decades of climate change, Yellowstone will quite likely see increased fire, less forest, expanding grasslands, shallower, warmer waterways, and more invasive plants.  All these things will alter how and how many animals move through the landscape.   Ecosystems are always changing, but climate change is transforming habitats so quickly that many plants and animals may not be able to make the transition at all.

Since 1948, the average annual temperature in the Greater Yellowstone ecosystem has gone up by 2 degrees Fahrenheit.  On balance, winter is 10 days shorter and less cold.  The Northern Rockies snowpack has fallen to its lowest level in eight centuries. Summers in the park are warmer, drier, and increasingly prone to fire.

Non-nutritious invasive plants like cheatgrass and desert madwort have replaced nutritious native plants.  When plants like these take over, they suck moisture out of the ground early so that bison and elk cannot be sustained throughout the summer.

The behavior of elk and other animals is already changing, with many staying outside the park to nibble lawns and alfalfa fields.  In turn, wolves go where the elk go.   Forests and waterways are changing as well.

The rapid changes going on at Yellowstone mean that the park that our children and grandchildren will visit in the future is likely to be a very different one from the Yellowstone we remember.

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In Yellowstone National Park, warming has brought rapid changes.

Photo, posted September 7, 2016, courtesy of Mike Yang via Flickr.  

Earth Wise is a production of WAMC Northeast Public Radio.

Drought In Europe

August 22, 2018 By EarthWise Leave a Comment

https://earthwiseradio.org/wp-content/uploads/2018/08/EW-08-22-18-Drought-in-Europe.mp3

Even as Californians fought giant wildfires and Japan struggled with record high temperatures, the unusual summer heat in central and northern Europe has led to the worst drought conditions in over 40 years.

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Spreading Like Wildfire

October 18, 2017 By EarthWise Leave a Comment

https://earthwiseradio.org/wp-content/uploads/2017/10/EW-10-18-17-Spreading-Like-Wildfire.mp3

Last July 7th, 140 wildfires started up in British Columbia, triggering a state of emergency.  By the end of the summer, more than 1,000 fires had been triggered across the Canadian province, burning nearly 3 million acres of forest, about 10 times more than the average over the past decade.

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Mass Production Of Biodegradable Plastic  

October 17, 2017 By EarthWise 1 Comment

https://earthwiseradio.org/wp-content/uploads/2017/10/EW-10-17-17-Mass-Production-of-Biodegradable-Plastic.mp3

Plastic pollution is a major problem for the world’s oceans and non-biodegradable plastics continue to fill the planet’s landfills and litter the landscape.   There are many approaches to making plant-derived, biodegradable plastics but most of these materials do not offer the resistance to heat and moisture that is characteristic of petroleum-based plastics.

[Read more…] about Mass Production Of Biodegradable Plastic  

Tipping Points

August 9, 2017 By EarthWise

https://earthwiseradio.org/wp-content/uploads/2017/08/EW-08-09-17-Tipping-Points.mp3

A tipping point is a point in time when a small thing can make a big change happen.  The term was popularized in sociology in recent decades, but really comes from physics where is refers to adding a small amount of weight to a balanced object causing it to topple over.

[Read more…] about Tipping Points

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