Earth Wise

A look at our changing environment.

You are here: Home / Archives for carbon dioxide

carbon dioxide

Plastic From Sunlight | Earth Wise

By Leave a Comment

Photosynthesis is the process that plants use to turn water, carbon dioxide, and energy from sunlight into plant biomass.  It provides humans and much of animal life with food.  Photosynthesis is also nature’s way of reducing the amount of carbon dioxide in the atmosphere.  The CO2 is not directly stored in plants but rather is combined into organic compounds.

Researchers across the globe are trying to find effective ways to mimic photosynthesis.  One version of artificial photosynthesis seeks to take carbon dioxide and combine it into organic compounds that can be used as raw materials for various kinds of manufacturing. 

A research team in Japan has found a way to synthesize fumaric acid from carbon dioxide using sunlight to power the process.  Fumaric acid is a chemical typically synthesized from petroleum and is used as a raw material for making biodegradable plastics such as polybutylene succinate. 

Much of artificial photosynthesis research is aimed at using solar energy to convert carbon dioxide directly into a fuel rather than a raw material.  Such solar fuels can be produced by a variety of means including thermochemical (using the sun’s heat to drive chemical reactions), photochemical (using the sun’s light to drive chemical reactions), and electrochemical (using solar-generated electricity to drive chemical reactions.)   These approaches generally involve the use of specialized catalysts to drive the desired chemical reactions. 

One way or another, what techniques for artificial photosynthesis have in common is trying to imitate what plant life on Earth has been doing for millions of years. 

**********

Web Links

Artificial photosynthesis uses sunlight to make biodegradable plastic

Photo, posted June 14, 2017, courtesy of Alex Holyake via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cheaper Carbon Capture | Earth Wise

By Leave a Comment

As the years roll by without sufficient progress in reducing carbon dioxide emissions, the need for technologies that can capture CO2 from its sources or remove it from the air becomes stronger and stronger.  People have developed various ways to capture carbon dioxide, but to date, they generally suffer from some combination of being too costly or not being able to scale up to the necessary magnitude.

Scientists at the Pacific Northwest National Laboratory in Richland, Washington recently announced the creation of a new system that they claim is the least costly to date that captures carbon dioxide and turns it into a widely-used chemical: methanol.

Technologies that simply capture carbon dioxide that then needs to be stored in some secure location are difficult to implement from a cost perspective.  The PNNL researchers believe that turning CO2 into methanol can provide the financial incentive for widespread implementation.   Methanol can be used as a fuel, a solvent, or an important ingredient in plastics, paint, construction materials, and car parts.

The system is designed to be installed in fossil fuel-fired power plants as well as cement and steel plants.  Using a capture solvent developed by PNNL, the system grabs carbon dioxide molecules before they are emitted and converts them into methanol. Creating methanol from CO2 is nothing new, but capturing the carbon dioxide and converting into methanol in one continuously flowing system is new.

More work is needed to optimize and scale the process and it may be several years before it is ready for commercial deployment.

**********

Web Links

Scientists Unveil Least Costly Carbon Capture System to Date

Photo, posted November 25, 2022, courtesy of Massachusetts Department of Environmental Conservation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fuel From Wind And Water | Earth Wise

By 1 Comment

Hydrogen is the most common element in the universe and it can be used as a fuel to run cars, trains, and even airplanes.  Using it produces no harmful emissions.  However, to date, the way it is economically produced is not clean and green.  It is made from natural gas and leaves behind lots of carbon dioxide.

Around the world there are many projects working on so-called green hydrogen.  Producing hydrogen by splitting water into its component elements is called electrolysis and produces only oxygen as a waste product.  The problem with electrolysis is that it takes prodigious amounts of energy and therefore is very expensive.

A new project taking place in north Texas hopes to create the country’s first large-scale producer of green hydrogen.  The project is building a 900-megawatt wind farm along with a 500-megawatt solar farm.  The 1.4 gigawatts of total production capacity is more energy than the city of Austin consumes.  That energy will be used to produce 200,000 kilograms of hydrogen a day.

This project is among the largest proposed green hydrogen projects in the U.S.   There are green hydrogen proposals in Europe, Australia, Africa, and the Middle East that range from 10 GW to 67 GW. 

The Texas project, being developed in partnership by Air Products and AES, has been enabled by government support from the Inflation Reduction Act.    

There are a few thousand hydrogen-powered cars, boats, and trains but without substantial, cost-effective hydrogen infrastructure, the market is very limited.   Subsidizing the development of the necessary infrastructure is essential if there is any real chance to create the long-imagined hydrogen economy.

**********

Web Links

Texas Project Will Use Wind to Make Fuel Out of Water

Photo, posted June 5, 2005, courtesy of City Transport Info via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

City Greenery And Carbon Emissions | Earth Wise

By Leave a Comment

According to the United Nations, more than half of the world’s population currently lives in cities.  Projections show that the combination of urbanization and global population growth could add another 2.5 billion people to cities by 2050. 

Unsurprisingly, cities are a major contributor to climate change.  According to U.N. estimates, cities are responsible for 75% of global carbon dioxide emissions, with transportation and buildings being among the largest contributors. 

According to a new study of vegetation across New York City and some adjoining urban areas, photosynthesis by trees and grasses on many summer days absorbs all the carbon emissions produced by cars, trucks and buses, and then some.  In fact, on many summer days, the total carbon uptake in the region equaled up to 40% of a summer afternoon’s total emissions from all sources in the City. The results, which were recently published in the journal Environmental Research Letters, further highlights the critical importance of urban greenery.

Most previous studies have analyzed the carbon uptake of vegetation by looking at the contiguous tracts of green spaces, but this only comprises about 10% of metro areas.  Using detailed aerial radar imagery of New York City that mapped vegetation in unprecedented 6-inch grids, the researchers were able to include the other 90% of the metro area typically left out in most models. 

Since carbon uptake by vegetation only occurs during the growing season, green spaces in cities situated in warmer climates likely play a larger role in carbon uptake. 

As city populations swell around the world, every bit of urban greenery is critical in the fight against climate change. 

**********

Web Links

New York City’s greenery absorbs a surprising amount of its carbon emissions

68% of the world population projected to live in urban areas by 2050, says UN

Photo, posted October 5, 2009, courtesy of David Orban via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Turning Carbon Into Stone | Earth Wise

By Leave a Comment

A start-up company in Oman called 44.01 was recently awarded a $1.2 million Earthshot Prize by Prince William of the U.K.  The company, whose name corresponds to the molecular weight of carbon dioxide, is working on speeding up natural chemical reactions that take carbon from the air and lock it into solid mineral form.

The company’s location in Oman is no random occurrence.  The mountains of northern Oman and along the coast of the United Arab Emirates are the site of a huge block of oceanic crust and upper mantle that was thrust upward some 96 million years ago.  The tilted mass of rock is over 200 miles long and is the largest surface exposure of the Earth’s mantle in the world.

This type of rock, called peridotite, is rich in olivine and pyroxene, which react with water and carbon dioxide to form calcium-based minerals like serpentine and calcite that permanently lock in carbon. Other kinds of rock also are capable of carbon-storing mineralization, but this mantle rock is the most effective for the purpose. It only exists at the Earth’s surface in a few places, including Papua New Guinea and some spots in California and Oregon.

The 44.1 company is planning to use solar-powered direct air capture devices to remove CO2 from the air, use it to produce carbonated water, and inject the water into the reactive rocks.  The company will operate a couple of pilot systems during 2023.  Ultimately, the company believes it can scale up the process to be able to permanently sequester as much as a billion tons of CO2 a year by the year 2040 without needing to inject the gas into deep caverns or find other places to store it.

**********

Web Links

With Major Prize, a Project to Turn Carbon Emissions to Stone Gains Momentum

Photo, posted August 10, 2018, courtesy of JM McBeth via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fertilizing The Ocean | Earth Wise

By Leave a Comment

There are a variety of schemes for removing carbon dioxide from the atmosphere.  Some require advanced and generally not-very-well developed technology.  Others, such as planting vast numbers of trees, are nature-based but are daunting with respect to the scale to which they need to take place in order to be truly effective.

Researchers at the Pacific Northwest National Laboratory in Richland, Washington have been examining the scientific evidence for seeding the oceans with iron-rich engineered fertilizer in order to feed phytoplankton.  Phytoplankton are microscopic plants that are a key part of the ocean ecosystem.

Phytoplankton take up carbon dioxide as they grow.  In nature, nutrients from the land end up in the ocean through rivers and from blowing dust.  These nutrients fertilize the plankton.  The idea is to augment these existing processes to increase the growth of phytoplankton.  As they eventually die, they sink deep into the ocean, taking the excess carbon with them.


The researchers argue that engineered nanoparticles could provide highly controlled nutrition that is specifically tuned for different ocean environments.  Surface coatings could help the particles attach to plankton.  Some could be engineered with light-absorbing properties, allowing plankton to consume and use more carbon dioxide.

Analysis of over 100 published studies showed that numerous non-toxic, abundant, and easy-to-create metal-oxygen materials could safely enhance plankton growth.  According to the researchers, the proposed fertilization would simply speed up a natural process that already sequesters carbon in a form that could remove it from the atmosphere for thousands of years.  They argue that given the current trends in the climate, time is of the essence for taking action.

**********

Web Links

Fertilizing the Ocean to Store Carbon Dioxide

Photo, posted August 2, 2007, courtesy of Kevin McCarthy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mauna Loa Eruption And Climate Tracking | Earth Wise

By Leave a Comment

Mauna Loa, the largest active volcano in the world, erupted for the first time in nearly 40 years in late November.  A 124-foot aluminum tower at the top of the volcano has been the site of carbon dioxide measurements for over 60 years but the eruption cut off power to the site, stopping the monitoring.

Carbon dioxide measurements on Mauna Loa began in 1958.  The project was started by geochemist Charles Keeling and eventually taken over by his son Ralph Keeling upon his father’s death in 2005.  It is the longest continuous record of the rising levels of carbon dioxide in the world.

Mauna Loa is an ideal location for carbon dioxide monitoring because it is a remote location away from both carbon dioxide sources like dense population centers and roads, and carbon sinks like areas of heavy vegetation.

There are hundreds of carbon dioxide monitoring stations around the world, including more than 70 operated by the National Oceanic and Atmospheric Administration, so the interruption will not stop global recordkeeping.  But Mauna Loa holds significant symbolism as the first and most frequently sited source of carbon dioxide data.

There have been other interruptions in the measurements.  Federal budget cuts in 1964 paused them for about 3 months.  A 1984 eruption also cut off power to the facility and shut it down for about a month.

When the facility first started operating, the average carbon dioxide concentration was measured at 313 parts per million.   Most recently, levels have peaked at around 421 parts per million, the greatest concentration in at least 4 million years. 

Power will be restored to the Mauna Loa facility and its measurements will resume.

**********

Web Links

Mauna Loa Eruption Threatens a Famous Climate Record

Photo, posted November 29, 2022, courtesy of L. Gallant / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Europe Is Warming Faster Than The Rest Of The Planet | Earth Wise

By Leave a Comment

A new study by researchers at Stockholm University has found that the warming during the summer months in Europe has been much faster than the global average.  The findings, published in the Journal of Geophysical Research Atmospheres, are that the climate across the European continent has become drier, particularly in southern Europe, leading to worse heat waves and an increased risk of fires.

Warming over land areas occurs much faster than over oceans.  The global average warming to date is 1.6 degrees Celsius over land and 0.9 degrees over oceans.   This means that the global emissions budget to keep warming below 1.5 degrees has already been used up over land.  The new study in fact shows that the emissions budget to avoid 2 degrees of warming has already been exceeded over large parts of Europe during the summer half-year (April to September).

This accelerated warming in Europe has led to more frequent heat waves.  These, in turn, increase the risk of fires, such as the devastating fires in southern Europe this past summer.

Southern Europe has been experiencing a positive feedback situation in which the ongoing warming has been amplified because of drier soil and decreased evaporation.  Added to that, there has been less cloud coverage over large parts of Europe, probably as a result of less water vapor in the air.

The study also looked at the impact of aerosol particles on temperatures in Europe.  As the amount of relatively short-lived aerosol particles has decreased with the reduction of coal-fired power plants, the temporary cooling effects of those particles partially masking the underlying warming trend have diminished.  In contrast, carbon dioxide emissions stay in the atmosphere for centuries.

**********

Web Links

Large parts of Europe are warming twice as fast as the planet on average

Photo, posted April 18, 2020, courtesy of Roman Ranniew via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

It Really Is Greenhouse Gases | Earth Wise

By Leave a Comment

The scientific consensus that human-generated carbon dioxide is changing the climate began to form in the 1980s. 

For a long time, the changes to the climate were simply denied.  After a while, as those changes became increasingly hard to ignore, the argument shifted to the changes being real but not caused by anything people are doing.  The multi-trillion-dollar fossil fuel industry was strongly motivated to focus attention away from the association between carbon dioxide and climate change.

The greenhouse gas effect has been known since the 19th century.  It isn’t just real; it is essential to life on earth.  Without sufficient levels of carbon dioxide in the atmosphere to trap some of the sun’s heat, the earth would be an ice planet incapable of supporting much in the way of life.  But there can be too much of a good thing.

Naysayers continue to grasp at alternative explanations for the warming planet rather than the inconvenient truth.  Some people try to claim that it is the release of heat from all our energy-generating activities -power plants, heaters and air conditioners, vehicles, and so on – that is warming the planet.

That issue has been studied in detail.  Human activity does generate a lot of heat and, technically speaking, that heat does help warm the planet.  However, the sun dumps 10,000 times more heat on the earth than all of human energy production added together.  Just the normal fluctuations in solar energy are 10 times larger than everything we do put together.

What is increasingly warming the planet is not the continuing energy striking the earth; it is primarily the fact that growing levels of greenhouse gases in the atmosphere are trapping more and more of that heat and preventing it from escaping into space.

***********

Web Links

Integrating anthropogenic heat flux with global climate models

Photo, posted August 25, 2009, courtesy of Gerald Simmons via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon In The Congo Peatlands | Earth Wise

By Leave a Comment

The Congo peatlands in central Africa are the world’s largest tropical peatlands complex, occupying an area of 65,000 square miles, about the size of the entire state of Florida. Peatlands represent a huge store of carbon and therefore are important to the stability of the climate.

A study by scientists at the University of Leeds and University College London found that around the time that Stonehenge was built – about 5,000 years ago – there was an extended drying period in central Congo and the peatlands started emitting carbon dioxide rather than storing it.  Over the course of time, the climate in the area got wetter again and over the past 2,000 years, the Congo peatlands have been a place that takes large amounts of carbon out of the atmosphere.

The study utilized peat samples taken from beneath remote swamp forests to build a record of the vegetation and rainfall in the central Congo Basin over the past 17,500 years.

In a paper published in Nature, the researchers warn that if modern-day global warming produces extended droughts in the Congo region, history could repeat itself and the peatlands could once again become carbon emitters.  If that were to happen, over 30 billion tons of carbon could be released into the atmosphere.  That is the equivalent to the total global emissions from fossil fuel burning over a three-year period.

There is some evidence that dry seasons are lengthening in the Congo Basin, but it is unknown if these will continue.  In any case, the study reveals that peatlands are more vulnerable than previously thought and need to be protected.  They are some of the most wildlife and carbon-rich ecosystems on Earth.

**********

Web Links

Congo peatlands could release billions of tonnes of carbon

Photo, posted November 5, 2016, courtesy of Roni Ziade / Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Renewable Energy Booming in India | Earth Wise

By Leave a Comment

India is the country with the second largest population in the world – over 1.4 billion people – second only to China – and will undoubtedly pass China soon based on population trends in the two countries.   India is the third largest emitter of carbon dioxide, after China and the U.S.  With its rapidly growing population and an economy heavily dependent on coal and oil, emissions in India are on a steep upward trajectory.  Currently, fossil fuels account for about 60% of India’s installed energy capacity.  It is essential that actions are taken to curb its rapid increase in greenhouse gas emissions.

To that end, India’s renewables sector is booming.  The country is projected to add 35 to 40 gigawatts of renewable energy each year until 2030.  That’s enough energy to power up 30 million more homes each year.  The country has established a target of producing 50% of its electricity from non-fossil fuel sources by the end of this decade.

 India is expected to reach over 400 gigawatts of renewable energy capacity by 2030

according to the Institute for Energy Economics and Financial Analysis and Climate Energy Finance.  The Indian government’s own projections estimate that the country will reach 500 gigawatts of renewable capacity in that timeframe.

As is the case with China, a country with an enormous population undergoing major economic growth and modernization has vast energy needs.  While it is imperative for the entire world that India puts a cap on its growing greenhouse gas emissions, it is a difficult challenge for an energy-hungry country.

**********

Web Links

Renewable energy booms in India

Photo, posted November 14, 2011, courtesy of Amaury Laporte via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon Capture Booming | Earth Wise

By Leave a Comment

For the world to reach a state of net-zero emissions, it is going to require more than the ongoing transition to renewable energy sources.  There will also need to be efforts to capture the emissions from sources that can’t easily eliminate their pollution.  These include steel mills, cement plants, and other industrial sites.  At least for the foreseeable future,  a number of essential industries have no other viable path to deep decarbonization, and carbon capture and storage projects are the only promising strategy on hand.

Companies use CCS to filter emissions from fossil fuel power plants and industrial facilities and then bury the captured carbon underground, often in deep caverns.

Over the past 12 months, the pipeline for carbon capture and storage projects has grown by 44%.  This year, firms have announced 61 new CCS projects, bringing the total number of commercial projects in the global pipeline to 196, which includes about 30 that are already in operation.  Another 11 are under construction, and 153 are in development.

When all of these projects are completed, they will have the capacity to capture a total of about 270 million tons of carbon dioxide per year.  Estimates are that there need to be 1,400 million tons locked away each year to reach zero-emissions.  So, the existing project pipeline constitutes about 20% of what is ultimately needed.

The recently passed Inflation Reduction Act boosts tax incentives for carbon capture.  Analysts believe this could multiply U.S. deployment of the technology more than 10-fold.  Globally, it is expected that CCS will continue its rapid growth as countries ramp up investments in the technology.

**********

Web Links

Carbon Capture Projects See Meteoric Growth in 2022

Photo, posted August 22, 2022, courtesy of Nenad Stojkovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Trees Are Growing Bigger | Earth Wise

By Leave a Comment

The alarming rate of carbon dioxide flowing into the atmosphere is having a real and actually positive effect on plant life. Higher concentrations of carbon dioxide make plants more productive because photosynthesis makes use of the sun’s energy to synthesize sugar out of carbon dioxide and water.  Plants make use of the sugar both as a source of energy and as the basic building block for growth.  When carbon dioxide levels go up, plants can take it up faster, supercharging the rate of photosynthesis.

In a new study published in the journal Nature Communications, scientists at Ohio State University found that trees are feasting on decades of carbon dioxide emissions and are growing bigger as a result. 

The researchers tracked wood volume in 10 different tree groups from 1997 to 2017 and found that all of them except aspens and birches grew larger.  Over that time period, carbon dioxide levels climbed from 363 parts per million to 405 parts per million.  According to the study, each 1% increase in lifetime CO2 exposure for trees has led to more than a 1% increase in wood volume.

In the big picture, the news isn’t so positive.  The global warming caused by increasing carbon dioxide levels increasingly threatens the forests of the world.  It has led to worsening droughts, insect infestations, and wildfires.  So overall, increasing levels of carbon dioxide are by no means a good thing for the world’s trees.  However, since trees are growing bigger more quickly, it means that planting them is an increasingly cost-effective method for fighting climate change because the same number of trees can sequester more carbon.

**********

Web Links

As Carbon Dioxide Grows More Abundant, Trees Are Growing Bigger, Study Finds

Photo, posted September 12, 2015, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The U.S. Ratifies A Climate Treaty | Earth Wise

By Leave a Comment

In a rare display of bipartisanship, the U.S. Senate voted 69-27 in favor of ratifying a key international climate agreement aimed at curbing global warming.  The Kigali Amendment to the Montreal Protocol, which has been ratified by 137 other countries so far, ends the use of climate-warming hydrofluorocarbons that are 1,000 times more potent than carbon dioxide in warming the atmosphere.   This is the first international climate treaty that the U.S. has joined in 30 years.

The Kigali Agreement was established in Kigali, Rwanda in 2016 to phase out HFCs, which have been the replacements for CFCs (chlorofluorocarbons) in air conditioners and refrigerators.  CFCs were found to be depleting the ozone layers that protects the earth from harmful ultraviolet rays.  HFCs do not deplete the ozone layer, but they have been a significant contributor to global warming.

The U.S. ratification of the treaty is largely symbolic.  The American Innovation and Manufacturing Act, passed by Congress in 2020, gave the EPA authority to regulate HFCs and the agency has already been doing so.  However, the Senate action shows that the U.S. is back on the international climate bandwagon. 

Failure to ratify the Kigali Amendment would have closed segments of the chemical and manufacturing industries to U.S. producers after 2023 because the Montreal Protocol prohibits trade with countries not party to it or its amendments.

Environmental advocates are hopeful that the U.S. can move forward on other climate actions.  A next step would be to focus on methane, the second leading driver of climate change after carbon dioxide.

**********

Web Links

Senate Votes to Ratify the Kigali Amendment, Joining 137 Nations in an Effort to Curb Global Warming

Photo, posted June 13, 2017, courtesy of UNIDO via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Timber Cities | Earth Wise

By 2 Comments

More than half of the world’s population lives in cities and by 2100, this percentage is predicted to be much higher.  This means that more homes will be built with steel and concrete, which both have very large carbon footprints.  According to a study by the Potsdam Institute in Germany, housing a growing population in homes made of wood instead could avoid more than 100 billion tons of carbon dioxide emissions over the remainder of the century.  This is about 10% of the remaining global carbon budget for staying below the 2-degree Celsius climate target.

The study presents the alternative of housing new urban populations in mid-rise buildings – no more than 4-12 stories high – that are substantially made of wood.  Wood is a renewable resource that carries the lowest carbon footprint of any comparable building material.  Trees take up CO2 from the atmosphere to grow.  Producing engineered wood releases far less CO2 than production of concrete and steel and the finished product continues to store carbon.

The study shows that sufficient wood for new mid-rise urban buildings can be produced without a major impact on food production.  The wood would come from timber plantations as well as natural forests.  The study also looked at biodiversity impacts and ways that ecosystems could be protected while still providing the necessary timber.

Overall, the Potsdam study demonstrates that urban homes made out of wood could play a vital role in climate change mitigation based on their long-term carbon storage potential coupled with the reduced utilization of the carbon-intensive concrete and steel industries.

**********

Web Links

Living in timber cities could avoid emissions – without using farmland for wood production

Photo, posted May 24, 2005, courtesy of Stig Anderson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Low Fares Clean German Air | Earth Wise

By Leave a Comment

Germany’s parliament set summer public transport fares at 9 euros a month as a way to slash pollution and reduce imports of Russian oil.   The low price included all buses, trams, subways, and regional trains, effectively lowering prices by more than 90% in some cities.  Berliners saved 98 euros on their monthly travel pass; commuters in Hamburg saved even more.

The program began June 1 and ended August 31.  The bargain rates drove widespread use of public transport and discouraged the use of cars, which already was undesirable due to high gasoline prices.   Over the three-month period, transit authorities sold over 50 million subsidized tickets.  One out of five travelers were using public transport for the first time, according to surveys.

According to an estimate from the Association of German Transport Companies, the program helped to avoid 1.8 million tons of carbon dioxide emissions.  This is roughly equivalent to taking 1.5 million cars off the road for the summer or planting 30 million trees.

The discount transit program had a clearly positive effect on the climate and, obviously, was a source of financial relief for German citizens.  Last year, Germany was the largest buyer of Russian oil in Europe and it wanted to make drastic reductions in its purchases.  The success of the program prompted many to ask for it to be continued.  However, the program cost the government about 2.5 billion euros in reimbursements to transit companies.  The German government has said it would not be extended.

Nonetheless, German policymakers are weighing other proposals for low-cost public transit.  Clearly encouraging people to use public transit pays dividends.

**********

Web Links

Germany’s Cheap Summer Train Fares Prevented 1.8 Million Tons of Carbon Pollution

Photo, posted June 6, 2022, courtesy of 7C0 via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Propane Refrigerants | Earth Wise

By Leave a Comment

About 10% of the world’s total electricity supply is used for air conditioning.  If current temperature trends continue, the energy demands for space cooling will more than triple by the year 2050.  Air conditioning is a double threat to the environment.  Apart from using lots of energy, ACs also make use of halogenated refrigerants that are extremely powerful greenhouse gases.

The most common space cooling appliances are split-air conditioners, which use an indoor unit and an outdoor unit connected by pipes.  These split ACS mostly utilize HCFC-22 and HFC-410 as refrigerants, which have global warming potential scores as high as 2,256 – meaning they trap 2,256 times more heat than carbon dioxide. 

A study by the International Institute of Applied Systems Analysis in Austria has shown that propane is a far better choice as an air conditioning refrigerant.  Its global warming potential is actually less than 1 meaning it traps less heat than carbon dioxide.  According to the study, if air conditioners switched to propane refrigerants, the world would avoid about a tenth of a degree Celsius of additional warming, which is a significant contribution to meeting the goals of the Paris climate agreement.

Propane-based split-ACs are already available commercially in China and India.  Elsewhere, many national regulations prohibit their use, primarily due to codes restricting the use of refrigerants with higher flammability.  Given the increasingly urgent need for climate action, it seems to be time to reconsider regulations on refrigerants.

**********

Web Links

Propane — a solution for more sustainable air conditioning

Photo, posted March 24, 2021, courtesy of Phyxter Home Services via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plant-Based Foods And CO2 Emissions | Earth Wise

By Leave a Comment

We often hear how eating locally-sourced food is a way to minimize the carbon footprint of our diet.  But from a climate impact perspective, this only has a significant impact if transportation is responsible for a large portion of a food’s final carbon footprint.  In many cases, the greenhouse gas emissions related to transportation make up only a small portion of the total emissions from food, and what we eat is far more important.

In general, beef and lamb have the biggest climate footprint per gram of protein.  Plant-based foods tend to have the smallest impact. Pork and chicken are somewhere in the middle. 

According to new research, U.S. food production could reduce its agricultural carbon footprint between 2.5% and 13.5% by embracing plant-based alternatives to beef.  The study, from researchers at Cornell University, Johns Hopkins University, and international partners, found that most of the reduction would be achieved by decreasing the number of cows needed for beef production by two to twelve million animals.  The research was recently published in the journal Lancet Planetary Health.

However, the researchers also found that acting to reduce climate change in this manner could have unintended consequences.  For example, economic models from the research team show that the growth in popularity of plant-based beef could disrupt the agricultural workforce, threatening more than 1.5 million jobs. 

But in the big picture, doing nothing will cost much more than doing something to slow climate change.  Shifting diets away from meat and other animal products and towards more plant-based foods will help shrink carbon footprints and mitigate climate change.  It’s a win-win for the planet and for human health. 

**********

Web Links

Plant-based ‘beef’ reduces CO2 but threatens ag jobs

Photo, posted November 27, 2018, courtesy of Sarah Stierch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

California Trees Are Dying | Earth Wise

By Leave a Comment

California relies on extensive forests to help reduce the amount of carbon dioxide entering the atmosphere.  But extensive drought and increasingly frequent wildfires have been reducing the state’s tree population for the past three decades.

A comprehensive study by a team of scientists from the University of California Irvine used satellite data to study vegetation changes between 1985 and 2021.  Across the entire state, tree cover area has declined 6.7% over that time period.  The results varied from region to region across the state.

Southern California exhibited the sharpest decline, where 14% of the tree population in local mountain ranges vanished, potentially permanently.  In the Sierra Nevada mountains, tree populations were relatively stable until about 2010.  After that, a severe drought followed by historically large wildfires resulted in a 8.8% die-off of trees.  The northern parts of the state, with higher rainfall and cooler temperatures, fared better, being able to more easily recover from wildfires.

The study goes beyond measuring the tree population of the state and its effects on carbon storage.  The data is also important for understanding how changes in forest cover affects water resources and fire behavior in the state.

The decline of trees in California is affecting the carbon storage abilities of the state.  The satellite survey showed that as the tree populations have dropped, the state’s coverage of shrubs and grasses has risen, possibly indicating that permanent ecosystem shifts are occurring.  The forces contributing to the decline of trees in California are not going away any time soon.  As a result, the threat to California’s ability to mitigate the effects of climate change continues to grow.

**********

Web Links

UCI study: California’s trees are dying, and might not be coming back

Photo, posted March 24, 2016, courtesy of David Fulmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Progress On Artificial Photosynthesis | Earth Wise

By Leave a Comment

Photosynthesis is the process by which plants use the energy from sunlight to turn water and carbon dioxide into biomass and ultimately the foods we and other organisms eat.  Scientists at the University of California Riverside and the University of Delaware have found a way to create food from water and carbon dioxide without using biological photosynthesis and without needing sunlight.

The research, recently published in the journal Nature Food, uses a two-step electrocatalytic process to convert carbon dioxide, electricity, and water into acetate, which is the primary component of vinegar.   Food-producing microorganisms then consume the acetate in order to grow.   Solar panels are used to generate the electricity to power the electrocatalysis.  The result is a hybrid organic-inorganic system that is far more efficient in converting sunlight into food than biological photosynthesis.

The research showed that a wide range of food-producing organisms can be grown in the dark directly on the acetate output of the electrolyzer.  These include green algae, yeast, and the fungal mycelium that produce mushrooms.   Producing algae with this technology is about 4 times more energy efficient than growing it with photosynthesis.  Yeast production is about 18 times more energy efficient than the typical method of cultivating it using sugar extracted from corn.

Artificial photosynthesis has the potential to liberate agriculture from its complete dependence on the sun, opening the door to a wide range of possibilities for growing food under the increasingly difficult conditions imposed by the changing climate.

**********

Web Links

Artificial photosynthesis can produce food without sunshine

Photo, posted September 7, 2016, courtesy of Kevin Doncaster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)