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Category Archives: Climate

Chart: The Last 8 Years Have Been the Warmest on Record

Source : Statista

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.


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.


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

Chart: When Can You Expect El Niño and La Niña?

Source : Statista

Infographic: Countries With the Highest Flood Risk

See large image . . . . . .

Source : Visual Capitalist

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


作者: 何國俊 . . . . . . . . .



為了應對極端氣候勢將帶來的超額死亡,政策制定者有兩大核心工具可用:一、減緩氣候變化政策(climate change mitigation policy),即通過降低能源的生產和消耗來減少溫室氣體排放。二、適應氣候變化政策(climate change adaptation policy),比如天氣寒冷之際,提供廉價取暖能源;夏季時則在公共場所和家居進一步普及空調等。2016年,《政治經濟學期刊》(Journal of Political Economy)的一篇文章估計,近半個多世紀以來,隨着空調的普及,美國人死於酷熱的風險下降了75%。







在搜集和分析了日本在2008至2015年間各地區的死亡、天氣、節能目標等資料後,筆者與柏克萊加州大學的合作者Takanao Tanaka在研究中發現,節能政策會加劇極端溫度對死亡率的影響:在節能目標較高的地區,更多人死於極端高溫或低溫。由於日本節能政策主要強調要在夏季節約用電,高溫帶來的死亡風險上升最為明顯。具體來說,我們的測算表明,日本大規模的節能政策造成與高溫相關的死亡風險增加了約3倍,導致每年超過7700人超額死亡。






Source : HKU

In Pictures: Central China Dongting Lake Is Drying Up

Water channels in Dongting Lake in Junshan district, Yueyang in Central China’s Hunan province, dried up on Sunday. Since July, China’s second-largest freshwater lake has shrunk dramatically due to a combination of extreme heat and low rainfall

Monitoring data from the National Satellite Meteorological Center shows that the water area of Dongting Lake was about 546 square kilometers on Aug. 21, a decrease of about 62% compared with August 10 years ago.

The drought has turned part of Dongting Lake into grassland.

Birds are foraging near the dried-up bed of Dongting Lake.

A man rides his motorcycle on the lakebed.

The water level at Dongting Lake’s Chenglingji hydrological station fell to 21.75 meters at 8 a.m. Monday, the lowest record for August in 50 years.

The sediment-rich water of Dongting Lake runs into the Yangtze River on Monday in Yueyang.

Source : Caixin

Infographic: What Droughts Have Revealed

Source : Statista

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

Infographic: 5 Things to Know About Europe’s Scorching Heatwave

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Source : Visual Capitalist