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Category Archives: Environment

Charts: Top Five Plastic Polluter

The international network Break Free from Plastic, which aims to solve plastic pollution, has recently released the 2022 edition of the “Plastic Pollution Company Survey”. In the survey, volunteers around the world picked up plastic waste in the sea and rivers and tabulated by brand.


Source : Break Free From Plastic

Chart: The World’s Uneven CO₂ Footprint

Source : Statista

Chart: Production-based CO₂ Emission Per Capita of Selected Countries

Source : Chartr

There Might Be a Perfect Indoor Humidity to Curb COVID Spread

Dennis Thompson wrote . . . . . . . . .

It’s sort of like the Goldilocks principle — a room that’s either too dry or too humid can influence transmission of COVID-19 and cause more illness or death, Massachusetts Institute of Technology researchers say.

Maintaining an indoor relative humidity between 40% and 60% is associated with lower rates of COVID-19 infections and deaths, they reported Nov. 16 in the Journal of the Royal Society Interface.

Indoor conditions outside that range are associated with worse COVID outcomes, according to the report.

“There’s potentially a protective effect of this intermediate indoor relative humidity,” said lead author Connor Verheyen, a doctoral student in the Harvard-MIT Program in Health Sciences and Technology, in Cambridge, Mass.

The research team noted that most people are comfortable between 30% and 50% relative humidity. An airplane cabin is kept around 20%.

Until now, researchers have considered that COVID-19 could be influenced by the seasons, but they tended to examine the virus’ patterns in the context of outdoor weather conditions.

The MIT team decided that other researchers might be looking in the wrong direction, given that people in most places spend more than 90% of their time indoors. Indoor conditions also are where most viral transmission occurs.

For the study, the investigators combined COVID data with meteorological measurements taken from 121 countries.

They gathered COVID case counts and deaths from between January and August 2020, before vaccines were available, and then compared each day of data with an average estimated indoor humidity on that day.

For example, they reasoned that if outdoor temperatures fell below the typical human comfort range of 66 to 77 degrees Fahrenheit, folks would crank on the heat — and thus cause indoor humidity to fall.

As a result, they found that indoor relative humidity tended to drop below 40% during colder periods, and that COVID cases and deaths also spiked at those times.

The team also found a gradual rise of indoor humidity during tropical countries’ summer season reflected in a gradual increase in COVID deaths as humidity went past 60%.

COVID-19 cases and deaths tended to increase when a region’s average estimated indoor humidity was lower than 40% or higher than 60%, regardless of the time of year.

Nearly all regions had fewer COVID infections and deaths when average indoor humidity hovered in the “sweet spot” between 40% and 60%, the study authors said.

“We were very skeptical initially, especially as the COVID-19 data can be noisy and inconsistent,” said co-researcher Lydia Bourouiba, director of the MIT Fluid Dynamics of Disease Transmission Laboratory. “We thus were very thorough trying to poke holes in our own analysis,” she noted in an MIT news release.

Bourouiba said the team used a range of approaches to test the findings, including taking into account factors such as government intervention.

“Despite all our best efforts, we found that even when considering countries with very strong versus very weak COVID-19 mitigation policies, or wildly different outdoor conditions, indoor — rather than outdoor — relative humidity maintains an underlying strong and robust link with COVID-19 outcomes,” Bourouiba said.

The researchers aren’t sure why indoor humidity might have such an influence over COVID’s virulence, but follow-up studies have suggested that germs might survive longer in respiratory droplets in either very dry or very humid conditions.


Source: HealthDay

As Climate Warms, a China Planner Advocates “Sponge Cities”

Emily Wang Fujiyama wrote . . . . . . . . .

To cushion the impact of extreme weather due to climate change, a Chinese landscape architect has been making the case for China and other countries to create so-called “sponge cities.”

Yu Kongjian, who spoke to The Associated Press in Beijing, uses sweeping language to express his vision for cities that can withstand variable temperatures, drought and heavy rainfall. The challenges for implementing this vision at a time of ambitious economic development in China are multifold.

Yu criticizes much of Asia’s modern infrastructure for being built on ideas imported from Europe, which he says are ill-fitted to the monsoon climate over much of the Asian continent. He points to recent floods that have wreaked havoc in many Asian cities, which he says are caused by this architectural mismatch.

“There’s no resilience at all,” Yu says of the concrete and steel infrastructure of major cities, and of using pipes and channels to funnel away water. “Those are useless, they will fail and continue to fail.”

Instead, Yu proposes using natural resources, or “green infrastructure” to create water-resilient cities. It’s part of a global shift among landscape design and civil engineering professionals toward working more in concert with the natural environment. By creating large spaces to hold water in city centers — such as parks and ponds — stormwater can be retained on site, helping prevent floods, he says. Sponge infrastructure also, in theory, offers ways for water to seep down and recharge groundwater for times of drought.

“The idea of a sponge city is to recover, give water more space,” Yu said.

A turning point in China’s awareness of climate change and urban adaptation came a decade ago, Yu said. A devastating flood hit the capital city of Beijing in July 2012.

Beijing’s biggest downpour in 61 years overwhelmed drainage systems, swamped downtown underpasses and sent flash floods roiling through the city’s outskirts. At least 77 people died.

Yu at the time sent a letter to Beijing’s party secretary, Guo Jinlong, calling for a change in how the government approaches city infrastructure. He continued to send letters to high-ranking officials and top leadership, including China’s leader Xi Jinping.

At a government working conference the next year, China incorporated the idea of sponge cities as a national strategy, “giving full play to the absorption, storage and slow release of rainwater by ecological systems.”

In 2014, the central government issued a directive: Recycle 70% of rainwater runoff in 20% of urban areas by 2020, and in 80% of such areas by 2030.

The following year it launched 16 pilot sponge city projects, adding 14 more in 2016. Officals also said they would award 600 million yuan (83 million USD) each year for three years to municipal cities, 500 million to provincial capitals, and 400 million yuan to other cities.

The top-down mandate and subsidies spurred a boom in water-absorbing infrastructure, including in large cities including Beijing, Shanghai and Shenzhen.

Cities around the world are similarly trying to integrate “bioswales” along the sides of roads, protect remaining marsh areas to absorb water, and increase the capture of roof rainwater.

AN EXPERIMENT UNDERWAY

In China, one demonstration park is located in the northeast corner of the city of Nanchang, southern China. In mid October, engineers were putting finishing touches on a lush, picturesque 126-acre park designed to cushion the impact of both floods and droughts.

Formerly a coal ash dump site, the “Fish Tail” sponge park is built in a low-lying section of the city and intended to regulate water for surrounding neighborhoods and business districts. The fly ash, a byproduct of coal combustion, was mixed with soil to create mini-islands in the lake that allow water to permeate. Fang said the mixture, held in place by plant roots, prevents the ash from flowing into the water. Whether it prevents the release of toxic elements in the ash is an open question.

During dry periods, the water could be withdrawn, purified and used for plant irrigation.

Fang Yuan, an engineer at Yu’s design institute, Turenscape, said the park serves as “an ecological aquarium,” capable of retaining 1 million cubic meters of water during floods and means the water can be used, instead of just discharging it into the sewage system.

The park also serves as a habitat for plants and wildlife disrupted by extreme weather such as drought.

AN UNCERTAIN FUTURE

At times, the sponge city concept has been difficult to implement in China. Misallocation of funds, lack of expertise in sponge city planning, and other snags have doomed some projects.

In April, the Ministry of Housing and Urban-Rural Development announced some cities had “insufficient awareness, inaccurate understanding, and unsystematic implementation of sponge city construction.”

The notice also warned against using funds earmarked for sponge city construction for other general infrastructure projects, such as buildings and roads.

Those guidelines were issued after massive rainfall and catastrophic floods in the city of Zhengzhou killed 398 people last summer. Floodwater inundated a section of the city’s subway, trapping hundreds of commuters. Rescuers flocked to the scene, but 14 people died in the subway disaster.

Notably, Zhengzhou was one of the pilot sponge cities, with a planned investment of 53.58 billion yuan (US $7.4 billion). Some questioned whether sponge city projects work at all.

But an investigation by the State Council released in January, found that funds had been misspent. Only 32% of the 19.6 billion yuan that was invested went to what the government defined as sponge city concepts.

“Even at the critical moment when the whole country mobilized forces to support Zhengzhou’s rescue and disaster relief, they were still “building flower beds,” the State Council report said.

Yu acknowledges there is an oversight problem. “Many of the cities just use it as propaganda — just to get a lot of money from the central government,” but then invest the funds in other projects.

While problems implementing absorptive cities are worked out, China’s vulnerability to extreme weather is clear. A prolonged drought since July has dramatically shrunk China’s biggest freshwater lake, Poyang.

In the village of Tangtou, on the lake’s normally water-blessed northeast corner, residents scooped buckets of water from a village pond to tend their vegetables.

Since July, villagers say they’ve hardly seen any rainfall, let alone water in their corner of the lake.

“The whole lake was completely dry, and even the Yangtze River was dry,” said 73-year-old Duan Yunzhen, as he scattered pond water onto his crops.

“We planted rice, cotton, sesame, and sweet potato — they are all suffering from drought,” said 62-year-old Hong Zuhua.


Source : AP

Will We Ever . . . Live in City-sized Buildings?

Peter Ray Allison wrote . . . . . . . . .

The cities of science fiction are frequently portrayed as all-encompassing and self-contained structures, but how feasible is it to build a colossal city in a building?

Enclosed cities have become a narrative shorthand for futuristic settlements in science fiction. They are self-contained habitats, incorporating all essential infrastructure, including energy generation, food production, waste management and water.

The concept of an arcology – a portmanteau term combining architecture and ecology – was proposed by the architect Paolo Soleri in 1969, as he sought to combine construction with ecological philosophies. A year later, Soleri started work on Arcosanti, an experimental town in America, which demonstrated his concepts.

Soleri’s concepts inspired science fiction with a vision of futuristic cities: monolithic habitats where the population live and work without ever leaving the building. Cinematic examples include the massive high-rise buildings in Dredd (based on the comic book character Judge Dredd) and Skyscraper, although little detail is given on how they operate.

Science fiction, in turn, may have inspired some real-world variants. Saudi Arabia’s proposed The Line is pitched as a massive smart city which could house nine million people within a single 200m-wide (660ft) building, stretching 170km (105 miles) and 500m (1,650ft) high. The Line would be powered using solar energy and wind turbines, but would not be entirely self-sufficient, as food and other supplies would still be needed for the residents, and would have to be provided from external sources.

Some structures similar to arcologies already exist. For example, Antarctic research bases are relatively self-sufficient communities, mostly due to their remoteness. The surrounding environmental protections also mean that they need to be self-contained. The McMurdo Station provides housing for roughly 3,000 researchers and support staff. However, the station still requires significant supplies of food and fuel each year.

Other structures that are designed to be as self-contained and self-sufficient as possible include aircraft carriers, nuclear submarines and oil rigs. These have all of the living and work areas needed for the crew, albeit for short-term use. An aircraft carrier needs to be resupplied every few weeks, whilst a nuclear submarine can remain underwater for up to four months. However, neither of these are particularly pleasant places to live. Submarines in particular are cramped and smelly, sleeping quarters may be shared and the crew are prescribed vitamin D supplements due to lack of daylight.

But could we actually build an arcology? The size of such a structure would require massive foundations in order to support its weight. “You can build almost anything within reason,” says structural engineer Monika Anszperger of BSP Consulting. “The loadings would be massive, but nothing is unachievable. It will just cost more to build the foundations for it.”

The greater challenge caused by a building’s height is the effect of wind. Wind loading is of little concern for a typical house; but colossal towers, such as the Burj Khalifa in Dubai, need to consider the flow of wind and the resulting vortices. A vortex is the effect caused by wind hitting the surface of a building, creating an area of low pressure on the opposite side, then swirling around to fill it. It is this vortex action that causes tall buildings to sway during high winds.

The effects of swaying can range from drinks rippling to the structure collapsing. The Tacoma Narrows Bridge in Washington collapsed in 1940 due to strong winds inducing increasingly high frequency oscillations (rapid movements) on the bridge, to the point that the bridge tore itself to pieces. The effects of vortices can be mitigated through using a tuned mass damper (a device to reduce vibrations) to lessen the movement, as well as designing the structure to disrupt the wind flow.

“One way to mitigate vortexes is to change the shape of the building as it goes up,” says Adrian Smith, the architect of many large buildings, including Burj Khalifa. “If you don’t change the shape of the building, that vortex has an opportunity to build upon itself and create waves of movement. They synchronise with the structure of the building and cause progressive collapse.”

Therefore, rather than building an arcology as a shear-walled structure, as presented in Dredd, it is more likely that it would be built to disrupt windflow, such as by employing a stepped construction, like ancient MesoAmerican structures.

Another key challenge is energy generation. Renewable energy technologies, like solar panels and wind turbines, could be easily mounted on the exterior of an arcology, but are unlikely to provide a complete power solution on their own. As they would only be effective at certain times, back-up power generation and energy storage systems will be needed for when there is a shortfall.

Nuclear reactors are a possible alternative energy generation solution. Small modular reactors (SMRs), miniaturised factory-built versions of advanced nuclear reactors, are compact and efficient energy sources. SMRs claim some benefits over large reactors, in terms of enhanced safety and prevention of proliferation of nuclear materials. However, as with all fission reactors, the processing and storage of nuclear waste is a challenge. Alternatively, fusion reactors would be safer and provide cleaner forms of energy, however current designs are neither compact (one, Iter, is expected to weigh 23,000 tons) nor financially viable, as none have yet produced more energy than they use.

Food production also needs to be considered. Conventional farming would be impractical within a building. Vertical hydroponic farms could be used, which would also provide a natural form of air recycling. However, the necessary lighting would increase energy demand and space constraints could make it difficult to produce sufficient food.

The arcology portrayed in Paolo Bacigalupi’s novel Water Knife used a series of filtration ponds to recycle water, which is plausible. However, losses are inevitable in any recycling system. The International Space Station (ISS) recycles approximately 3.6 gallons (17.3 litres) of water every day, including urine and perspiration, but still requires regular supplies of fresh water every few months.

Not everyone sees a future for high-rise buildings. In 2021, China banned new buildings over 500m (1,650ft) tall and imposed severe restrictions on buildings over 250m (825ft).

Nonetheless, the Earth’s growing population needs to be accommodated. Continually expanding cities horizontally, through building on new land, is not sustainable indefinitely. This bolsters the argument for growing upwards, creating vertical cities. “Cities are expanding massively, going from one to 10 million,” says Antony Wood, director of Tall Buildings and Vertical Urbanism at the Illinois Institute of Technology and president of the Council on Tall Buildings and Urban Habitat. “They can’t go horizontal, because it’s unsustainable, for land consumption and the energy taken to build and operate the horizontal city. It’s going to go vertical.” (Read more about whether we are running out of space.)

Instead of independent tower blocks, buildings could become interconnected with land bridges, creating green spaces between them. However, building ever upwards with a network of land bridges risks putting the lower levels into shadow, making the higher levels ever more desirable, thus leading to a structured hierarchal system.

“I do see cities expanding vertically near areas of transit and I definitely see them expanding horizontally as well,” says Smith.

As the effects of climate change become ever more apparent, the materials cities are built from could change. Carbon emissions from the cement industry outweigh those from the aviation sector. One alternative construction material could be mass timber: an engineered product created from layered panels of wood that are bound together. “The amount of energy to produce mass timber is a fraction of what it would be to produce the same materials in steel or concrete,” says Wood. “While it’s producing itself, it’s sequestering carbon out of the atmosphere.”

Although building an arcology is theoretically possible, at least from a structural perspective, it would require inventive engineering to ensure the necessary energy generation, food production and waste reclamation systems are sustainable. Critics say it is difficult to see how arcologies could be made economically viable in the near future. There is also the argument that permanently living within an enclosed area would not be pleasant, although it is comforting to know it is possible, should an apocalyptic event make the outside world unhabitable.

“I would never say something cannot be built,” concludes Anszperger. “It can be built, but there needs to be a vision and a need for it.”


Source : BBC

Can We Save the Planet and Still Eat Meat?

Bob Holmes wrote . . . . . . . . .

As governments drag their feet in responding to climate change, many concerned people are looking for actions they can take as individuals—and eating less meat is an obvious place to start. Livestock today account for about 14.5 percent of global greenhouse gas emissions, more than all the world’s cars and trucks combined.

Those numbers are daunting already, but the situation could grow worse: Our appetite for meat is increasing. The United Nations forecasts that the world will be eating 14 percent more of it by 2030, especially as middle-income countries get wealthier. That means more demand for pasture and feed crops, more deforestation, and more climate problems. For people alarmed about climate change, giving up meat altogether can seem like the only option.

But is it? A growing body of research suggests that the world could, in fact, raise a modest amount of beef, pork, chicken, and other meat, so that anyone who wants could eat a modest portion of meat a few times a week—and do so sustainably. Indeed, it turns out that a world with some animal agriculture in it likely would have a smaller environmental footprint than an entirely vegan world. The catch is that hitting the environmental sweet spot would require big changes in the way we raise livestock—and, for most of us in the wealthy West, a diet with considerably less meat than we eat today.

“The future that sounds sustainable to me is one where we have livestock, but it’s a very different scale,” says Nicole Tichenor Blackstone, a food systems sustainability researcher at Tufts University in Boston. “I think the livestock industry’s going to have to look different.”

One big reason for meat’s outsized environmental impact is that it’s more efficient for people to eat plants directly than to feed them to livestock. Chickens need almost 2 pounds of feed to produce each pound of weight gain, pigs need 3 to 5 pounds, and cattle need 6 to 10—and a lot of that weight gain is bones, skin, and guts, not meat. As a result, about 40 percent of the world’s arable land is now used to grow animal feed, with all the attendant environmental costs related to factors such as deforestation, water use, fertilizer runoff, pesticides, and fossil fuel use.

But it’s not inevitable that livestock compete with people for crops. Ruminants—that is, grazing animals with multiple stomachs, like cattle, sheep, and goats—can digest the cellulose in grass, straw, and other fibrous plant material that humans can’t eat, converting it into animal protein that we can. And two-thirds of the world’s agricultural lands are grazing lands, many of which are too steep, arid, or marginal to be suitable for crops. “That land cannot be used for any other food-growing purpose other than the use of ruminant livestock,” says Frank Mitloehner, an animal scientist at the University of California, Davis.

Of course, those grazing lands could revert to natural forest or grassland vegetation, taking up atmospheric carbon in the process. This carbon-capturing regrowth could be a major contributor to global climate-mitigation strategies aimed at net-zero greenhouse gas emissions, researchers say. But that’s not necessarily incompatible with moderate levels of grazing. For example, some research suggests that replacing croplands with well-managed grazing lands in the southeastern U.S. captures far more carbon from the atmosphere.

Livestock can also use crop wastes such as the bran and germ left over when wheat is milled to white flour, or the soy meal left over after pressing the beans for oil. That’s a big reason why 20 percent of the U.S. dairy herd is in California’s Central Valley, where cows feed partly on wastes from fruits, nuts, and other specialty crops, Mitloehner says. Even pigs and chickens, which can’t digest cellulose, could be fed on other wastes such as fallen fruit, discarded food scraps, and insects, which most people wouldn’t eat.

The upshot is that a world entirely without meat would require about one-third more cropland—and therefore, more energy-intensive fertilizer, pesticides, and tractor fuel—to feed everyone, says Hannah van Zanten, a sustainable food systems researcher at Wageningen University in the Netherlands. But only if we’re talking about meat raised the right way, in the right amounts.

Livestock also bring other benefits. Meat provides balanced protein and other nutrients such as iron and vitamin B12 that are more difficult to get from a vegan diet, especially for poorer people who can’t always afford a variety of fresh vegetables and other nutritious foods, says Matin Qaim, an agricultural economist at the University of Bonn, Germany, who co-authored a look at the sustainability of meat consumption in the 2022 Annual Review of Resource Economics. Livestock, he notes, are the main source of wealth for many otherwise poor people in traditional pastoral cultures. And on small, mixed farms, animals that graze widely and then deposit their manure in the farmyard can help to concentrate nutrients for use as fertilizer in the family’s garden.

Moreover, many of the world’s natural grasslands have evolved in the presence of grazers, which play a key role in ecosystem function. Where those native grazers no longer dominate—think of the vanished bison from the American prairies, for example—domestic livestock can fill the same role. “Grasslands are disturbance-dependent,” says Sasha Gennet, who heads the sustainable grazing lands program for the Nature Conservancy. “Most of these systems evolved and adapted with grazing animals and fire. They can benefit from good livestock management practices. If you’re doing it right, and you’re doing it in the right places, you can have good outcomes for conservation.”

For all these reasons, some experts say, the world is better off with some meat and dairy than it would be with none at all—though clearly, a sustainable livestock system would have to be much different, and smaller, than the one we have today. But suppose we did it right? How much meat could the world eat sustainably? The answer, most studies suggest, may be enough to give meat-eaters some hope.

Interdisciplinary researcher Vaclav Smil of the University of Manitoba got the ball rolling in 2013 with a back-of-the-envelope calculation published in his book, Should We Eat Meat? Let’s assume, he reasoned, that we stop clearing forest for new pastureland, let 25 percent of existing pastures revert to forest or other natural vegetation, and feed livestock as much as possible on forage, crop residues, and other leftovers. After making those concessions to sustainability, Smil’s best guesstimate was that this “rational” meat production could yield about two-thirds as much meat as the world was producing at the time. Subsequent studies suggest that the real number might be a bit lower, but still enough to promise a significant place for meat on the world’s plate, even as the population continues to grow.

If so, there are several surprising implications. For one thing, the total amount of meat or dairy that could be produced in this way depends strongly on what else is on people’s plates, says van Zanten. If people eat a healthy, whole-grain diet, for example, they leave fewer milling residues than they would on a diet heavy in refined grains—so a world full of healthy eaters can support fewer livestock on its leftovers. And little choices matter a lot: If people get most of their cooking oil from canola, for example, they leave less nutritious meal for feed after pressing out the oil than if they get their oil from soy.

A second surprise is the nature of the meat itself. Sustainability experts typically encourage people to eat less beef and more pork and chicken, because the latter are more efficient at converting feed into animal protein. But in the “livestock on leftovers” scenario, the amount of pork and chicken that can be raised is limited by the availability of milling residues, food scraps, and other food wastes. In contrast, cattle can graze on pasture, which shifts the livestock balance back somewhat toward beef, mutton, and dairy products.

Much would have to change to make such a world possible, van Zanten notes. To maximize the flow of food wastes to pigs and chickens, for example, cities would need systems for collecting household wastes, sterilizing them, and processing them for feed. Some Asian countries are well ahead on this already. “They have this whole infrastructure ready,” van Zanten says. “In Europe, we don’t.” And much of our current animal agriculture, based on grain-fed livestock in feedlots, would have to be abandoned, causing significant economic disruption.

Moreover, people in wealthy countries would have to get used to eating less meat than they currently do. If no human-edible crops were fed to livestock, van Zanten and her colleagues calculated, the world could only produce enough meat and dairy for everyone to eat around 20 grams of animal protein per day, enough for a three-ounce piece of meat or cheese (about the size of a deck of cards) each day. By comparison, the average North American now chows down on about 70 grams of animal protein a day—well above their protein requirement—and the average European on 51.

That’s a hefty reduction in meat—but it would bring significant environmental benefits. Because livestock would no longer eat feed crops, the world would need about a quarter less cropland than it uses today. That surplus cropland could be allowed to regrow into forest or other natural habitat, benefitting both biodiversity and carbon balance.

There’s another dimension to meat’s sustainability, though. The gut microbes that let grazing animals digest grasses and other human-inedible forage release methane in the process—and methane is a potent greenhouse gas. Indeed, methane from ruminants accounts for about 40 percent of all livestock-related greenhouse gas emissions. Animal scientists are working on ways to reduce the amount of methane produced by grazers. At present, however, it remains a serious problem.

Paradoxically, raising cattle on grass—better for other dimensions of sustainability—makes this problem worse, because grass-fed cattle grow more slowly. Grass-fed Brazilian cattle, for example, take three to four years to reach slaughter weight, compared with 18 months for U.S. cattle finished on grain in feedlots. And that’s not all: Because the grain-fed animals eat less roughage, their microbes also produce less methane each day. As a result, grass-fed beef—often viewed as the greener option—actually emits more methane, says Jason Clay, senior vice president of markets for the World Wildlife Fund-U.S.

Even so, raising livestock on leftovers and marginal grazing lands not suitable for crops eliminates the need to grow feed crops, with all their associated emissions, and there will be fewer livestock overall. As a result, greenhouse gas emissions may end up lower than today. For Europe, for example, van Zanten and her colleagues compared expected emissions from livestock raised on leftovers and marginal lands against those from animals fed a conventional grain-based diet. Livestock on leftovers would produce up to 31 percent less greenhouse gas emissions than the conventional approach, they calculated.

Some sustainability experts also argue that as long as grazing herds aren’t increasing, methane may be less of a worry than previously thought. Molecule for molecule, methane contributes about 80 times more warming than carbon dioxide does in the short term. However, CO₂ persists in the atmosphere for centuries, so newly emitted CO₂ always makes the climate crisis worse by adding to the stock of CO₂ in the atmosphere. In contrast, methane lasts only a decade or so in the atmosphere. If livestock levels remain constant over the span of decades, then the rate at which old methane washes out of the atmosphere will be about equal to the rate at which new methane is emitted, so there would be no additional burden on climate, says Qaim.

But with climate experts warning that the world may be fast approaching a climate tipping point, some experts say there’s good reason to reduce meat consumption well below what’s sustainable. Completely eliminating livestock, for example, would allow some of the land now devoted to feed crops and pastures to revert to native vegetation. Over 25 to 30 years of regrowth, this would tie up enough atmospheric CO₂ to completely offset a decade’s worth of global fossil fuel emissions, Matthew Hayek, an environmental scientist at New York University, and his colleagues reported in 2020. Add to that the rapid reduction in methane no longer emitted by livestock, and the gains become even more attractive.

“We need to be moving in the opposite direction than we are now,” says Hayek. “The things that are going to do that are aggressive, experimental, bold policies—not ones that try to marginally reduce meat consumption by 20 or even 50 percent.”


Source: Slate

1 Million Square Feet of L.A. Roads Are Being Covered with Solar-reflective Paint

Elissaveta M. Brandon wrote . . . . . . . . .

It’s no secret by now that cities run hotter than the countryside: Fewer trees mean less shade, and concentrated human activity generates heat, which hard surfaces like pavement and parking lots absorb.

To combat the so-called urban heat island effect, some cities have been retrofitting public buildings into climate shelters, while others have been planting thousands of trees. One Los Angeles neighborhood is turning to solar-reflective paint.

The team behind the GAF Cool Community Project has just finished painting a whopping 1 million square feet of roads, playgrounds, and parking lots in Pacoima. The paint comes with special additives that reflect infrared light, meaning painted pavement ends up absorbing less heat.

Most of the surfaces have been painted a light shade of gray, but a local artist was commissioned to design a series of colorful murals on a basketball court, a school playground, and a parking lot.

The initiative comes on the heels of a series of dangerous heat waves in the U.S. affecting more than 16 million Americans. Painting streets may not be the silver bullet that fixes the urban heat island effect, but in Pacoima, it has already cooled the surface by about 10 to 12 degrees, highlighting the potential for a simple yet effective upgrade.

The project will now investigate how much the cooler surfaces will bring the neighborhood temperature down as a whole.

It’s not the first time that cities have turned to paint to reduce heat (though typically, that paint is white, like in New York City, where more than 10 million square feet of rooftops have been painted in the past 10 years).
The Pacoima project was led by roofing giant GAF as a philanthropic initiative, which has already worked with the City of Los Angeles’s Cool Streets Project and the L.A. Unified School District to paint almost 90 playgrounds and school parking lots across the city.

The idea is to see if a larger-scale initiative can have even greater cooling effects. For now, the data is anecdotal: When they measured in the middle of the day, the team noticed a 30-degree difference compared to untreated pavement. But over the next two years, the company will gather weekly data on the surface temperature throughout the neighborhood—and if the initiative proves successful, they’re hoping to replicate the model across other neighborhoods.

“The ultimate goal is not just to lower the ambient temperature of the community but to see how it impacts the livelihoods of people in the community,” says Jeff Terry, vice president of corporate social responsibility and sustainability at GAF.

The concept relies on a special kind of coating called Invisible Shade. (It’s produced by StreetBond, a GAF company.) Eliot Wall, StreetBond’s general manager, explains that Invisible Shade comes with additives that don’t just reflect visible light (like conventional white paint) but also infrared light (IR). (Sunlight consists of both types, but IR light accounts for most of the heat.)

“There’s a chance for a multiplier effect given those additives,” Wall says.

The Invisible Shade collection comes in 14 colors, but custom colors are also possible, like the range of shades developed for a “warming stripes” mural depicting the annual temperature change in L.A. County from 1895 to 2021.
“We created a visual connection,” Wall says. “And in doing so, created a space where people can spend more time.”


Source : Fast Company

The Search for an Air Conditioner That Doesn’t Destroy the Planet

Rebecca Heilweil wrote . . . . . . . . .

A growing number of startups are tinkering with the science behind cooling. Hildegarde/Getty Images
Amid a growing number of heat waves, air conditioners have become a lifeline. Because these appliances are critical to keeping people cool — and protecting them from dangerously hot weather — the International Energy Agency (IEA) estimates that there may be more than 5 billion air conditioners across the planet by 2050. The problem is that while air conditioners do keep people safe, they’re also a major contributor to climate change.

So why not rethink the AC entirely?

The basic science of air conditioners hasn’t changed much since they were first invented about a century ago, but these appliances have become a bigger and bigger threat to life on Earth. Most modern air conditioners consume a massive amount of energy, strain the electrical grid during sweltering summer days, and use harmful chemicals, called refrigerants, that trap heat in the atmosphere. That’s why, along with a vast number of other structural changes the world will need to make to fight climate change, some experts say it’s time to change how we cool our homes.

“We need to design our buildings in a way that consumes less energy. We need to insulate them better. We need to ventilate them better,” explained Ankit Kalanki, a manager at Third Derivative, a climate tech accelerator co-founded by the sustainability research organization RMI. “These strategies are very important. We can reduce the air conditioning demand in the first place, but we cannot eliminate that.”

The race to redesign the AC is already on. The IEA predicts that within the next three decades, two-thirds of the world’s homes could have air conditioners. About half of these units will be installed in just three countries: India, China, and Indonesia. The extent to which these new air conditioners will exacerbate climate change hinges on replacing the cooling tech we currently use with something better. Right now, ideas range from retrofitting our windows to more far-out concepts, like rooftop panels that reflect sunlight and emit heat into space. To succeed, however, the world will need to boost the efficiency of the appliances we already have — as quickly as possible — and invest in new tech that could avoid some of AC’s primary problems.

The AC’s noxious environmental impact stems from its core technology: vapor compression. This tech involves several components, but it generally works by converting a refrigerant that’s stored inside an AC from a liquid to a gas, which allows it to absorb heat, removing it from a room. Vapor compression uses an immense amount of electricity on the hottest days, and there are growing concerns that the technology might eventually overwhelm the grid’s capacity to provide power. And hydrofluorocarbons, the chemical refrigerants that many ACs use to soak up heat, are greenhouse gases that trap lots of heat in our atmosphere when leaked into the air. The challenge is that, for now, vapor compression ACs are still a critical tool during deadly heat waves, especially for high-risk populations, young children, older adults, and people with certain health conditions.

Technology to build cleaner, more efficient air conditioners does exist. Two major AC manufacturers, Daikin and Gree Electric Appliances, shared the top award at last year’s Global Cooling Prize, an international competition focused on designing climate-friendly AC tech. Both companies created ACs with higher internal performance that used less environmentally damaging refrigerants; the new units could reduce their impact on the climate by five times. These models aren’t yet on the market — Gree plans to start selling its prototype in 2025, and Daikin told Recode that it hopes to use the new technology in future products — but the IEA estimates that using more efficient ACs could cut cooling’s environmental impact by half.

Another strategy is to double down on heat pumps, which are air conditioners that also work in reverse, using vapor compression to absorb and move heat into a home, instead of releasing it outside. Heat pumps usually cost several thousand dollars, though the Inflation Reduction Act includes a proposal for a significant heat pump rebate, and President Joe Biden has invoked the Defense Production Act to ramp up production. Experts have argued installing heat pumps is critical to another important climate goal: transitioning away from fossil fuel-powered furnaces, which are an even bigger source of emissions than cooling. The holy grail of HVAC would be a heat pump that could provide both heating and cooling but isn’t dependent on vapor compression.

“Heat pumps are a critical technology in reducing our energy consumption, enhancing grid reliability and the utilization of renewable power, reducing emissions, reducing our reliance on foreign sources of energy, and lowering utility bills for US families and businesses,” Antonio Bouza, a technology manager at the Department of Energy, told Recode. The next step, he said, is reducing emissions even further by designing heat pumps that don’t rely on refrigerants, as current vapor compression systems do.

Another challenge, though, is that heat pumps are not the easiest appliance to install, especially for renters, who don’t necessarily have the money or ability to invest in bulky HVAC systems. To address this problem, a company called Gradient has designed a heat pump that easily slides over a windowsill — it doesn’t block light — and currently uses a refrigerant called R32, which is supposed to have a (comparatively) low global warming potential. Gradient recently won a contract to install its units in New York City public housing.

A fleet of new companies want to make even bigger changes to how we cool our homes. One of these startups is Blue Frontier, which is backed by Bill Gates’s investment fund, Breakthrough Energy Ventures, and plans to start selling its futuristic AC units in 2025. The company’s technology uses a specialized salt solution that can release water into the air — or draw it out — which allows the AC to control its temperature. This approach, Blue Frontier claims, can save up to 90 percent of the energy used by a traditional AC and avoids draining electricity from the grid during peak hours.

“By eliminating air conditioning that’s a problem for the grid, it allows the grid to actually reduce the costs of power production [and] utilize renewable energies in a more effective manner,” Daniel Betts, the CEO of the company, told Recode. “So not only do we save energy, but we are saving energy at the moments that are most critical.”

Scientists and startups are playing with other concepts, too. One path, which the company Transaera is taking, is to develop new materials that efficiently soak up moisture from the air, almost like a sponge, so that air conditioners can work more efficiently. A similar concept is to take advantage of solid-state technology. This idea would use solid materials to absorb heat, and some research on it has support from the US Department of Energy. The British firm Barocal is developing a type of plastic crystal that could do this and also help control temperature. One company, Phononic, has developed a solid-state core that could be integrated into existing HVAC systems. The company says its first commercial installation will be next year.

While many of these technological breakthroughs are promising, the movement to revolutionize air conditioning still faces some major challenges. Right now, AC manufacturers primarily focus on meeting minimum performance standards, rather than competing for higher levels of efficiency. Consumers also tend to buy air conditioners based on their sticker price, not an AC’s overall impact on their energy bills. And even though there are a growing number of AC-focused startups, the industry is still dominated by a small handful of large companies, all of which primarily focus on far-from-ideal vapor compression tech.

“We don’t install more efficient technologies unless we really need to, or it’s mandated by a government or another organization,” said Eli Goldstein, the co-founder and CEO of SkyCool, a startup developing tech that could be used to send heat from buildings and ACs into space. “Ultimately, the key is going to be dollar investments from both private and public enterprises to deploy the technologies.”

Other changes, like better insulating our homes and installing batteries throughout the grid, are still critical in the fight against climate change. However, all signs indicate that humans will continue to buy air conditioners, not just to feel comfortable but to survive increasingly devastating weather brought on by climate change. This is especially true as temperatures and incomes rise in some of the world’s largest countries and fastest-growing economies. In India alone, demand for cooling tech was already growing between 15 and 20 percent every year, as of 2020.

This surging demand creates a promising, but incredibly risky, situation. There’s the possibility that the growing need for cooling spurs a race to build the best AC technology and, ideally, tech that could also displace fossil fuel-based heating. But if better, more affordable AC doesn’t come to market fast enough — especially for the vast number of people in developing countries who will buy these appliances in the coming decades — significantly worse air conditioners will take their place, warming the planet even faster.


Source : Vox

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