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Buildings and birds

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Birds face a wide range of dangers.  Billions of them each year face violent deaths.  Concerned individuals point at such things as wind turbines, which in fact do kill hundreds of thousands of birds.  But the great majority of bird deaths are caused by cats.  And that’s a danger that isn’t going to go away.

The second largest cause of bird deaths is collisions with building windows.   Building collisions kill hundreds of millions of birds each year in the U.S. alone.  As other places have seen glass skyscrapers proliferate, such as in Chinese cites, these collisions have become a major global factor in bird mortality.

There are growing efforts across the U.S. and Canada to reduce bird collisions.  Many businesses are taking part in “lights out” programs in which their buildings dim lights during spring and fall migrations.  Some buildings now use special glass that birds can see and avoid.  Some communities even have adopted ordinances that require bird-friendly glass in new construction.  Keeping bird attractants away from windows is another important way to reduce bird strikes.  All these measures have been proven to be effective in reducing the number of bird collisions.

 Companies sell vinyl film with tiny dots that can be affixed to windows.  Both businesses and homeowners have seen substantial reduction in bird collisions with such films installed.

Bird collisions are not a new problem but is one that wasn’t really taken seriously until at least the 1970s.  There isn’t much to be done about the greatest threat to birds – namely cats – but how buildings are constructed and operated is something we can control.

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As Bird Kills from Buildings Mount, Cities Look for Solutions

Photo, posted December 24, 2017, courtesy of Nicolas Vollmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Upcycling Plastic Waste | Earth Wise

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People have generated 8 billion tons of plastic waste over time and less than 10% of it has been recycled.  Millions of tons of it escapes into the oceans.  Plastic piles up virtually everywhere on earth.

There are many approaches to dealing with the plastic waste problem and no one of them is a magic bullet.  Engineers at Stanford University have investigated the prospects for upcycling plastic waste for use in infrastructure like buildings and roads.

They used a mix of computer modeling, scientific research, experimental and field data to analyze the potential for using plastic waste in infrastructure.

Among their findings is that recycled glass fiber reinforced polymer composite – which is a tensile plastic commonly used in car, boat, and plane parts – is a promising material for reuse in buildings. 

Roads in which waste plastic is melted down and mixed with conventional paving materials are becoming more common around the world.  India has installed over 60,000 miles of these roads.  Studies show that roads containing waste plastic have the potential to perform better than conventional roads.  They can last longer, are more durable, can tolerate wide temperature swings, and are more resistant to water damage, cracking, and potholes.  Such roads rely less upon virgin fossil resources, which is obviously advantageous.

Upcycling plastic waste in infrastructure is attracting increasing interest because it creates value from something that is strictly a liability and may end up having regulatory advantages as societies move toward more environmentally friendly and sustainable policies.

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Can we use plastic waste to build roads, buildings, and more?

Photo, posted October 7, 2022, courtesy of the Grand Canyon National Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geothermal Energy Storage | Earth Wise

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About 12% of the energy consumed by humanity is used to heat and cool homes and businesses.  A study by researchers at Lawrence Berkeley National Laboratory and Princeton University looked at a novel approach to making use of underground water to maintain comfortable temperatures and reduce consumption of natural gas and electricity.

The idea is to use aquifer thermal energy storage (known as ATES) to provide both heat in the winter and cooling in the summer.  The concept leverages the heat-absorbing property of water and natural geological features.  The idea is to pump up water from existing underground reservoirs and heat it at the surface using environmental heat or even excess energy from solar or wind generation.  Then the warm water is pumped back down. It stays warm for a long time – even months – because the earth is a good insulator.  When the water is pumped back up in the winter, it is much hotter than the ambient air and can be used to supply heat to buildings.

Alternately, water can be pumped up and cooled in the winter and then put back down underground and stored until cooling is needed in the summer months.

This technology has not been used much in the US, but it is gaining recognition internationally, particularly in the Netherlands.  It can perform very well in areas with large seasonal fluctuations.

The research study used modeling and various simulations to estimate how much energy ATES could save on the US grid.  The results showed that adding ATES to the grid could reduce consumption of petroleum products for heating and  cooling by up to 40%.  The system could also help prevent blackouts by reducing high power demand during extreme weather events.

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Underground Water Could be the Solution to Green Heating and Cooling

Photo, posted February 19, 2012, courtesy of Sanjay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

City Greenery And Carbon Emissions | Earth Wise

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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. 

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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

Renewables Will Overtake Coal | Earth Wise

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According to a recent report by the International Energy Agency, worldwide growth in renewable power capacity is set to double in the next five years.  In fact, by 2027, the world will add as much renewable power as it did over the previous 20 years.

Of particular significance is that renewables are going to overtake coal as the largest source of electricity generation by early 2025.

The global energy crisis triggered by the war in Ukraine has had multiple effects on the evolution of the energy system.  While the war has driven a resurgence in fossil fuel consumption in Europe in order to replace gas from Russia, that resurgence is expected to be short-lived.  Instead, the current energy crisis may turn out to be an historic turning point toward a cleaner and more secure energy system.

Soaring fossil-fuel prices triggered by the war have caused many countries to respond by embracing wind turbines, solar panels, nuclear power plants, hydrogen fuels, electric vehicles, and electric heat pumps.  In the US, Congress approved more than $370 billion in spending for clean energy technologies as part of the Inflation Reduction Act.  China, India, South Korea, and Japan have all increased their national targets for renewable power.   However, heating and cooling buildings with renewable power remains a sector needing larger improvement, according to the energy agency.

Overall, the expansion of renewable power over the next five years is now projected to happen much faster than what was projected just one year ago. The new IEA report revised last year’s forecast for renewables growth by 30% as a result of the introduction of new policies by many of the world’s largest greenhouse gas emitters.

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Renewables Will Overtake Coal by Early 2025, Energy Agency Says

Photo, posted March 8, 2021, courtesy of Stanze via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Windows To Cool Buildings | Earth Wise

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About 15% of global energy consumption is for cooling buildings.  Because of this, there is an ever- growing need for technologies that can more efficiently cool buildings.   Researchers at Notre Dame University have used advanced computing technology and artificial intelligence to design a transparent window coating that is able to lower the temperature inside buildings without using any energy.

The idea is to create a coating that blocks the sun’s ultraviolet and near-infrared light, which are parts of the solar spectrum that otherwise pass through glass and help to heat an enclosed room.  Cooling needs can be reduced further if the coating can radiate heat from the surface of the window so it can pass through the atmosphere into space.  Designing a coating that does both of those things simultaneously while transmitting visible light is difficult.  Coatings should not interfere with the view out the window.

The Notre Dame researchers used advanced computer modeling to create a so-called transparent radiative cooler that meets these goals.  The coating consists of alternating layers of common materials like silicon dioxide, silicon nitride, and aluminum oxide or titanium dioxide on top of a glass base and topped with a film of polydimethylsiloxane.  The computing method was able to optimize this structure far faster and better than conventional design techniques.

The researchers say that in hot, dry cities, the coating could potentially reduce cooling energy consumption by 31% compared with conventional windows.  The same materials could be used in other applications, such as car and truck windows.  In addition, the quantum computing-enabled optimization method used for this work could be used to design other composite materials.

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Clear window coating could cool buildings without using energy

Photo, posted September 6, 2015, courtesy of Robert Otmn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sinking Cities | Earth Wise

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Sea levels across the globe are rising as a result of the changing climate.  Two factors are largely responsible: the melting of ice sheets in the polar regions and the fact that as the oceans get warmer, the water in them expands.  

Estimates are that by 2050, there will be over 800 million people living in 570 cities that will be at risk from rising sea levels.   The rising waters can drown neighborhoods, put people’s lives at risk, and wreck entire economies.  Unless global emissions can be reduced sufficiently, sea levels will continue to rise.

A new study, published in the journal Nature Sustainability by Nanyang Technical University in Singapore in collaboration with the University of New Mexico, ETH Zurich, and NASA’s Jet Propulsion Lab, has focused on yet another aspect of the threat to coastal cities.  They have found that many densely populated coastal cities worldwide are even more vulnerable to sea level rise because much of their land is sinking. 

The researchers processed satellite images of 48 cities from 2014 to 2020 using a system called Interferometric Synthetic Aperture Radar.  They found that land subsidence varied on a neighborhood and even individual block level but across all the cities studied, there was a median sinking speed of 6/10” a year.  Some places had land that is sinking at 1.7” per year.  Meanwhile, the global mean sea-level rise is about .15” per year.

The increasing prevalence of industrial processes such as the extraction of groundwater, and oil and gas, along with the rapid construction of buildings and other urban infrastructure are leading to the sinking of the urban areas. 

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Rapid land sinking leaves global cities vulnerable to rising seas

Photo, posted October 24, 2015, courtesy of Jeffrey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global Stilling | Earth Wise

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During the summer of 2021, much of Europe experienced a “wind drought” – wind speeds in many places were about 15% below average.  In the UK in particular, winds were unusually calm and wind energy production was dramatically reduced.

Globally, wind speeds have been dropping by about 2.3% per decade since the 1970s.  In 2019, however, global average windspeeds actually increased by about 6%.  The question is whether a trend of slowing winds – so-called global stilling – is associated with climate change or is just natural variability in action.

Wind results from uneven temperatures in air masses.   Much of the world’s wind comes from the difference between the cold air at the poles and the warm air at the tropics.  Because the Arctic is warming much faster than the tropics, it is possible that winds will continue to decline around the world. 

Another factor people cite is the increase in surface roughness.  The number and size of urban buildings continues to increase, which acts as a drag on winds.

Some models predict that wind speeds will decrease over much of the western U.S. and East Coast, but the central U.S. will see an increase.  Experts do not all agree about what is happening with global winds.  Many believe that the observed changes to date have been within the range of variability.  Furthermore, some places have been windier than usual.

All of this really matters for many reasons.  Europe is increasingly dependent upon wind power as an alternative to fossil fuels.  A 10% drop in wind speed results in a 30% drop in energy generation.   Whatever their cause may be, wind droughts cannot be ignored.

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Global ‘Stilling’: Is Climate Change Slowing Down the Wind?

Photo, posted June 28, 2008, courtesy of Patrick Finnegan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Colorful Solar Panels | Earth Wise

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More and more buildings and public spaces are incorporating solar panels and not only just on rooftops.  Some buildings are incorporating power-generating structures all over their facades.

Using solar panels in this way puts some design constraints on buildings because solar panels are typically a deep black color.  This is because solar panels need to absorb light and making them any other color decreases their ability to do so and generate power.  But the problem is that people don’t necessarily want a black building.

One alternative to traditional solar panel design is to use structural sources of color that include microscopic shapes that only reflect specific light frequencies, like the scales on butterfly wings.  But this approach generally leads to iridescence – which might not be what is wanted – and is often quite expensive to implement.

A team of researchers at a university in Shanghai has now demonstrated a way to give solar panels color that is easy and inexpensive to apply and that does not reduce their ability to produce energy efficiently.

The technique involves spraying a thin layer of a material called a photonic glass onto the surface of solar cells.  The photonic glass is made of a thin, disorderly layer of dielectric microscopic zinc sulfide spheres.  Even though most light can pass through the photonic glass, certain colors are reflected back, depending on the sizes of the spheres.  By varying that size, the researchers created solar panels that were blue, green, or purple with only a very small drop in solar panel efficiency.

The solar panels made this way maintained their color and performance under durability testing.  With this new technology, there may soon be colorful solar panels on our buildings.

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Colorful solar panels could make the technology more attractive

Photo, posted December 15, 2021, courtesy of Pete via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar Windows | Earth Wise

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Solar windows are an attractive idea.  It is very appealing to have the vertical surfaces on the outside of almost any building generate electricity.  The challenge is to have a transparent window be able to function as an efficient-enough solar panel.

Most conventional solar panels use silicon solar cell technology, which is not based on a transparent material.  Transparent solar cells use dye-sensitized technology, which has been the subject of research for decades but has yet to achieve widespread use.

Researchers at the University of Michigan have recently published work on a new process to manufacture solar windows that can be large (over six feet in each dimension) and efficient at electricity production.

The windows make use of dye-sensitized cells which are connected to lines of metal so small that they are invisible to the naked eye.  The individual cells are fairly small but the connection technology allows the construction of large windows.

The solar window has an efficiency of 7%, meaning 7% of incoming sunlight energy is converted to electricity.  The researchers believe that 10% efficiency should be attainable with their technology.  Conventional solar panels have efficiencies of 15% or more.

However, the goal is not necessarily to compete with silicon solar panels.  The real opportunity is to be able to generate electricity when rooftop solar is not practical or to produce additional electricity even when there is already a solar roof.

Going forward, the goals of solar window development are to increase efficiency and to reduce costs to where installing the windows is economically attractive.  Estimates are that the windows currently would cost about twice as much as a conventional window but would pay for the difference in two to six years depending on such things as the level of sun exposure.

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Inside Clean Energy: What’s Hotter than Solar Panels? Solar Windows.

Photo, posted April 17, 2017, courtesy of Shelby Bell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Homes In The Netherlands | Earth Wise

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The Netherlands is a country that is largely built on reclaimed land and a third of it remains below sea level.  The Dutch have long experience with dealing with rising waters.  The city of Amsterdam has almost 3,000 houseboats in its canals.

As sea levels continue to rise across the globe, it is no surprise that the Dutch have taken the lead in creating communities composed of floating houses and buildings.

A floating house is a structure fixed to the shore, often resting on steel poles, and usually connected to the local sewer system and power grid.  They are much like ordinary houses except that instead of a basement, they have a concrete hull that acts as a counterweight, allowing them to remain stable in the water.

The ones in the Netherlands are often prefabricated, square-shaped, three-story townhouses.  Rotterdam, which is 90% below sea level, is home to the world’s largest floating office building as well as a floating farm.

Floating buildings have their challenges, not the least of which are the effects of severe wind and rainstorms, or even the passing of large ships which can make the buildings rock.  Infrastructure like electricity and sewer service is not that simple to implement for the buildings.  But the benefits of floating buildings may outweigh the costs.

For cities facing worsening floods and a shortage of buildable land, floating homes are a potential solution for expanding urban housing in the age of climate change.  Dutch engineers are spearheading floating building projects in Britain, France, and Norway, as well as in threatened island locations like French Polynesia and the Maldives.

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Embracing a Wetter Future, the Dutch Turn to Floating Homes

Photo, posted May 23, 2007, courtesy of Jeff Hutchison via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Living Walls | Earth Wise

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Green roofs are popular in many European countries.  A green roof is a layer of vegetation planted over a waterproofing system installed on a flat or slightly sloped roof.  Such roofs provide shade, remove heat from the air, and reduce temperatures of the roof surface, reducing energy use in the building and diminishing the urban heat-island effect.

A recent study by the University of Plymouth in the UK looked at the effectiveness of living walls – essentially the equivalent of a green roof located on the wall of a building.

The study looked at the effect of retrofitting an existing masonry wall with an exterior living wall façade consisting of a flexible felt fabric sheet system with pockets holding soil in which plants could grow.

Five weeks of measurements demonstrated that the amount of heat lost through the retrofitted wall was 31.4% lower than that of the original structure.  They also found that daytime temperatures within the newly covered section remained more stable than the area with exposed masonry, so that less energy was required to heat that area.

The concept of living walls is fairly new but could be valuable in temperate climates such as Great Britain.  Buildings in the UK account for 17% of greenhouse gas emissions and space heating accounts for 60% of all the energy used in buildings.  So, improving the thermal performance of buildings would have a significant effect on reducing energy use and therefore emissions.

So-called green infrastructure, including green roofs and living walls, provides a nature-based solution that can help tackle climate change, air pollution, and other modern urban problems.

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Living walls can reduce heat lost from buildings by over 30%, study shows

Photo, posted June 19, 2011, courtesy of Linda Hartley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildfires And The Climate | Earth Wise

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Scientists from the National Center for Atmospheric Research recently published a study analyzing the events that influenced the world’s climate in 2020.  Among these were the pandemic-related lockdowns that reduced emissions and resulted in clearer air in many of the world’s cities.

While this was a significant event, the study found that something entirely different had a more immediate effect on global climate:  the enormous bushfires that burned in Australia from late 2019 to 2020, producing plumes of smoke that reached the stratosphere and circled much of the southern hemisphere.

Those fires sprung up in September 2019 and lasted until March 2020.  The fires burned more than 46 million acres (about 72,000 square miles), which is roughly the same area as the entire country of Syria.  Thousands of homes and other buildings were lost.

Major fires inject so many sulfates and other particles into the atmosphere that they can disrupt the climate system, push tropical thunderstorms northward from the equator, and potentially influence the periodic warming and cooling of tropical Pacific Ocean waters known as El Nino and La Nina.

According to the study, the COVID-19 lockdowns actually had a slight warming influence on global climate, as a result of clearer skies enabling more heat to reach the earth’s surface.  In contrast, the Australian bushfires cooled the Southern Hemisphere because the atmospheric particles reflected some of the incoming solar radiation back to space.

This summer, there have been raging wildfires in the western US and Canada, which have affected air quality in many parts of the nation and have been a serious health hazard.  Undoubtedly, these fires are influencing the climate system as well in ways that we are still trying to understand.

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Bushfires, not pandemic lockdowns, had biggest impact on global climate in 2020

Photo, posted January 18, 2020, courtesy of BLM-Idaho via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Soaring Heat And Inner-City Neighborhoods | Earth Wise

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The record-breaking heatwaves this summer have exposed the special vulnerability inner cities have to the effects of summer heat.  Climate change has exacerbated and supercharged heatwaves, as was seen in Seattle and Portland in late June.

Urban cores can be 10 degrees or more warmer than the surrounding countryside.  The urban heat island effect is a result of how cities are built, with so much pavement, so many buildings, and not enough trees.  On top of this, decades of disinvestment in neighborhoods where people of color live have left them especially vulnerable to heat as their homes are not able to cope with it.

In New York City, some residents of Hunts Point in the Bronx keep lists of neighbors they check on to help keep the most vulnerable alive during heat waves.  The city has subsidized 74,000 air conditioners for low-income, elderly residents, and is spending millions to plant trees.  In Phoenix, the hottest big city in the country, officials are working to develop new models for cooler public housing and cooling for streets and pedestrian corridors.

A study, published in 2020, looked at the linkage between higher heat island temperatures and past practices of redlining, where home loans and insurance were unavailable to people in neighborhoods of color.  In 94 of 108 communities studied, the formerly redlined neighborhoods had higher surface temperatures.

Cities are confronted with two heat problems:  emergencies that require immediate action to save lives, and long-term issues related to combating soaring temperatures in heat islands strengthened by global warming. In many cases, cities are not prepared for either problem.  Dealing with and adapting to heat is essential to the long-term viability and quality of life in our cities.

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A Triple Whammy Has Left Many Inner-City Neighborhoods Highly Vulnerable to Soaring Temperatures

Photo, posted May 27, 2014, courtesy of Dan DeLuca via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Strategies To Cool Off Cities | Earth Wise

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Heatwaves in cities are becoming increasingly common and increasingly intense.  The warming climate is a big factor, but it is the nature of our cities that really drives up temperatures.  Solar radiation stored throughout the day on asphalt and buildings is released slowly during the night, which generates significant heat stress.

A study carried out by a major Barcelona university and published in the journal Urban Climate looked at the effectiveness of various ways to mitigate the heating effects in cities.  In particular, the study examined the effects of the use of white roofs on buildings and the expansion of urban green areas with daily irrigation in the Barcelona metropolitan area.  It simulated various scenarios incorporating combinations of these two mitigation strategies.

The strategy with the greatest impact was a combination of the use of both white roofs and the addition of six urban parks, which is a target set by the Barcelona Urban Master Plan.  This scenario resulted in an average temperature reduction of 2.25 degrees Fahrenheit.  The maximum reduction occurs during the mid-afternoon with a reduction of 7 degrees and the combination still provides more than 3 degrees of reduction at 9 pm.  Reducing temperatures this way also results in a reduction in energy consumption, with 26% less spending on air conditioning.

The 2-pronged strategy combines the benefits of reducing the temperature at night due to more urban green areas with the reduction of daytime heat due to both the increased reflectivity of white roofs as well as the irrigation of the green areas.

The study demonstrates how modeling efforts can help urban planners to counteract the impacts of heatwaves, which are likely to increase with climate change and intensification of urbanization.

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White roofs and more green areas would mitigate the effects of heat waves in cities

Photo, posted January 16, 2011, courtesy of Sean MacEntee via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Ozone Recovery Back On Track | Earth Wise

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In 2019, we reported that new emissions of chlorofluorocarbons from eastern Asia were threatening the recovery of the ozone layer in the upper atmosphere.  An unexpected spike in CFC emissions was threatening to undo the progress made under the Montreal Protocol, the international treaty under which every country in the world agreed to phase out the production and use of the ozone-eating chemicals by 2010.

In 2018, a team of scientists reported the spike in emissions of the particular formulation CFC-11 that began in 2013.  By 2019, a second team reported that a significant portion of the emissions could be traced to the Shandong and Hebie provinces in China where there were small factories using the chemical to manufacture foam insulation used in refrigerators and buildings.

Recently, in two papers published in Nature, the same two research teams reported that the global annual emissions of CFC-11 into the atmosphere have declined sharply.   They traced a substantial fraction of the global emission reductions to the very same regions of eastern China where they had previously reported the original spike. 

The results are very encouraging.   If CFC-11 emissions had continued to rise, or even just level off, there would have been real problems with ozone depletion.  Two independent global monitoring networks – one operated by the National Oceanic and Atmospheric Administration and one led by MIT called the Advanced Global Atmospheric Gases Experiment – are doing a good job of detecting threats to the world’s protective ozone layer.  However, the Chinese sources only accounted for about half of the CFC-11 entering the atmosphere.  We still don’t know where the rest of it is coming from.

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Reductions in CFC-11 emissions put ozone recovery back on track

Return of an Old Threat

Photo, posted July 29, 2015, courtesy of NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Path To Net Zero | Earth Wise

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Reaching net zero emissions is both feasible and affordable, according to researchers at the Department of Energy’s Lawrence Berkeley National Laboratory, the University of San Francisco, and consulting firm Evolved Energy Research.   The researchers created a detailed model of the entire U.S. energy and industrial system to produce the first detailed, peer-reviewed study of how to achieve carbon neutrality by 2050.

The study analyzed multiple feasible technology pathways based on very different assumptions of remaining fossil fuel use, land use, consumer adoption, nuclear energy, and biofuel use.  What they had in common was increasing energy efficiency, transitioning to electric technologies, utilizing clean electricity (especially wind and solar power), and deploying small amounts of carbon capture technology.

The decarbonization of the U.S. energy system is an infrastructure transformation.  Getting to net zero by 2050 means adding many gigawatts of wind and solar power plants, new transmission lines, a fleet of electric cars and light trucks, millions of heat pumps to replace conventional furnaces and water heaters, and more energy-efficient buildings.

The various pathways studied have net costs between 0.2% and 1.2% of GDP, which is as little as $1 per person per day.  The cost variations come from various tradeoffs such as the amount of land given to solar and wind farms as well as the amount of new transmission infrastructure required. 

A key result of the study is that the actions required over the next 10 years are similar among all the pathways.   We need to increase the use of renewable energy and make sure that all new infrastructure, such as cars and buildings are low carbon.

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Getting to Net Zero – and Even Net Negative – is Surprisingly Feasible, and Affordable

Photo, posted July 12, 2010, courtesy of Tom Shockey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Do Forests Grow Better With Our Help? | Earth Wise

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Tree planting has become a worldwide cause.  International calls to plant a trillion trees to combat climate change have led to multiple initiatives by countries around the world.  Even the current U.S. administration, with support from businesses and nonprofits has promised to plant over 800 million trees across an estimated 2.8 million acres.  Planting trees is widely seen to be a vital nature-based solution to climate change; a way of moderating its effects as the world works to reduce carbon emissions.  However, recent studies have created some pushback from that view.

The new studies are not opposed to trees.  What they have revealed is that allowing forests to grow back naturally is a better strategy than planting trees.  The new data has shown that, among other things, estimates of the rate of carbon accumulation by natural forest regrowth have on average been 32% too low and, for tropical forests, have been 53% too low.

A new study published in Nature identified 1.67 billion acres that could be set aside to allow trees to regrow.  It excludes land under cultivation or built on, along with various existing valuable ecosystems. 

Natural regrowth allows nature to select which tree species take hold and turns out to happen quite rapidly and in a widespread manner.  The great thing about natural restoration of forests is that it often requires nothing more than human inaction.  Because it requires no policy initiatives, investments, or oversight, data on its extent is rather scarce.  But the data we have reveals that wherever forests have been allowed to recover on their own, it appears to happen rapidly and with great success.

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Natural Debate: Do Forests Grow Better With Our Help or Without?

Photo, posted September 5, 2015, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar On Commercial Buildings | Earth Wise

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The United States installed 3.6 gigawatts of photovoltaic solar capacity in the first quarter of this year to reach a total installed capacity of 81.4 GW.  That is enough to power about 16 million American homes.  More than 2/3 of that capacity has been installed during the past five years.  

There has been a boom in solar installations in recent years and, until the Covid-19 pandemic stuck, 2020 was expected to be the biggest year yet.  Now the unprecedented health, social, and economic conditions in our country creates great uncertainty in such forecasts.

Nevertheless, the opportunities for growth in solar power continue to be substantial.  A new report from the energy research firm Wood Mackenzie looked at the prospects for using the roof space of commercial buildings for solar power.

Currently, just 3.5% of commercial buildings in the U.S. have solar panels on their roofs.  Another 1% of those buildings are attached to solar projects located off-site.  The report looked at how many buildings are potential targets for solar projects.

After accounting for buildings that are too small or that use too little electricity to make solar power a worthwhile investment, the report estimated that 70% of commercial buildings in the U.S. – amounting to some 600,000 sites – are candidates for solar installations.  Doing this would provide 145 GW of new solar capacity, which is nearly twice as much as currently exists in this country. 

Commercial solar installations have their own unique logistical and financial challenges.  While utility solar can scale to lower costs and residential solar has financing opportunities, commercial solar has neither.  But ultimately, it represents an important opportunity for our future energy system.

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U.S. Commercial Rooftops Hold 145 Gigawatts of Untapped Solar Potential

Photo, posted June 25, 2014, courtesy of Rob Baxter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Better Paint For Cooler Buildings | Earth Wise

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A research team led by scientists at UCLA have developed a super-white paint that reflects as much as 98% of incoming heat from the sun.  Such paint, if used on rooftops and other parts of buildings, could have a major impact on reducing the costs of keeping buildings cool.

Passive daytime radiative cooling is a well-known method to keep buildings cooler.  By having building surfaces reflect sunlight and radiate heat into space, building temperatures can be significantly lowered.  This in turn cuts down on air conditioner use and associated carbon emissions.

A roof painted white will result in lower indoor temperatures than a darker roof.  But a white roof will do even more:  it can reject heat at infrared wavelengths that are invisible to our eyes.  This results in even more radiative cooling.

The best performing white paints currently available reflect about 85% of incoming solar radiation.  The rest is absorbed by materials in the paint.  The new research has identified simple modifications in paint ingredients that lead to a major increase in reflectivity.

Current reflective white paints use titanium dioxide, which absorbs UV radiation and therefore heats up under sunlight.  The researchers studied replacing it with other substances such as barite – an artist’s pigment – or with powdered Teflon, both of which allow the paint to reflect more of the sun’s radiation. 

Many cities are encouraging the use of cool-roof technologies on new buildings.  Using the most reflective coatings possible on rooftops, if applied on a sufficiently large scale, could have a real impact on climate change as well as saving significant amounts of energy used for running air conditioners in buildings.

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UCLA-led Team Develops Ways to Keep Buildings Cool with Improved Super White Paints

Photo, posted August 15, 2012, courtesy of Flickr.

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