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The bloated carbon footprint of LNG

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According to the U.S. Department of Energy, the United States is the world’s largest producer of natural gas.  In fact, natural gas supplies approximately one third of the United States’ primary energy consumption, most of which is used to heat buildings and to generate electricity.  While most natural gas is delivered in its gaseous form in this country, the demand for natural gas in international markets has given rise to the use of natural gas in a liquified form. 

Liquified natural gas (LNG) is natural gas that has been cooled to a liquid state, at about -260° Fahrenheit, for easier storage and transportation.  The volume of natural gas in its liquid state is about 600 times smaller than its volume in its gaseous state, which makes it possible to transport it to places pipelines do not reach.

Liquified natural gas is considered a clean fossil fuel because burning it produces less emissions than coal and oil.  However, according to a new study by researchers from Cornell University, LNG imported from the U.S. actually has a larger climate impact than any other fossil fuel—including coal – once processing and shipping are taken into account. 

The study, which was recently published in the journal Energy Science & Engineering, found that LNG leaves a greenhouse gas footprint that is 33% worse than coal when emissions are analyzed over a 20-year time frame. 

According to the research team, there is no need for LNG as an interim energy source because the transition requires massive infrastructure expenditures.  Instead, those financial resources should be used to “build a fossil-fuel-free future as rapidly as possible.”

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Liquefied natural gas carbon footprint is worse than coal

Photo, posted November 17, 2017, courtesy of Colin Baird via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing emissions from cement

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Cement production accounts for about 7% of global carbon emissions.  It is one of the most difficult challenges for emissions reduction.  The emissions associated with producing cement come from both the energy used to provide heat for the process and from the chemical reactions that take place in the formation of cement.  Cement is an essential building block of society, and its use is not expected to decline over time.

A German company called Heidelberg Materials is embarking on an ambitious project to reduce carbon emissions from a cement plant in Norway.  They are building a facility to use absorbent chemicals to capture large quantities of carbon dioxide emitted through cement production.  More than half a ton of carbon dioxide arises from every ton of cement produced at the plant.

Once the carbon dioxide is captured it will be chilled to a liquid, loaded onto ships, and carried to a terminal farther up the Norwegian coast.  From there, it will be pumped into undersea rocks located 70 miles offshore and a mile and a half below the bottom of the North Sea.

With all of this complicated process going on, cement from the plant is likely to be quite expensive.  It might even be two or three times the price of ordinary cement.  Heidelberg Materials is counting on customers’ willingness to pay much more for cement that comes with green credentials. 

Can this be economically viable?  Heidelberg estimates that cement accounts for only about 2% of the cost of a large building project but as much as 50% of the emissions.  As a result, using carbon-free cement could be a relatively inexpensive way for builders to reduce emissions.

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Cement Is a Big Polluter. A Plant in Norway Hopes to Clean It Up.

Photo, posted May 7, 2016, courtesy of Phillip Pessar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Shrinking polar ice

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Arctic sea ice has shrunk to near-historic lows during this Northern Hemisphere summer.  The minimum extent for the year occurred on September 11th.  Ice cover in the Arctic Ocean has been shrinking and thinning for more than 40 years.  The amount of frozen seawater in the Arctic goes up and down during the year as sea ice thaws and regrows between seasons.

This year, the minimal extent of sea ice shrank to 1.65 million square miles.  That’s about 750,000 square miles less than the average for late summer over the years between 1981 and 2010, representing a decrease of more than 30%.  The all-time low of 1.31 million square miles was actually set in 2012.  Sea ice coverage can fluctuate from year to year, but it has trended downward since it has started being tracked in the late 1970s.  The loss of sea ice has averaged about 30,000 square miles per year.

Sea ice extent has not only been shrinking; the ice has been getting younger and thinner.  Presently, the overwhelming majority of ice in the Arctic Ocean is first-year ice, which is thinner and less able to survive the warmer months.  There is far less ice that is three years or older.

Meanwhile, sea ice in the southern polar regions was also low this year.  In the sea around Antarctica, scientists are tracking near record-low sea ice at a time when it should have been growing extensively during the darkest and coldest months in the Southern Hemisphere.

Polar ice loss compounds polar ice loss.  The loss of sea ice increases heat in the polar regions, where temperatures have risen about four times more than the global average.

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Arctic Sea Ice Near Historic Low; Antarctic Ice Continues Decline

Photo, posted September 15, 2016, courtesy of Mario Hoppmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rivers are drying up

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According to a new U.N. report, the world’s rivers had their driest year in at least three decades.  Record heat and droughts in many places contributed to low levels of water in many of the world’s rivers.

The world faces problems of either too much or too little water. The warming climate has fueled both powerful storms with heavy rainfall and intense droughts around the globe. 

Last year was the hottest year on record, and it’s a record that is unlikely to last long.  The Mississippi River and Amazon River basins were at all-time lows.  Major rivers with headwaters in the Himalayas – the Ganges, Brahmaputra, and Mekong Rivers – were all unusually dry.

According to the World Meteorological Organizations State of Global Water Resources Report, nearly half of the nearly 1,000 rivers tracked around the world had below-normal levels of water.  Only 17% had above-average levels.  Over the past 32 years, on average only a quarter of the rivers monitored had below-normal water levels and last-year’s 45% was the largest ever.

Last year’s severe heat shrank glaciers that are a crucial source of meltwater that feeds rivers.  Glaciers lost more ice last year than they have in at least 50 years.

More than half of the world’s population lives within a couple of miles of a body of fresh water.  The places with the highest population densities around the world are almost all near large rivers.  Rivers provide freshwater for irrigation, consumption, and transportation and are an important source of energy. Historically, they have played an important role in the development of human society.  The shrinking of rivers is a big deal.

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World’s Rivers Are Driest They Have Been in Decades

Photo, posted August 22, 2023, courtesy of Radek Kucharski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Megafires and orchard health

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The frequent and massive megafires in places like Canada and the American west have led to a lot of research on the impact of smoke on humans but there has been less study of the effects of smoke on plant health.  Researchers at the University of California, Davis have found that trees are just as vulnerable as humans are to the harmful effects of long-term exposure to smoke.

The Davis researchers studied almond, pistachio, and walnut trees at 467 orchard sites in California’s Central Valley from 2018 to 2022.  In 2022, so-called megafires burned more than 4.2 million acres in California, pouring ash and smoke into the sky.  The researchers had been studying how trees store carbohydrates to cope with heat and drought. 

With the onset of the fires, they saw an opportunity to study how smoke affects carbohydrate levels.  Trees use stored carbohydrates to sustain them through winter dormancy and spring growth.  Trees produce carbohydrates via photosynthesis and thick smoke blocks the amount of light reaching the trees.  Beyond that, there are other aspects of wildfire smoke, such as particulate matter and ozone that appear to affect photosynthesis.

The team found that the smoke not only reduced the amount of carbohydrates in trees but also caused losses that continued even after the fires were extinguished.  This led to nut yield decreases of 15% up to 50% in some orchards.  The researchers expected to see some impact on the trees during periods when smoke was really dense but were not expecting the smoke to have such a lingering effect and result in a significant drop in yield.

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Smoke From Megafires Puts Orchard Trees at Risk

Photo, posted October 1, 2008, courtesy of Suzi Rosenberg 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

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

An electric reactor for industry

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The industrial sector accounts for nearly a third of greenhouse gas emissions in the US, which is more than the annual emissions from cars, trucks, and airplanes combined.  These emissions primarily come from burning fossil fuels to produce goods from raw materials as well as from the chemical reactions associated with production.  Many industrial processes require very high temperatures that are not easily achieved other than by burning fossil fuels.

Researchers at Stanford University have developed and demonstrated a new kind of thermochemical reactor that can generate the huge amounts of heat required for many industrial processes that runs on electricity rather than the burning of fossil fuels.  The researchers claim that the design is also smaller, cheaper, and more efficient than the fossil fuel technology it would replace.

Standard industrial thermochemical reactors burn fossil fuel to heat a fluid that is piped into the reactor, much like the way home radiators work, albeit at far higher temperatures.  The new reactor uses magnetic induction, similar to the way that induction cooktops work.  Heat is transferred by inducing a current into materials that heat up as the current flows.

A proof-of-concept demonstration powered a chemical reaction called the reverse water gas shift reaction and resulted in more than 85% efficiency.  The reaction in question converts carbon dioxide into a valuable gas that can be used to create sustainable fuels. 

The Stanford researchers are working to scale up their new reactor technology and expand its potential applications.  They are working on designs for reactors for capturing carbon dioxide and for manufacturing cement. 

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Electric reactor could cut industrial emissions

Photo, posted October 30, 2022, courtesy of Helmut via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water from thin air

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The Earth’s atmosphere contains enormous amounts of water.  Being able to efficiently and economically extract some of it to provide drinking water would be extremely beneficial to the billions of people across the globe who face chronic water shortages.

There are existing technologies for atmospheric water harvesting – or AWH.  But there are downsides associated with size, cost, and efficiency.   A new device developed by mechanical engineering researchers at the University of Utah has the potential to provide a new drinking water source in arid places.

The device is a compact, rapid-cycling, fuel-fired AWH device.  It relies on adsorbent materials that draw water molecules out of non-humid air and then applies heat to release those molecules into liquid form.

Hygroscopic materials are those that have an affinity for water and soak it up at every opportunity.  Such materials are used, for example, in disposable diapers.  The Utah device makes use of metal organic frameworks, which have enormous amounts of surface area on the molecular scale.

The initial work on the Utah device targeted a small compact water generation unit for soldiers in the field.  Instead of lugging around a large canteen filled with water, the small unit can produce water on demand.  The prototype was able to produce 5 liters of water per day per kilogram of adsorbent material.  Within three days in the field, the system outperforms packing water.  The heat required to precipitate the liquid water was provided by a standard-issue Army camping stove.

Non-military needs are the ultimate application for the device.  The researchers have applied for a patent for what they hope will be a potential solution to a persistent global problem.

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Producing water out of thin air

Photo, posted August 9, 2012, courtesy of Enid Martindale via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cooling cities

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As the climate warms, city dwellers tend to suffer from extreme heat more than people in rural areas because of the urban heat island effect. Extensive surfaces of man-made materials like concrete, asphalt, and brick absorb the sun’s energy and lead to temperatures well above those in the surrounding countryside.

Cities can take countermeasures that include creating urban green spaces full of plants that cool the surrounding air and the use of cool roofs that reflect the sun’s energy back into space.  Local governments in many cities provide incentives for planting more trees.  But more could be accomplished by encouraging the use of cool roofs.

The heat island effect has been well-known for a long time, but scientists are only recently learning what interventions are most effective. A recent study modeled two days of extreme heat in London in 2018 and compared the potential effects of cool roofs, green roofs, roof-top solar panels, and ground level vegetation. They found that cool roofs are the most effective way to lower temperatures and would have reduced London temperatures by 2 degrees on average and as much as 3.6 degrees in some places.

Cool roofs are created by swapping out dark, heat-absorbing roofing materials with reflective materials or simply by painting roofs white. Los Angeles is the first major city to require that all new residential construction includes a cool roof. 

Apart from the effectiveness of passive cooling techniques, using them also reduces the reliance upon air conditioning to protect people from heat.  Air conditioners themselves contribute considerable amounts of heat to urban environments.

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The surprisingly simple way cities could save people from extreme heat

Photo, posted February 21, 2024, courtesy of Warren LeMay 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

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

Geological thermal energy storage

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The electricity grid is increasingly using solar and wind power.  Depending on those two sources requires the ability to store energy to have on hand when the sun isn’t shining and the wind isn’t blowing.   Energy needs to be stored away to be used hours, days, or even weeks after it is produced.

Energy storage is booming.  California has increased its energy storage capacity tenfold in recent times.  One day in April, storage batteries were the largest source of electricity in the state for a period of two hours.  But batteries are not the only way to store energy.  There are chemical, electrochemical, mechanical, and thermal methods that each has potential advantages and unique features.

A project in Kern County, California, is making use of an abandoned oil field to create a long-term energy storage installation.  The plan is to retrofit depleted oil wells to store concentrated solar energy in superheated groundwater for long periods of time.  The stored heat can then be used to drive turbines when electricity is needed.

Some 1,200 feet below the surface of the oil field are pockets of permeable sandstone that have been emptied of the oil they previously contained.   An array of parabolic mirrors will gather solar energy that will heat silicon oil in an underground loop to 700 degrees Fahrenheit.  The oil pipeline will heat up groundwater down below.  When electricity is needed, the heated groundwater will be brought to the surface to operate turbines.

There is no new technology involved.  The individual aspects have never all been combined before, but the likelihood of success is high.  There are lots of depleted oil fields that could be used this way in the future.

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Can a California Oilfield Be Retrofitted to Store Solar Energy?

Photo, posted July 18, 2017, courtesy of John Ciccarelli / BLM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Industrial heat and solar power

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Many industrial processes require extremely high temperatures, typically more than 1,800 degrees Fahrenheit.  This heat is generally produced by burning fossil fuels – either coal or natural gas – which emits large amounts of greenhouse gases. This level of heat cannot be economically produced using renewable electricity.  As a consequence, decarbonizing these industrial processes is very difficult.

Researchers at ETH Zurich in Switzerland have recently demonstrated a new method of obtaining high-temperature heat based on solar radiation.  They have engineered a device called a thermal trap.  It consists of a quartz rod coupled to a ceramic absorber that can efficiently absorb sunlight and convert it to heat.

In laboratory-scale experiments, they exposed a foot-long quartz rod to artificial light 135 times more intensive than sunlight and were able to produce temperatures as high as 1,900 degrees.  The artificial light source was needed to mimic the effects of concentrated solar energy plants that typically make use of large numbers of mirrors to direct intense solar energy onto a small area.

There are already concentrated solar power plants that operate at temperatures as high as 1,100 degrees and use the heat to operate turbines to generate electricity.  These plants lose efficiency at higher temperatures because of radiative heat losses.  The Zurich thermal trap minimizes these losses and permits higher temperature operation.

The hope is that at a large scale, the new approach may make it possible to use solar energy to decarbonize energy-intensive industrial processes.

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Using solar energy to generate heat at high temperatures

Photo courtesy of ETH Zurich / Emiliano Casati.

Earth Wise is a production of WAMC Northeast Public Radio

Record carbon dioxide levels

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Despite the increasing concern about the warming climate, the period between March of last year and March of this year has set a new record for the largest 12-month gain in atmospheric CO2 concentration ever observed.  The new level, measured at Hawaii’s Mauna Loa Observatory was nearly 5 parts per million higher than last year’s level reaching more than 426 parts per million.

CO2 levels averaged 280 ppm for the past 800,000 years until the Industrial Revolution began and people started burning fossil fuels.  Levels started being measured at Mauna Loa in 1958, when they were 315 ppm.  Between 1958 and 2005, the CO2 level rose to 380 ppm.  Over the past 19 years, the amount of CO2 has continued to rise rapidly and with it, global temperatures.

The record increase in carbon dioxide over this past year is probably associated with the end of an El Niño event.  The previous record increase in 2015-2016 was also associated with El Niño.

But the overall trend is clear and discouraging.  Over the past 66 years, the amount of carbon dioxide in the atmosphere has increased by 35%.  This increase is a result of the burning of coal, oil, and natural gas, as well as the effects of deforestation and livestock agriculture.

Carbon dioxide absorbs heat radiating from the Earth’s surface and re-releases it in all directions, including back toward Earth’s surface.  Without this greenhouse effect, the Earth would actually be frozen.  But people are supercharging the natural greenhouse effect and causing the global temperature to rise.  Global energy demand continues to grow and if we continue to meet that demand mostly with fossil fuels, temperatures will continue to rise.

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Scripps Institution of Oceanography: CO2 levels have largest 12-month gain

Photo, posted March 3, 2014, courtesy of Jon Roig via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Recycling cement

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Concrete is the second-most-used material on the planet.  Only water is used more.  Producing concrete is responsible for 7.5% of human-produced carbon dioxide emissions.  So, finding a cost-effective way to reduce these emissions is a major challenge in the face of ever-growing global demand for concrete.

Researchers at Cambridge University have found that used cement is an effective substitute for lime flux, which is an essential material used in steel recycling that results in a waste product called slag.  When lime is replaced with used cement, the end product instead is recycled cement that can be used to make new concrete.

The process does not add any significant costs to concrete or steel production and significantly reduces the emissions associated with both.

Concrete is made from sand, gravel, water, and cement.  Cement is made by a process called clinkering, in which limestone and other materials are heated to 2,600 degrees Fahrenheit.  The process converts the materials into cement but releases large amounts of CO2 as limestone decarbonates into lime. 

Cambridge researchers found that using cement clinker and iron oxide instead of lime works well in steel recycling.  Crushing old concrete and taking out the sand and stone results in a cement that is reactivated by the recycling furnace to produce a material with excellent properties. 

Recent tests by the Materials Processing Institute showed that recycled cement can be produced at scale in an electric arc furnace.  Ultimately, this method could produce zero emission cement if the electricity for the furnace comes from renewable sources.

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Cement recycling method could help solve one of the world’s biggest climate challenges

Photo, posted July 18, 2011, courtesy of Kenta Mabuchi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A month of extra-hot days

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The past 12 months have been the hottest ever measured across the globe.  This may not be everyone’s experience in every location, but the average person on Earth experienced 26 more days of abnormally high temperatures than they would have in the absence of climate change.

Researchers considered a given day’s temperature to be abnormally high in a particular location if it exceeded 90% of the daily temperatures recorded there between 1991 and 2020.  Nearly 80% of the world’s population experienced at least 31 days of abnormal warmth since May of 2023.  Theoretically, the number of unusually warm days would have been far fewer in the absence of global warming.

In some countries, the extra-warm days added up to two or three weeks.  In others, such as Colombia, Indonesia, and Rwanda, there were up to 4 months of them. The average American experienced 39 days of extra-warm temperatures since last May.

Scientists also added up how many extreme heat waves the planet experienced since last May.  These are defined as episodes of unseasonable warmth across a large area, lasting three or more days, and causing significant loss of life or disruption to infrastructure or industry.  In total, the researchers identified 76 such episodes, affecting 90 countries, on every continent except Antarctica.

The world’s climate is now shifting toward the La Niña phase of the cyclical pattern called the El Niño-Southern Oscillation. This usually leads to cooler temperatures on average, but the recent heat could have lingering effects on weather and storms for months to come, including what is expected to be an extraordinarily active Atlantic hurricane season.

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Climate Change Added a Month’s Worth of Extra-Hot Days in Past Year

Photo, posted December 21, 2011, courtesy of Maggie Lin Photography 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

The largest carbon removal plant

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Direct air capture (DAC) is process that removes carbon dioxide out of the air and stores it away where it can no longer trap heat in the atmosphere.  It is intended to be a way of getting rid of the greenhouse gases that have built up in the atmosphere.  In principle, it’s a great idea.  In practice, it is a huge challenge.

In 2017, a company called Climeworks became the first company to take carbon dioxide out of the air and sell it as a product for use in carbonated drinks and in greenhouses.  In 2021, the company opened a DAC plant called Orca in Iceland that captures CO2 and permanently stores it underground.  Clients like Microsoft pay Climeworks for doing this as a way of offsetting their own emissions.

Recently, Climeworks has started operating a new plant called Mammoth – also in Iceland – that will be able to capture about 10 times more carbon dioxide than Orca.  Iceland is a prime location for DAC technology because its abundant geothermal energy makes powering it cheap and environmentally friendly.

Mammoth, when fully operational, will remove about 36,000 tons of carbon dioxide a year, the largest DAC system in the world.  But there is a long, long way to go.  Microsoft alone emits nearly 13 million tons of carbon dioxide a year.

There are multiple DAC projects in development including several in the United States being funded by the Bipartisan Infrastructure Law.  The four DAC hubs being developed under the program are each supposed to have the capacity to capture at least a million metric tons of CO2 a year.

Whether DAC can make a real difference remains to be seen.

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The world’s largest carbon removal plant is here, and bigger ones are on the way

Photo credit: Climeworks

Earth Wise is a production of WAMC Northeast Public Radio

Global coral bleaching

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The world’s coral reefs are in the midst of a global bleaching event being driven by extraordinarily high ocean temperatures.  This is the fourth such global event on record and is predicted to be the largest one ever.  Coral bleaching occurs when corals are stressed by heat and eject the symbiotic algae within them that they need to survive.  Bleached corals can recover if water temperatures cool soon enough.  Otherwise, they die.

Each of the three previous coral bleaching events has been worse than the last.  The first, in 1998, affected 20% of the world’s reefs.  The second, in 2010, affected 35%.  The third, from 2014 to 2017, affected 56% of reefs.

The current bleaching event was confirmed by satellite observations early in April and was already seen to be affecting more than half of the world’s coral areas across the Pacific, Indian, and Atlantic Oceans.  The ongoing event is expected to be the worst bleaching ever experienced by Australia’s Great Barrier Reef.  A small saving grace is that the current bleaching event is not expected to be of extremely long duration because the El Niño in the Pacific has abated.

Coral bleaching events are becoming more severe and frequent due to increased marine heat waves driven by climate change.  Last year was particularly difficult for corals as global sea temperatures reached record high levels for several months.

Widespread coral bleaching impacts economies, livelihoods, food security, and more.  Coral reefs provide ecosystem services essential to marine life and human populations as well.  Global action will be needed for coral interventions and restorations.

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Satellites watch as 4th global coral bleaching event unfolds

Photo, posted March 23, 2012, courtesy of Oregon State University via Flickr.

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