05 Nov 2013:
Beijing To Limit New Cars
By 40 Percent in Anti-Pollution Drive
In an effort to reduce severe air pollution in the Chinese capital, Beijing will limit by 40 percent the number of new cars sold annually for the next four years, cutting license plate allocations from 240,000 to 150,000 each
Chang'an avenue in Beijing
year. The cap, which should also help ease the capital's worsening traffic congestion, means Beijing will license only 600,000 new cars between 2014 and 2017 — fewer than in 2010 alone, Reuters reports
. By 2017, 40 percent of those licenses, which drivers vie for in auctions and lotteries, will be reserved for hybrid and electric cars. New car sales in China are currently capped in four cities — Beijing, Shanghai, Guangzhou, and Guiyang — and the government plans to limit sales in eight additional cities, the China Association of Automobile Manufacturers said.
30 Oct 2013:
Low on Natural Gas, China
Cities Will Face Choking Air Pollution
In a push to curb air pollution, China has been urging its cities to rely more heavily on natural gas and less on coal. But a shortage of natural gas is threatening that goal, as urban populations boom and domestic gas production lags, Reuters reports
. Chinese officials have said that to reduce air pollution the most densely populated parts of Beijing should use only gas heat, which limits the supply of natural gas for smaller cities and forces those cities to rely on coal. Pollution levels in Chinese cities commonly exceed World Health Organization guidelines by 40 to 50 times. The problem is most pronounced in northern China, where air pollution from burning coal has already shortened life expectancy by 5.5 years compared to the southern part of the country. China's natural gas shortage is expected to be 10 percent higher this year than last year, since more users have switched from coal. Authorities are rationing natural gas and prioritizing its use for homes and transportation, but experts don't expect the shortage to subside anytime soon.
28 Oct 2013:
Underground Heat From
Cities Could Help Power Them, Study Says
The heat generated by urban areas and their buildings, factories, sewers, and transportation systems could be used to power those cities, according to a new study by German and Swiss researchers
. Thermal energy produced by the so-called "urban heat island effect" warms shallow aquifers lying below cities, and geothermal and groundwater heat pumps could tap into those warm reservoirs to heat and cool buildings, the scientists say. In the southwest German city of Karlsruhe, the researchers found that the city of 300,000 generated 1 petajoule of heat per year — enough to heat 18,000 households. Karlsruhe's underground heat production increased by about 10 percent over the past three decades, the team reported in Environmental Science and Technology
. The biggest contributors to the city's underground heat flux were its densely populated residential areas and surface temperature increases associated with paving. Sewage pipes, underground district heating networks, and thermal waste water discharges also contribute to warming shallow aquifers, the study found.
Above a Whole Foods Market,
A Greenhouse Grows in Brooklyn
By the end of this year, a neighborhood in Brooklyn, New York, will witness the completion of a cutting-edge partnership in urban agriculture and retail — a 20,000-square-foot rooftop greenhouse built on a Whole Foods
Gotham Greens' existing greenhouse in Brooklyn.
supermarket. Atop this newly constructed store in Gowanus, Brooklyn, Gotham Greens
, a New York company that grows greenhouse vegetables, plans to grow leafy vegetables and tomatoes, which will be sold at the store below and at other Whole Food markets. Scheduled for completion in December, Gotham Greens says the new facility will be capable of producing 150 tons of produce each year, a significant increase over the capacity of the company’s existing 100-ton-per-year solar-powered rooftop greenhouse in nearby Greenpoint, Brooklyn. Read more.
15 Oct 2013:
Nine in 10 Europeans in Cities
Breathe Dangerous, Polluted Air, Study Says
More than 90 percent of Europeans living in cities are exposed to harmful levels of air pollutants, according to a new assessment
from the European Environment Agency. Concentrations of ground-level ozone, or smog,
pose a danger to 97 percent of city populations, and levels of fine particulate matter (particles with a diameter less than 2.5 microns, known as PM2.5) exceed European standards for 91 to 96 percent of city-dwellers — and European standards for both pollutants exceed World Health Organization
recommendations. A new study of European mothers linked higher PM2.5 exposure
to lower birth weight, a standard indicator of fetal development. Eastern European countries have the highest levels of PM2.5, whereas ground-level ozone is worst in northern Italy. Although emissions of most air pollutants have steadily declined over the past 10 years — lead and carbon monoxide levels, for example, now meet international standards in most areas — emissions haven't fallen as much as predicted.
11 Sep 2013:
Arsenic in Vietnam Groundwater
Slowly Moving Toward Hanoi, Study Says
As the population and water needs of Hanoi mushroom, the capital city of Vietnam is slowly drawing poisonous arsenic into the aquifer that supplies its drinking water, say researchers from the U.S. and Vietnam
. Water contaminated with arsenic has moved more than a mile
The Red River
closer to the aquifer over the last 40 to 60 years, the researchers report in Nature
, due to the city's increasing water demand; municipal pumping in Hanoi doubled between 2000 and 2010. The good news, says lead researcher Alexander van Geen of Columbia University's Lamont-Doherty Earth Observatory, is the contaminated groundwater "is not moving as fast as we had feared it might.” This will give Hanoi officials time, perhaps decades, to determine how to best deal with the problem. The study also determined why arsenic is leaching into the groundwater: As water containing arsenic mixes with high levels of organic carbon from the Red River and other surrounding aquifers, the chemistry changes and arsenic dissolves in the water.
19 Aug 2013:
Future Flood Losses
Could Increase Ten Times by 2050
The rapid growth of the world’s coastal cities, coupled with sea level rise and land subsidence, could mean that flood losses in major metropolitan areas could rise from
$6 billion in 2005 to more than $60 billion in 2050
, according to a new study. Reporting in the journal Nature Climate Change
, researchers said sea level increases of 8 to 16 inches by 2050 could cause $60 billion to $63 billion in damages in 136 of the world’s coastal cities.
That figure assumes the cities will undertake some flood control measures. Cities whose infrastructure and buildings are now most at risk — including New York; New Orleans; Miami; Guangzhou, China; and Osaka, Japan — will be joined in four decades by other rapidly growing cities,
such as Ho Chi Minh City in Vietnam and Abidjan, Ivory Coast.
Interview: Scientists, Aid Experts
Prepare for a Warmer Future
Harvard University recently sponsored a conference that brought together two groups — climate scientists and humanitarian relief workers — that will undoubtedly be collaborating more closely in the future
as natural disasters intensify in a warming world. The woman who was instrumental in opening a dialogue between these two factions was Jennifer Leaning
, the director of the FXB Center for Health and Human Rights
at the Harvard School of Public Health. In an interview with Yale Environment 360
, Leaning says the meeting underscored the huge challenges the aid community will face in a world of more extreme weather and rising seas. But at this point, she says, climate science cannot offer the specific predictions about timing or locations of climate upheaval that the aid community is seeking. “The humanitarians found that the questions they were asking were not the ones that the climate scientists were prepared to answer,” says Leaning. Read the interview
13 Aug 2013:
Too Many Urban Beehives
May Do More Harm Than Good, Experts Say
A surge in urban beekeeping may be doing more harm than good to honeybee populations
, according to UK scientists. As the number of rooftop hives increases in cities worldwide
— including London, where there are
A Berlin beekeeper
now 10 hives per square kilometer — two researchers from the University of Sussex warn that too many hives can be detrimental. Writing in The Biologist
, the magazine of the Society of Biology, they suggest that inexperienced beekeepers can create conditions in which there isn’t enough food for their insects. “If there are too many colonies in an area, then the food supply will be insufficient,” Francis Ratnieks, a professor at the university’s Laboratory of Apiculture and Social Insects, told the BBC. “This will mean that colonies do not thrive, and may also affect other species that also visit flowers.”
09 Aug 2013:
Mapping of Monarch Butterfly
Migration Yields Clues About Decline
A comprehensive mapping of the North American migration patterns of the iconic monarch butterfly
could help preserve a species threatened by loss of habitat and food sources
, a team of international
A monarch butterfly
researchers says. In a study conducted across 17 U.S. states and two Canadian provinces, from southern Texas to Alberta, biologists from Canada, the U.S., and Australia tracked the northward migration of the monarchs, documenting five generations in a single breeding season. By analyzing a chemical signature found on the adult butterflies’ wings that reveals their specific birthplace, scientists were able to track the different generations of butterflies as they migrated north to the U.S. Midwest, from which many butterflies then traveled to Alberta. According to Tyler Flockhart, a Ph. D. student at the University of Guelph in Canada and lead author of the study published in the Proceedings of the Royal Society B
, the decline in milkweed and a surge in genetically modified crops might be affecting monarch survival.
08 Aug 2013:
Conventional Hybrids Better
For Climate than EVs in Most U.S. States
Conventional gas-powered hybrid vehicles are still better for the climate than all-electric cars in most U.S. states, in part because these states still rely heavily on fossil fuels to produce electricity, according to a new report
. In 39 states, high-efficiency hybrids, such as the
Toyota Prius, produce fewer carbon emissions during their lifecycle than the least-polluting electric cars, an analysis by Climate Central found. Although an increased reliance on cleaner energy sources in some parts of the country doubled the number of states (32) where driving electric cars would be more environmentally friendly, that advantage disappeared when analysts also considered the high emissions associated with building the batteries and other components for the EVs. In 11 states, the best all-electric cars are better for the environment than gas-powered hybrids, even when manufacturing is taken into account. In 26 states, plug-in hybrid cars are the most climate-friendly vehicles, the analysis found.
11 Jul 2013:
‘Peak Oil’ Concerns Overstated
As Demand Will Fall, Study Predicts
Researchers say concerns that humanity will inevitably reach a moment of “peak oil,” which would be followed by a crippling decline in supplies, are unwarranted
because global demand for oil is approaching its own peak
. Writing in the journal Environmental Science & Technology
, researchers from Stanford University and the University of California-Santa Cruz (UCSC) say that dire projections of peak oil mistakenly assume that an increasingly wealthy planet will continue to rely heavily on oil. On the contrary, they say, the link between economic growth and oil is breaking down as a result of increased energy efficiency, lower prices for alternative fuel sources, urbanization, and limits on consumption by the wealthy. While the researchers project surging global demand for airline travel and various forms of freight transportation, there will be less reliance on oil, with conventional oil demand declining after 2035.
13 Jun 2013:
Population Could Be 11 Billion
By End of the Century, UN Report Says
United Nations report
projects that the world population could reach nearly 11 billion by 2100
, about 8 percent more than predicted just two years ago. The projected increase largely stems from the fact that the fertility rate in Africa has declined more slowly than expected, with demographers now forecasting that the number of people on the continent could nearly quadruple this century, from from about 1.1 billion today to about 4.2 billion. “The fertility decline in Africa has slowed down or stalled to a larger extent than we previously predicted, and as a result the African population will go up,” said Adrian Raftery, a professor of statistics and sociology at the University of Washington, who helped develop the statistical method used in the report. The total world population passed 7 billion in 2011. According to the new report, 8 of the top 10 increases in national populations by 2100 will occur in Africa, led by Nigeria, where the number of people is expected to jump from 184 million to 914 million.
02 Apr 2013:
Air Pollution Linked to
1.2 Million Chinese Deaths in 2010
Air pollution contributed to the premature deaths of more than 1.2 million people in China in 2010, or about 40 percent of early deaths worldwide caused by dirty air, according to a newly released analysis. The findings, based on data from a study on the distribution and causes of death globally, categorized “ambient particulate matter pollution” as the fourth-leading factor in premature deaths in China, behind dietary risks, high blood pressure, and smoking. Worldwide, air pollution was the seventh-leading cause of premature death, contributing to 3.2 million deaths, according to the study. While the study was published in The Lancet
, a UK-based medical journal, the summary of China statistics was reported at a forum in Beijing, the New York Times says
. The findings come as public outrage grows in China as residents of many cities endure choking air far in excess of safe levels.
22 Mar 2013:
Expansion of Chinese City Poses
Environmental and Safety Risks, Critics Say
An ambitious plan to expand the western Chinese city of Lanzhou into a regional industrial hub is raising concerns over what critics call lax government oversight of the environmental and safety impacts, including worries that it will siphon huge amounts of water from an already parched region
and devastate nearby mountains. Lanzhou, the capital of Gansu Province, is a city of 3.6 million and a gateway to Tibet and the Xinjiang region. It is known as one of the most polluted cities in China, and now the government is working to expand the city’s footprint by at least 70 percent, according to Caixin Online
. That expansion involves the flattening of mountaintops, and the additional 1 million people and increased industrial activity will draw water from the already polluted and over-stressed Yellow River. Opponents of the plan say buildings will also be constructed on loose soil that will be vulnerable to collapse. “It was a rash decision to begin construction on the new city before receiving environmental approvals or seeking opinions from the Lanzhou public,” said Zhao Zhong, a local activist.
20 Mar 2013:
High-Speed Trains Provide
Environmental, Social Benefits, Study Says
Bullet trains fuel real-estate booms, improve quality of life, reduce air pollution and traffic congestion, and provide a “safety valve” for crowded cities, especially in the developing world, according to a study by Chinese and U.S. economists. The study was based on China’s rapidly expanding high-speed rail network, but the researchers said the benefits experienced there would be similar for California’s proposed high-speed rail system
. Bullet train systems connecting China’s largest cities to nearby smaller cities have made these “second tier” cities more attractive for workers and alleviated traffic congestion and pollution in megacities, according to the study, carried out by economists at Tsinghua University and the University of California, Los Angeles. The study found that the trains created a new category of exurbs within 60 to 470 miles of urban centers such as Beijing, Shanghai, and Guangzhou, helping keep people from moving to already crowded megacities. The study was published in the online version of the Proceedings of the National Academy of Sciences
27 Feb 2013:
Oxfam Ranks Food Giants on
Sourcing and Environmental Policies
The group Oxfam has published an online scorecard assessing the agricultural sourcing of the world’s biggest food and beverage companies, rating them on factors that include water resource management, climate
awareness, and transparency. Using publicly available information, the “Behind the Brands
” campaign rates the 10 companies with the largest overall revenues — including Nestlé, PepsiCo, Unilever, Mars, and General Mills — on their awareness and responsiveness to these issues and supply chain management. According to Oxfam's analysis, Europe-based companies Nestlé and Unilever earned the highest scores overall, receiving good marks for water management and workers’ rights. Seven of the 10 companies received the lowest possible score for land management
. Associated British Foods, Kellogg’s, and General Mills received the lowest overall scores. Oxfam says the scoreboard will be updated regularly.
12 Feb 2013:
Norwegian Retrofit Seeks
To Create ‘Energy-Positive’ Office Buildings
Two office buildings in Norway are being retrofitted so they will generate more power than they use
when the project is completed next year. The three- and four-story buildings, in the town of Sandvika, near Oslo, will generate geothermal and solar energy on site, making the buildings “energy positive,” according to the project's backers. The retrofit will use a heat-retaining black façade, top-quality insulation to reduce energy use by up to 90 percent, and an interior design that will allow air to circulate without fans. “We believe this is the first time in the world that a normal office block is being renovated to such strict standards,” Svein Brandtzaeg, chief executive of Norsk Hydro, one of the project’s partners, told Reuters. According to the UN Environment Programme, the building industry has the greatest potential of any economic sector for large cuts in greenhouse gas emissions.
29 Jan 2013:
Continued Beijing Air Pollution
Triggers Online Call for Clean Air Act
As Beijing residents continue to endure choking air pollution that far exceeds safe levels, an online poll has found overwhelming support for new clean air legislation
. Ten hours after real estate mogul Pan Shiyi
posted the poll on the popular social media platform Sina Weibo, 99 percent of respondents (more than 32,000 people) agreed that the government should enact a Clean Air Act, with many users offering specific measures to curb pollution, including car-free days, stricter auto emissions standards, and public health protections. The dangerous cloud of pollution that has hung over Beijing for about a month now covers roughly 1.3 million square kilometers, according to the government-run Xinhua news agency. In Beijing this week, visibility fell to 500 meters, and some city natives called it the “worst fog ever,” according to China Daily
28 Jan 2013:
Megacities Alter Weather
Across Long Distances, Study Says
Heat generated in major metropolitan areas is altering the character of the jet stream and other atmospheric systems, at times affecting the weather thousands of miles away
, a new study says. Writing in the journal Nature Climate Change
, a team of scientists reports that so-called “waste heat” produced from buildings, cars, and other sources is altering weather patterns and increasing winter temperatures across large areas of North America and northern Asia by as much as 1 degree C (1.8 degrees F). In parts of Europe, however, the changes to atmospheric circulation are causing temperatures to fall by as much as 1 degree C., the study found. “Although much of this waste heat is concentrated in large cities, it can change atmospheric patterns in a way that raises or lowers temperatures across considerable distances,” said Aixue Hu, a scientist at the National Center for Atmospheric Research and one of the lead authors of the study. According to the study, this phenomenon is different than the so-called “heat island effect,” in which cities are warmer than surrounding areas as a result of heat collected and re-radiated by pavement, buildings, and other urban features.
31 Dec 2012:
Network of Smartphone-Based
Sensors Track Air Pollution Levels
Researchers at the University of California, San Diego have developed a network of smartphone-based air pollution monitors
that allow individuals to track
pollution levels in real time and feed a central database of air quality trends citywide throughout the day. The so-called CitySense devices are equipped with sensors that measure ozone, nitrogen dioxide, and carbon monoxide, and a digital app that illustrates the color-coded results based on the U.S. Environmental Protection Agency’s air quality ratings. During a four-week test, in which the phones were distributed to 30 volunteers, the system showed hotspots of elevated pollution that shifted over the course of the day. Ultimately, the developers hope to deploy hundreds of devices in order to generate a public database on air quality levels. “We want more data and better data, which we can provide to the public,” said William Griswold, a computer science professor at UC San Diego. “We are making the invisible visible.”
07 Dec 2012:
Populations of Large, Old Trees
Are Dying Off Worldwide, Report Says
Populations of large, old trees, which provide critical ecosystem services, are declining across the planet
and could eventually disappear altogether in some regions, according to a report by three leading ecologists. Writing in the journal Science
, the scientists say the loss of large trees is occurring in all kinds of forests and at all altitudes, from Yosemite National Park in the U.S., to African savannahs, to Amazon rainforests and northern boreal forests. The losses are being driven by numerous factors, including land clearing, agricultural expansion, human-designed fire regimes, logging, invasive species, and climate change. “We are talking about the loss of the biggest living organisms on the planet, of the largest flowering plants on the planet, of organisms that play a key role in regulating and enriching our world,” said Bill Laurance
, a scientist at James Cook University in Australia, who coauthored the report.
05 Dec 2012:
African Lion Populations
Plummet as Habitat Disappears, Study Says
More than two-thirds of Africa’s lions have disappeared over the last 50 years as the continent’s once-vast savannah regions have been lost to human
A lion in South Africa
development, a new study has found. Using high-resolution satellite images from Google Earth and human population data, Duke University researchers calculated that about 75 percent of the original savannah has been lost since 1960
, driven by land-use changes and deforestation. On the entire continent, they found, there are now just 67 remaining pockets of savannah suitable for lion habitat; only 10 of those areas would be considered lion “strongholds.” Overall, lion populations have dropped from 100,000 to roughly 32,000 in just five decades, according to the study published in the journal Biodiversity and Conservation
. Continued habitat loss projected over the coming decades could put these populations at increased risk, the study said.
Interview: Designing Green Cities
To Meet 21st Century Challenges
Landscape architect Martha Schwartz is a passionate believer in the role that landscape can play in urban sustainability. Great landscape design, she says, can
Martha Schwartz Partners
moderate extreme heat, recycle water, reduce energy use, lower carbon emissions, and attract people to urban areas. Following these principles, her London-based firm, Martha Schwartz Partners
, has designed such projects as Dublin’s Grand Canal Square; Exchange Square, in Manchester, England; and Abu Dhabi’s Corniche beachfront area. In an interview with Yale Environment 360
, Schwartz, a professor at Harvard University’s Graduate School of Design, talks about the importance of incorporating cultural values in urban design, explains why the design of streets and parking lots is as important as the design of parks, and discusses why the U.S. lags behind many other nations in the greening of its cities. Read the interview
04 Dec 2012:
Air Quality Improvements
Continue to Yield Health Benefits
While the rate of improvement of U.S. air quality has slowed during the last decade, even those small improvements have had a beneficial effect on life expectancy, according to new research
. In a study of 545 counties across the U.S., researchers from the Harvard School of Public Health found that a slight decrease of fine particulate matter of 2.5 micrometers or less in diameter — known as PM2.5 — from 2000 to 2007 was associated with an average increase in life expectancy of 0.35 years. During that period, researchers say, concentrations of PM2.5 decreased by 10 micrograms per cubic meter. While that improvement in air quality was far less significant than the pollution reductions observed between 1980 and 2000, the new findings suggest that continued improvements have additional health benefits. “It appears that further reductions in air pollution levels would continue to benefit public health,” said Harvard researcher Andrew Correia, lead author of the study published in Epidemiology
28 Nov 2012:
Scientists Develop Standardized
Analysis of City Pollution Emissions
A team of Israeli researchers has developed a method to track pollution over the world’s mega-cities
, a satellite-based process they say could help hold nations accountable for their pollution and promote cleaner
Smog over Beijing
industrial practices. Using data collected by three NASA satellite systems, the researchers from Tel Aviv University (TAU) collected pollution trends for 189 cities with populations exceeding 2 million. According to Pinhas Alpert, head of TAU’s Porter School of Environmental Study, the research represents the first standardized global analysis of the smog levels in the atmosphere over the world’s largest cities. Based on the data, collected from 2002 to 2010, cities in Northeast China, India, the Middle East, and Central Africa saw the steepest rise in aerosol concentrations, with an average increase of 34 percent. The greatest improvements occurred in Houston, with a 31 percent decrease in aerosol concentrations; Curitiba, Brazil, a 26 percent decrease; and Stockholm, a 23 percent decrease.
21 Nov 2012:
Solar-Equipped ‘iShacks’ Offer
Cheap, Sustainable Housing in South Africa
South African researchers say they have developed a low-cost and sustainable housing alternative to the flimsy corrugated iron shacks found in the country’s growing settlements. Developed by an interdisciplinary
team at Stellenbosch University’s TsamaHUB center
, the so-called iShack is insulated with inexpensive, natural materials such as mud and cardboard boxes and has a sloped roof for harvesting rainwater. A photovoltaic cell on the roof provides the energy for motion-sensitive exterior lighting, interior lighting, and a cellphone charger. So far, a mother and her three children are living in a prototype iShack
in Ekanini, an informal settlement of 8,000 residents in Cape Town that lacks access to electricity and an adequate water supply. Project developers also taught six residents in the community how to install and maintain the solar power system in hopes they can use the skills for future entrepreneurial ventures. Researchers look to apply the iShack’s design to upgrade settlements in other regions.
19 Nov 2012:
Breeding Birds in UK
Have Declined 20 Percent Since 1960s
The population of breeding birds in the UK has plummeted by 21 percent since 1966
, losing more than 44 million birds in less than a half-century, according to the newly released State of the UK’s Birds 2012
report. According to experts, the number of house sparrows has
State of the UK's Birds 2012
The yellow wagtail
dropped from 30 million in 1966, when the first reliable bird-monitoring surveys were conducted, to about 10 million today — a loss of about 50 sparrows every hour. Once-abundant populations of the willow tit have all but disappeared in most regions of the UK, while numbers of the lesser spotted woodpecker and Arctic skua are now too few to number. Populations of farmland bird species are now half of what they were in 1970, according to the report, which draws on information from numerous bird surveys and databases. Land use changes and coastal water management have likely been key factors in these declines, as some species have had increasing difficulty finding suitable places to nest or forage, experts say.
In New York, The Rising Threat Of
Flooding Was Predicted for Years
While climate experts hesitate to say Hurricane Sandy was caused by climate change, scientists for years have predicted that such devastating events would become increasingly common as sea levels rise and ocean
Rising Currents: A 2010 exhibit showed visions of New York adapting to climate change.
temperatures become warmer. For more than a decade, reports have warned that climate change will likely trigger more intense hurricanes and more frequent and severe flooding in low-lying areas
, such as occurred in New York and New Jersey. And with sea levels projected to rise by as much as six inches per decade by mid-century and as much as several feet by 2100,
experts say New York City’s flood zone will continue to expand
. In Sandy's wake, New York officials are starting to discuss projects that might withstand such surges
, including building a levee system or barriers.
17 Oct 2012:
Elevated Levels of CO2
May Impair Cognitive Abilities, Study Says
Elevated levels of carbon dioxide in indoor settings can have a detrimental effect on decision-making abilities and work performance
, according to a new study. In a series of tests, U.S. researchers exposed 22 healthy adults to different levels of carbon dioxide concentrations (600 parts-per-million, 1,000 ppm, and 2,500 ppm) in an office-like room. Under each condition, the participants were asked to take a computer-based test that measured their decision-making abilities. According to the findings, published in the journal Environmental Health Perspectives
, the participants’ performance declined notably on six of nine tests when CO2 levels were increased to 1,000 ppm; performance declined substantially on seven of the tests when levels were bumped to 2,500 ppm. Earlier research has associated increased student absences and poorer performance with higher CO2 levels, said William Fisk, a researcher at the Lawrence Berkeley National Laboratory and co-author of the study. “But we never thought CO2 was actually responsible,” he said. “We assumed it was a proxy for other [pollutants].”