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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

Rising methane emissions

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Methane is a colorless and odorless gas that occurs abundantly in nature and is also a product of certain human activities.  It’s a short-lived but highly potent greenhouse gas and, as a result, is a major driver of climate change.  In fact, methane heats the atmosphere nearly 90 times faster than carbon dioxide over a 20-year period. 

Despite a global pledge from more than 150 nations to reduce methane emissions by 30% this decade, methane emissions continue to rise.  In fact, according to a new paper led by researchers from Stanford University, total annual methane emissions have increased 20% over the past two decades. 

The paper, which was recently published in the journal Environmental Research Letters, found that atmospheric concentrations of methane today are more than 2.6 times higher than in pre-industrial times.  In fact, atmospheric methane concentrations are currently the highest they’ve been in at least 800,000 years.

Methane emissions from coal mining, oil and gas production and use, cattle and sheep ranching, and decomposing organic waste in landfills are responsible for driving the growth.  In 2020, the most recent year for which data was available, nearly 400 million tons – or about two-thirds – of global methane emissions came directly from human activities. 

Methane concentrations in Earth’s atmosphere have increased at record speed over the past five years.  According to the research team, only the European Union and possibly Australia seem to have decreased methane emissions from human activities over the past two decades.  This trend “cannot continue if we are to maintain a habitable climate.”

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Methane emissions are rising faster than ever

Photo, posted December 4, 2010, courtesy of Dani Mettler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Slow-moving landslides

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Landslides are mass movements of rock, earth, or debris down a slope.  They can be initiated by rainfall, snowmelt, changes in water level, erosion by streams, earthquakes, volcanic activity, or by various human activities.  Most landslides we hear about are sudden events that can cause all sorts of calamities.  But not all landslides are rapid occurrences.  There are also slow-moving landslides.

A new study by the University of Potsdam in Germany has found that as urban centers in mountainous regions grow, more people are building homes on steeper slopes prone to slow-moving landslides.  Slow-moving landslides can move as little as one millimeter a year and up to as much as three meters per year.  Locations with slow-moving landslides can seem safe to settle on; in some cases, the movement itself can be inconspicuous or even completely undetected.

Slow slides can gradually produce damage in houses and other infrastructure and there can also be sudden acceleration from heavy rain or other influences.

The study compiled a new database of nearly 8,000 slow-moving landslides with areas of at least 25 acres located in regions classified as “mountain risk.”  Of the landslides documented, 563 are inhabited by hundreds of thousands of people.  The densest settlements on slow-moving landslides are in northwestern South America and southeastern Africa. 

In all regions of the study, urban center expansion was associated with an increase in exposure to slow-moving landslides.  As cities expand in mountainous areas, people are moving into unsafe areas, but poorer populations may have few other options.

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Slow-moving landslides a growing, but ignored, threat to mountain communities

Photo, posted March 4, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Just say ‘climate change’

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In recent years, climate advocates have pushed for the use of more dramatic language to describe ‘climate change.’  The notion was that phrases like ‘climate crisis’ and ‘climate emergency’ better convey the urgency of the planet’s plight, while terms like ‘climate change’ and ‘global warming’ are too gentle and vague.  However, it turns out that the gentler approach may actually be more effective.

According to a new study led by researchers from the University of Southern California, the terms ‘climate change’ and ‘global warming’ are not only more familiar to people than some of their common synonyms, but they also generate more concern about the warming of the Earth.

In the study, which was recently published in the journal Climatic Change, the research team found that nearly 90% of respondents were familiar with the terms ‘climate change’ and ‘global warming.’  However, familiarity dropped sharply for the other terms, including ‘climate crisis’ and ‘climate emergency.’  In fact, only 33% of respondents recognized the term ‘climate justice.’

The study, which surveyed more than 5,000 randomly selected U.S. residents, examined the degree to which each term generated concern, urgency, willingness to support climate-friendly policies, and willingness to eat less red meat. 

The research team found that the terms ‘climate change’ and ‘global warming’ were most concerning and most urgent.  ‘Climate justice’ was the least, with ‘climate crisis’ and ‘climate emergency’ falling in between.  The support for climate policy and willingness to eat less red meat was roughly the same, regardless of what terms were used. 

The research team hopes its findings will help us communicate more effectively about climate change in the future.

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Just Say “Climate Change” – not “Climate Emergency”

Photo, posted July 1, 2023, courtesy of Sheila Sund 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

The hottest day on record

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There have been numerous temperature records set in recent years.  Apart from record high temperatures for many places around the world, there were 13 consecutive monthly temperature records set for the planet since the previous summer.

According to NASA data, July 22, 2024, was the hottest day on record.  July 21st and 23rd also exceeded the previous daily record, which was set in July last year.  The new record was 17.16 degrees Celsius, or about 63 degrees Fahrenheit.

We are not used to thinking in terms of the global average temperature.  That is the number that keeps climbing and that climate goals seek to keep from getting too high.  The global average temperature is about 59 degrees Fahrenheit.  So, on July 22nd, the Earth was about 4 degrees warmer than usual.  That may not seem like much, but it takes an enormous amount of energy to raise the temperature of the planet by that amount.

The NASA report shows the global daily temperature throughout the year for the years 1980 to 2024.  It clearly shows how much warmer temperatures are now compared with the previous decades.

In many places, people experienced persistent hot weather during the month of July. New York’s Capital Region saw relentless hot and humid weather.  There were 9 days with high temperatures in the 90s.   July in Albany had a monthly mean temperature of 77.3 degrees, which was the highest in any current resident’s lifetime.  This is more than 4 degrees higher than the average over the past 30 years.  The last time the average temperature was over 77 was in 1887.  July was hot.

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NASA Data Shows July 22 Was Earth’s Hottest Day on Record

Photo, posted October 22, 2016, courtesy of Susanne Nilsson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Averting a mass extinction

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There has been widespread concern that biodiversity is under siege and that we are in the beginnings of a sixth mass extinction in the long history of the Earth, this time caused by the actions of humanity.  There has been considerable debate about what can be done about it and solutions generally involve protecting large areas of the planet from human disruptions.  Some countries have set a target of protecting 30% of land and sea.

A new study by a broad coalition of conservation organizations and published in Frontiers in Science, concludes that humans can preserve much of the great diversity of life on Earth by setting aside just 1.2% of the planet for protection.

The experts mapped the wilderness available to rare and threatened plants and animals.  They then identified specific hotspots for rare wildlife that have yet to be protected.  They found a total of 16,825 such sites which nevertheless all together add up an area smaller than the state of Wisconsin.

Some scientists have been warning that by focusing too much on the size of protected lands, we are not necessarily safeguarding areas that are especially rich in wildlife.  The new study pushes for prioritizing hotspots for rare species, which the authors claim would be sufficient to stave off a sixth mass extinction.  The truth is that most species on Earth are rare, meaning that they are few in number or cover a small range, or both.

The study estimated that the cost of protecting the identified hotspot sites would be $263 billion, which is certainly a large amount of money.  But the authors point out that this sum to save global biodiversity is less than the yearly revenue of Shell Oil.

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To Avert a Mass Extinction, Protect 1 Percent of Earth

Photo, posted April 20, 2018, courtesy of Per Harald Olsen / AfricanBioServices via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Species and climate change

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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

Cloud brightening

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Solar geoengineering is a type of climate intervention:  deliberate actions designed to affect the climate.  There are several ways to try to reduce the amount of sunlight reaching the surface of the earth and all of them are controversial.  Perhaps the least controversial approach is cloud brightening.

The idea is based on something called the Twomey effect, which is that large numbers of small droplets in the atmosphere reflect more sunlight than small numbers of large droplets.  Spraying vast quantities of minuscule aerosols into the sky, thereby forming many small droplets, could change the reflective properties of clouds.  If clouds are more reflective, then less sunlight reaches the surface, and the temperature goes down.

This form of geoengineering is thought to be less risky because it can be performed on a localized basis and can use relatively benign materials such as sea salt. 

In early April, scientists from the University of Washington started testing a device that sprays tiny sea-salt particles into the air from the deck of a decommissioned aircraft carrier in Alameda, California.  The test was simply to see whether the machine propelled a mist of suitable size.

Within two weeks, Alameda officials ordered a stop to the experiment, citing potential health and environmental risks.  After a month-long investigation, Alameda ruled that the experiment does not generate a measurable risk to health, wildlife, or the environment.

But before more ambitious experiments take place, there are potential side effects of cloud brightening that need to be studied.  It may turn out to be a useful tool in fighting global warming, but in any case, such technology should not be viewed as a substitute for moving away from fossil fuels.

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A Test of Cloud-Brightening Machines Poses No Health Risk, Officials Say

Photo, posted September 8, 2011, courtesy of Justin Ladia via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon dioxide and wildfires

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Climate change is a key factor in the increasing risk and extent of wildfires.  Wildfires require the alignment of several factors, including humidity, temperature, and the lack of moisture in fuels, such as trees, shrubs, and grasses.  All of these factors have strong ties to climate variability and climate change.

While the global surge in wildfires is often attributed to hotter and drier conditions, a new study by researchers from the University of California – Riverside has found that increasing levels of a greenhouse gas may be an even bigger factor. 

According to the study, which was recently published in the journal Communications Earth & Environment, carbon dioxide is driving an increase in the severity and frequency of wildfires by fueling the growth of plants that become kindling.

Centuries of burning fossil fuels to produce heat, electricity and to power engines has added alarming amounts of carbon dioxide to the atmosphere.  In fact, atmospheric CO2 levels are measuring more than 420 parts per million, which is a level not seen on earth for 14-16 million years. 

Plants require carbon dioxide, along with sunlight and water, for photosynthesis.  But rising levels of CO2 in the atmosphere are driving an increase in plant photosynthesis – an effect known as the carbon fertilization effect.  This effect can make plants grow bigger and faster. 

Warming and drying are important fire factors.  These are the conditions that make the extra plant mass more flammable.  But the study found that the increase in fires during hotter seasons is driven by the CO2-fueled growth of plants.   

The researchers hope their findings will urge policymakers to focus on reducing carbon dioxide levels in the atmosphere.

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CO2 worsens wildfires by helping plants grow

Current carbon dioxide levels last seen 14 million years ago

Photo, posted January 17, 2024, courtesy of Jennifer Myslivy, BLM Fire/NIFC via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Where not to plant trees

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Planting huge numbers of trees is often proposed as a way to reduce the severity of climate change.  Studies have looked at the potential for Earth‘s ecosystems to support large additional areas of forest and have found that it would be possible to have at least 25% more forested area than we do now.  This in turn could capture large amounts of carbon and substantially reduce the amount in the atmosphere.

A recent study by researchers at Clark University in Massachusetts and The Nature Conservancy mapped the climate impact of tree planting across the globe, identifying where it would be most and also least beneficial.  The study, published in Nature Communications, found that trees planted in arid, desert regions or in snowy places like the Arctic would, on balance, worsen warming rather than reduce it.

Trees take up carbon dioxide from the atmosphere, which helps to keep warming in check.  But trees with dark, green leaves also absorb heat from sunlight.   Snow and desert sand, on the other hand, are light-colored and reflect more sunlight back into space.  For this reason, trees planted in snowy areas or in the desert will absorb more sunlight than their surroundings.  This can negate the climate benefits of soaking up carbon dioxide.

Previous studies only looked at how much carbon dioxide would be removed by planting trees in order to determine how much warming would be prevented.  The new study finds that it matters where the trees are planted.

Fortunately, the new study also shows that tree planting projects that are currently underway or that are in the pipeline are largely concentrated in regions where they will indeed help slow global warming.

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This Map Shows Where Planting Trees Would Make Climate Change Worse

Photo, posted April 5, 2022, courtesy of UC Davis Arboretum and Public Garden 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

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

Natural hydrogen

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Hydrogen is considered to be a potential substitute for conventional fossil fuels in applications where electricity cannot easily be used such as in blast furnaces, cement works, industrial heating, long-distance aviation, and shipping.  But most hydrogen is manufactured by separating it from methane, which is energy-intensive and produces carbon dioxide.  So-called green hydrogen is made by splitting water using electricity.  It is a carbon-free process if the electricity is from renewable sources, but it is pretty expensive.

A small community in Mali gets its electricity by burning natural hydrogen, which bubbles up from underground into a village well.  It has long been known that processes in the Earth’s crust can make hydrogen gas from water under certain circumstances.  But conventional wisdom has been that this occurrence is rare and that the hydrogen produced is either inaccessible or seeps away.

An increasing number of geoscientists now are convinced that there is actually an enormous quantity of hydrogen beneath the planet’s surface and that we just haven’t been looking for it in the right places, or at all, for that matter.  Some say that there could be trillions of tons of hydrogen, and more is being generated all the time.

Prospectors have recently been drilling for hydrogen in France, Australia, Morocco, Brazil, and in the United States, in Nebraska, Arizona, and Kansas.  Will extracting natural hydrogen be practical at the scale required and will it be economical?  The jury is still out on all of this, but if it turns out as proponents claim, natural hydrogen could be a very big deal.

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Natural Hydrogen: A Potential Clean Energy Source Beneath Our Feet

Photo, posted November 4, 2012, courtesy of Heather Paul via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Elephants and protected areas

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Standing up to 13 feet tall and weighing up to 7 tons, African savanna elephants are the largest species of elephant and the biggest terrestrial animal on Earth.  According to the World Wildlife Fund, African savanna elephants can be found in 23 countries and live in a variety of habitats, including savannas, forests, and deserts.  The largest populations are in Southern and Eastern African countries.

According to assessments from the International Union for Conservation of Nature, the population of African savanna elephants has decreased by at least 60% over the last 50 years.  Poaching and habitat loss are the two main drivers of the population decline.  In 2021, the status of the African savanna elephant was changed from vulnerable to endangered on the IUCN’s Red List of Threatened Species. 

However, according to a new study recently published in the journal Science Advances, conservation measures have successfully stopped African savanna elephant population declines across southern Africa.  The international team of researchers found that the pattern varies regionally, with some elephant populations soaring while others are still facing large declines.

Overall, the study found that there are the same number of elephants now as there were 25 years ago. According to researchers, the key to long-term elephant population growth and sustainability isn’t where a protected area is, but rather how connected it is to other protected or neutral areas around it. 

This isn’t a new concept; in fact, many parks have been connected to one another.  But this study helps prove that the method is effective for elephant conservation.  

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Protected Areas for Elephants Work Best if They Are Connected

African elephant species now Endangered and Critically Endangered – IUCN Red List

African savanna elephant

Photo, posted October 20, 2018, courtesy of Ray via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

More mosquitoes in a warming climate

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Over millions of years, Earth’s climate has warmed up and cooled down many times. However, today the planet is warming much faster than it ever has over human history.  According to scientists, the warming is primarily the result of increased anthropogenic greenhouse gas emissions.  In fact, human activities are responsible for nearly all of the increase in atmospheric greenhouse gas emissions over the last 150 years. 

According to a new study published in the journal Ecology, the warming climate may soon mean more mosquitoes.  A research team, led by scientists from Virginia Commonwealth University, found that rising temperatures, often linked to climate change, can make predators of mosquito larvae less effective at controlling mosquito populations.  According to researchers, these warmer temperatures accelerate the development time of larvae, which leads to a smaller window of time in which predators like dragonflies could eat them.  As a result, twice as many mosquito larvae could make it to adulthood in the study area. 

Predators help stabilize ecosystems and food webs.  The study looked at predator-prey interactions between dragonfly nymphs and mosquito larvae.  In the study of Belle Isle along the James River in Richmond, Virginia, the research team found that warmer pools had more aquatic rock pool mosquito larvae – even when their predators that naturally control the populations were present.

While this species of mosquito is not an important disease vector, the researchers emphasize that these findings likely apply to other mosquito species that do act as vectors for diseases, such as West Nile or Zika virus.

The changing climate is creating the perfect environment for mosquitoes to thrive. 

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Hotter weather caused by climate change could mean more mosquitos, according to VCU-led study

Photo, posted June 20, 2014, courtesy of John Tann 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

Solar thermochemical hydrogen

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For decades, there has been talk of the hydrogen economy in which hydrogen would take the place of fossil fuels in a wide range of domestic and industrial applications.  Over time, hydrogen’s potential advantages in some applications have diminished but it is still seen as perhaps the most promising way to decarbonize long-distance truck, ship, and plane transportation as well as many heavy-duty industrial processes.

Hydrogen is the most common element in the universe, but here on Earth, it is tightly bound up in chemical compounds, notably water and hydrocarbons.  Extracting hydrogen from these compounds takes lots of energy.  To date, most hydrogen is produced from fossil fuel sources, resulting in carbon dioxide emissions.  So-called green hydrogen is made by splitting up water into its component elements.

Getting hydrogen from water generally uses electrolysis, which requires lots of electrical power.  That is why it isn’t the standard way to produce hydrogen; it costs too much to pay for all that power.

MIT scientists have been developing a process to make solar thermochemical hydrogen, or STCH.  STCH uses the sun’s heat to split apart water and no other energy source.  An existing source of solar heat drives a thermochemical reaction in which a heated metal surface grabs oxygen from steam and leaves hydrogen behind.  MIT did not invent the concept; their efforts are to make it practical.

Previous STCH designs were only capable of using 7% of incoming solar heat to make hydrogen.  The MIT process may be able to harness up to 40% of the sun’s heat and therefore generate far more hydrogen. 

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MIT design would harness 40 percent of the sun’s heat to produce clean hydrogen fuel

Photo, posted August 23, 2017, courtesy of Evan Lovely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geoengineering could create winners and losers

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Geoengineering – deliberate interventions to alter the climate and curb climate change – is a controversial topic, to say the least.  Once practically considered taboo even to discuss, there in increasing interest in at least exploring various ideas about how to halt or reverse climate change through direct actions that impact global temperatures.

Putting aside the very real concerns about the risks and dangers associated with such action, there is also the issue that climate interventions may create dramatically different effects across the globe, benefitting some areas and adversely affecting others.

A recent study by scientists at Rutgers University tackled this very issue.  Published in the journal Nature Food, it described the results of computer models simulating the impacts of stratospheric aerosol intervention (SAI), which is spraying sulfur dioxide into the stratosphere, where it would partially shield the Earth from the Sun, lowering temperatures.

The study looked at 11 different SAI scenarios and found that none of them benefitted everyone.  Uncontrolled global warming favors crop production in cold, high-latitude areas such as Canada, Russia, Scandinavia, and our northern border states.  Moderate amounts of SAI favors food production in the mid-latitudes (such as in the US and Europe.)  Large amounts of intervention favors agricultural production in the tropics. 

Even if geoengineering might not have dire consequences – which is by no means certain – it would create winners and losers.  Nations may have different ideas of what constitutes an optimal global temperature.  So, who gets to decide where to set the global thermostat?  The prospects for conflict loom large. 

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Climate Intervention Technologies May Create Winners and Losers in World Food Supply

Photo, posted November 18, 2021, courtesy of Conall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastics In The Air | Earth Wise

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Plastic pollution is a big deal.  There are plastics clogging up landfills and waterways and accumulating in the oceans, choking turtles and seabirds.  Annual production of plastics has grown from 2 million tons a year in 1950 to more than 450 million tons today.

As if plastic problems weren’t already big enough, it is becoming increasingly clear that there are growing amounts of microplastic particles in the air. Bits of plastic are lofted into the sky from seafoam bubbles and from spinning tires on highways.  The particles are so light that they can travel for thousands of miles, far from where they originate.

Studies in recent years documented the presence of plastic particles even in places like the Pyrenees in Europe and in federally protected areas of the US.  Other studies have measured the quantity of plastic in the air of various locations and have looked at the origins of the particles.

In the western US, over 80% of microplastics came from roads where vehicles kick up particles from tires and brakes.   In remote areas of the Pacific, there is less than a single particle of plastic per cubic meter of air.  In cities like London and Beijing, on the other hand, there can be several thousand particles per cubic meter.

Microplastics can act as airborne aerosols, like dust, salt, soot, volcanic ash, and other particles.  Aerosols play an important role in the formation of clouds and in temperature regulation on the earth.  At low concentrations, such as exist in most places, microplastic aerosols don’t have much of an effect.  But there are more in the atmosphere all the time and, at this point, scientists don’t really know what effect they will have.

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Microplastics Are Filling the Skies. Will They Affect the Climate?

Photo, posted August 28, 2014, courtesy of Alan Levine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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