27 Aug 2015:
NASA Study Quantifies Plants'
Role in Mitigating Urban Heat Island Effect
The presence or scarcity of vegetation is an essential factor in determining how much urban areas heat up, according to a NASA study
Using data from multiple satellites, the researchers found that areas covered in part by impervious surfaces such as asphalt, concrete, and steel had an average summer temperature 3.4 degrees F higher than nearby rural areas. The highest U.S. urban temperatures compared to surrounding areas were along the Interstate-95 corridor from Boston to Washington and around Atlanta and the I-85 corridor in the Southeast. In desert cities such as Phoenix, the urban area was actually cooler because irrigated lawns and trees provide cooling that dry, rocky areas do not, the researchers explain. The urban heat island effect occurs primarily during the day, when impervious surfaces in cities absorb more sunlight than surrounding vegetated areas.
Solar Decathlon: The Search for
The Best Carbon-Neutral House
What’s the latest in well-designed, energy-efficient solar homes? The U.S. Department of Energy has invited 15 teams from colleges across the country to design and build affordable, energy-efficient, and attractive solar-powered houses for the 2015 Solar Decathlon. In addition to functioning as comfortable homes, the houses in the competition must produce at least as much energy as they consume. Here, e360
takes a look at some of this year's entries, which will be on display in Irvine, California, this October. These houses have been engineered to not only embrace energy efficiency and sustainable design, but also to meet the diverse needs of their future inhabitants, from food production to storm protection and disaster relief.
View the houses.
29 Jul 2015:
Global Population Projected to
Reach 11 Billion by 2100, U.N. Estimates
The current world population of 7.3 billion is expected to reach 8.5 billion by 2030, 9.7 billion by 2050, and 11.2 billion in 2100,
according to a United Nations report
released today. The revised U.N. estimates counter previous projections, which had said that global population would peak at roughly 9 billion by 2050, then gradually decline. Most growth will occur in developing regions, the new report says, especially Africa, which is expected to account for more than half of the world’s population growth between 2015 and 2050. India is expected to become the most populous country, surpassing China around 2022. Nigeria could surpass the United States by 2050, which would make it the third-largest country in the world, the United Nations projects.
13 May 2015:
Car Travel Is Six Times
More Expensive Than Bicycling, Study Finds
Traveling by car costs society and individuals six times more than traveling by bicycle, according to a study
Bicycles parked in downtown Copenhagen
transportation trends in Copenhagen, one of the planet's most heavily bicycled cities. The analysis considered how much cars cost society and how they compare to bicycles in terms of air pollution, climate change, noise, road wear, public health, and congestion in Copenhagen. If the costs to society and the costs to private individuals are added together, the study found, the economic impact of a car is 0.50 euros per kilometer, whereas the cost of a bicycle is 0.08 euros per kilometer. Looking only at costs and benefits to society, one kilometer by car costs 0.15 euros, whereas society earns
0.16 euros on every kilometer cycled because of improvements in the public's health.
06 May 2015:
Backyard Bird Feeders May Put
Native Species at a Disadvantage, Study Says
Backyard bird feeders tend to attract aggressive, introduced bird species while discouraging native species that eat
A sparrow eats at a backyard bird feeder.
insects and nectar, essentially restructuring urban bird communities and skewing them toward non-native species, a new study
says. Data based on nearly 600 surveys of 18,000 birds from 33 species in New Zealand show that yards with bird feeders tended to attract non-native omnivores such as house sparrows, spotted doves, and blackbirds. Outdoor areas without bird feeders had significantly more native bird species such as the grey warbler, whose diet consists mainly of insects. Although the population trends reversed when feeders were removed, the researchers say that over time bird feeders in urban areas likely give non-native bird species a competitive and reproductive edge over native species.
13 Apr 2015:
Public Transportation Spending
Varies With Income and Geography in the U.S.
Households in different regions of the United States spend similar amounts on transportation, but how those costs break down
Transportation spending trends in the U.S.
between gasoline and public transportation varies widely, according to
data from the Bureau of Labor Statistics. In the South, where the average household owns 2.1 vehicles, spending on gasoline is higher and public transportation spending is lower than in any other region. In contrast, households in the Northeast — which own an average of 1.6 vehicles per household — spend the least on gasoline and the most on public transportation of any region in the U.S. The spending breakdown also varies with income. Households in the highest income bracket spend more than $1,400 annually on public transportation — nearly three times the national average of $537 and eight times the $163 spent by lowest-income households.
07 Apr 2015:
Nationwide Vehicle Emissions
Database Could Help Cities Curb CO2
Researchers at Boston University have created a nationwide database
for determining how much carbon dioxide
Nationwide CO2 emissions from vehicle travel
is produced by vehicle travel in U.S. cities and suburbs — an essential part of greenhouse gas reduction efforts, they say. Encompassing 33 years of data, the system provides kilometer-by-kilometer views of vehicle emission trends from roads across the country. Those emissions account for 28 percent of all fossil fuel CO2 emissions in the U.S., the researchers note. The data highlight the ongoing shift in the U.S. toward urban traffic and emissions. For example, cities have been responsible for 80 percent of the growth in vehicle CO2 emissions since 1980 and for 63 percent of total vehicle CO2 in 2012. Emission levels and trends can vary dramatically across different cities, however. Population density hasn't changed much in Salt Lake City since the 1980s, but the per-capita emissions have soared because the suburb and exurb populations are growing, the data indicate.
24 Mar 2015:
Extreme Forest Fragmentation
Documented in Comprehensive New Study
Fragmentation of the world’s forests has become so severe
that 70 percent of remaining woodlands are now within 1 kilometer of a road or other form of development, according to a new study
. Using the world’s first high-resolution satellite map of tree cover, as well as an analysis of seven long-term fragmentation studies, researchers showed that the ongoing destruction of global forests is decreasing biodiversity by as much as 75 percent in some areas and adversely affecting the ability of forests to store carbon and produce clean water. The study, published in the journal Science Advances
, found that 20 percent of the world’s forests are just 100 meters from a human-created “edge.” Even many parks and protected areas have undergone fragmentation, the study said. The few remaining large, virgin tracts of forest are found in parts of the Amazon, Siberia, Congo
, and Papua New Guinea.
19 Mar 2015:
Electric Vehicles Keep Cities
Cooler than Gas-Powered Cars, Study Says
Electric vehicles emit 20 percent less heat than gas-powered cars, which helps mitigate the urban heat island effect and
An electric car recharges its battery.
could lead to lower air conditioner use in major cities, according to research published in the journal Scientific Reports
. Heat emanating from vehicles is an important contributor to the heat island effect — the difference between temperatures in heavily urbanized areas and cooler rural regions — and a shift toward electric vehicles could help, the researchers say. They used data from Beijing in the summer of 2012 to calculate that switching vehicles from gas to electricity could reduce the heat island effect by nearly 1 degree C. That would have saved Beijing 14.4 million kilowatt hours of electricity from air conditioning and cut carbon dioxide emissions by 11,779 tons per day, the study says.
17 Mar 2015:
California Could Install Ample
Solar Power Without Damaging Habitats
California could generate enough electricity from solar power to exceed the state's energy demand five times over, even if solar equipment were only to be installed on and near existing infrastructure, a report in Nature Climate Change
says. The report shows it is possible to substantially boost California's solar energy production without converting natural habitat, harming the environment, or moving solar installations to remote areas far from consumers. Roughly eight percent California's land area has been developed by humans, the study says, and residential and commercial rooftops provide ample opportunity for generating electricity through small- and utility-scale solar power installations. Additional solar facilities could be constructed in undeveloped areas that are not ecologically sensitive, such as degraded lands, the report notes. "Integrating solar facilities into the urban and suburban environment causes the least amount of land-cover change and the lowest environmental impact," says lead researcher Rebecca R. Hernandez.
06 Mar 2015:
Los Angeles City Council Says
Vegetables Can Be Grown Along Sidewalks
The Los Angeles, California, City Council voted
this week to allow residents to grow fruits
Planting in a parkway in Los Angeles, Calif.
and vegetables in the small strips of city-owned land between the sidewalk and street. Doing so used to require a $400 permit, essentially preventing lower-income residents from using the green spaces, which are also known as parkways. Community groups have been pushing for many years to do away with the permit fee in hopes of improving low-income communities' access to healthy foods, and the council has been working on the ordinance change for almost two years. The mayor is expected to approve the change next week, and if he does, the ordinance will go into effect in 30 days.
24 Feb 2015:
New Map Shows Background
Noise Levels Across the United States
A new map by the U.S. National Park Service (NPS) shows America's quietest and noisiest places. The park service
mapped background noise levels across the country on an average summer day using 1.5 million hours of acoustical data. The quietest areas of the country, such as Yellowstone National Park in Wyoming, are shown in deep blue on this map and are likely as quiet now as they were before European colonization, NPS researchers say. They are collecting the data as part of an effort to determine whether and how wild animals are affected by anthropogenic noise pollution. Owls and bats, for example, rely on hearing faint rustles from insects and rodents, and scientists think human-driven noise could be drowning out those subtle signals in many areas of the country.
19 Feb 2015:
New York City Set for Major
Sea Level Rise By 2050, Report Concludes
The waters surrounding New York City are on track to rise 11 to 21 inches by the 2050s, according to an analysis
NASA climate change models. The city's average temperature, which has increased by 3.4 degrees F since 1900, is set to rise another 5 degrees F by the 2050s, the report says, and annual precipitation is also likely to rise significantly over that period. New York City has already seen sea levels rise by over 1 foot since 1900 — nearly twice the average global rate, according to the report, which was published by the New York City Panel on Climate Change. Mayor Bill de Blasio said the report highlights the urgency of mitigating climate change and adapting to its risks, and he announced a commitment
to cut the city's emissions by 80 percent by 2050.
03 Feb 2015:
Nine of 10 Cities in China Failed
Air Quality Standards, Government Says
Roughly 90 percent of China's large cities did not meet national air quality standards last year, according to the country's
Smog over the Forbidden City in Beijing, China.
environment ministry. Only eight of the 74 cities monitored by the ministry met standards for pollution metrics such as ozone, carbon monoxide, and fine particle concentrations, according to a report published on the ministry's website. The poor results actually represent an improvement over 2013, when only three of the 74 cities met air quality standards, Reuters reports
. Last year, after residents grew increasingly alarmed about air quality in metropolitan areas, China promised to "declare war on pollution" by slashing coal use and closing heavily polluting factories. Still, the government does not expect the national average for fine particle pollution to reach official standards until 2030 or later.
21 Jan 2015:
Filtering Polluted Stormwater
Through Soil Can Protect Salmon, Study Says
Filtering polluted runoff from urban areas through a simple soil mixture dramatically reduced the water's toxic metal and
A pair of coho salmon.
hydrocarbon content and made it safe for coho salmon and the insects they eat, according to new research
. Scientists collected polluted runoff from a four-lane highway in Seattle, then filtered part of the water through a mixture of sand, compost, and shredded bark. Coho salmon and aquatic insects thrived in the filtered stormwater, but they quickly died in the unfiltered water, researchers reported in the journal Chemosphere
. Chemical analyses showed that filtering the water through the soil mixture reduced toxic metals by 30 to 99 percent, polyaromatic hydrocarbons to levels at or below detection, and organic matter by more than 40 percent. The research supports the use of rain gardens and other natural stormwater filtration systems, the authors say.
05 Jan 2015:
U.S. Cities Are Significantly
Brighter than German Cities, Scientists Say
German cities emit several times less light per capita than similarly sized American cities, according to new research
published in the journal Remote Sensing
Berlin, Germany, at night
Moreover, the differences in light emission become more dramatic as city size increases: Light per capita increases with city size in the U.S. but decreases in Germany. Factors such as the type of lamps used and architectural elements like the width of the streets and the amount of trees are likely behind the differences, the researchers say. Energy-efficient LED street lighting
is currently being installed in many cities worldwide, and the researchers expect this to change the nighttime environment in many ways — for example, by reducing the amount of light that shines upward. The study also found that, in major cities in developing countries, the brightest light sources were typically airports or harbors, whereas the brightest areas in large European cities are often stadiums and city centers.
23 Dec 2014:
Madrid Announces Largest
Energy-Efficient Street Lighting Project
The city of Madrid has announced plans
to renew its entire street lighting system with 225,000 new energy-efficient
New energy-efficient street lighting in Madrid, Spain.
bulbs, the world’s largest street-lighting upgrade to date. The new lights, which will afford the city a 44-percent reduction in energy costs, will pay for themselves, according to Philips
, the company supplying the new system. In addition to drawing less overall power, the bulbs’ intensity will be controlled from a central command panel, resulting in less wasted energy. Of the 225,000 new lights, 84,000 will be locally manufactured LEDs, and the city is taking measures to ensure the safe recycling of heavy metals found in the old lamps. Similar, though smaller, projects have been undertaken in Argentina, Sweden, and the Netherlands.
25 Nov 2014:
China’s Lake Ebinur Has Been
Shrinking Dramatically, NASA Image Shows
As this NASA satellite image shows
, Lake Ebinur, located in northwestern China near the border of
Kazakhstan, has shrunk by 50 percent since 1955 as a result of development, agriculture, and natural fluctuations in precipitation. The lake’s saline water is light blue, and the dried lake bed appears white due to salts and other minerals that have been left behind as the water evaporates. The lake’s size fluctuates from year to year due to natural variations in snowmelt and rainfall, and human activity also plays a key role, Chinese researchers say. The nearby city of Bole, with a population of 425,000, consumes significant amounts of water, and farmers irrigate their crops — especially cotton — with water that would otherwise flow into the lake, researchers say. Frequent saline dust storms contribute to desertification, damage soils, harm wetlands, and may be hastening the melting of snow and glaciers downwind, researchers say.
06 Oct 2014:
Number of Megacities Has
Nearly Tripled Since 1990, UN Report Says
The number of urban areas with more than 10 million inhabitants — sometimes called "megacities" — has
nearly tripled in the last 24 years, jumping from 10 in 1990 to 28 in 2014, according to the latest UN report on world urbanization
. The total number of people living in megacities has grown from 153 million to 453 million during that period, the report says, and such areas now account for 15 percent of global GDP. Although densely populated urban areas can be environmental blights, innovations in efficient transportation have arisen from some major cities in Asia and Lagos, Nigeria, because those cities have invested heavily in public transit infrastructure, researchers say
15 Sep 2014:
Urban Air Pollution May
Affect Brains of Young Children, Study Says
Children living in areas with high air pollution are at increased risk for brain inflammation and for developing
Smog over Mexico City
neurodegenerative conditions such as Alzheimer's and Parkinson's disease, according to
a study by researchers at the University of Montana. The scientists compared brain and spinal fluids of children living in low-pollution areas to those of children living in Mexico City, an area notorious for its poor air quality. They found that children living in the city had significantly increased levels of combustion-related metals in their systems, as well as higher levels of antibodies related to inflammation. The antibodies are an indicator of autoimmune response and are possibly tied to higher risks for neurodegenerative conditions such as Alzheimer's and Parkinson's disease, according to the researchers. They say that a study following the Mexico City children as they age is needed to determine whether there is a relationship between their autoimmune responses and documented brain and cognition changes.
05 Sep 2014:
Smog in India Damaged
Enough Crops to Feed 94 Million, Study Says
Ground-level ozone, the main component of smog, damaged 6.7 million tons of Indian crops worth an
Smog in Delhi, India
estimated $1.3 billion in a single year, according to
a new study published in Geophysical Research Letters
. That's enough wheat, rice and other staple crops to feed 94 million people — roughly one-third of the country's impoverished population. Arising from a combination of vehicle emissions, cooking stoves, and industrial sources, plant-damaging ozone has left many of India's fast-developing cities among the most polluted in the world, according to the country's Air Monitoring Center. The number of vehicles there has nearly tripled in the past 10 years, rising from 50 million in 2003 to 130 million in 2013, and the country currently has no air quality standards to protect crops from ozone pollution. The researchers say the findings should be used to guide new ozone emission standards for the country.
26 Aug 2014:
Meat Production, Especially
Beef, Strains Land and Water, Study Says
Global meat production has expanded more than four-fold over the last 50 years — and 25-fold since
Beef cattle graze in Colombia
1800 — due to growing purchasing power, urbanization, and changing diets, according to a new report from the Worldwatch Institute
. Consumers in industrial countries still eat much larger quantities of meat (75.9 kilograms per person) than those in developing nations (33.7 kilograms), though that gap is beginning to close, the report says. Nearly 70 percent of the planet's agricultural land and freshwater is used for livestock, with additional land and water used to grow grains for livestock feed. Beef production alone uses about three-fifths of global farmland and yields less than 5 percent of the world's protein, according to the report. Sustainable agricultural practices
such as feeding livestock with grasses instead of grains and using natural fertilizers could reduce these impacts, the report notes, but alternative dietary choices hold the most immediate promise for reducing the environmental footprint of meat production.
04 Aug 2014:
California Takes Steps to
Curb Lawn Watering During Severe Drought
In the midst of a severe, long-term drought, California is taking unprecedented steps to discourage watering of
A drought-resistant yard
residential lawns, with some areas offering residents substantial cash incentives for installing water-saving landscaping, AFP reports
. The "Cash in Your Lawn" program in Los Angeles offers residents up to $6,000 ($3 per square foot) for replacing their lawns with drought-tolerant plants, rocks, and pebbles. Throughout the state, Governor Jerry Brown recently prohibited lawn watering more than two times per week and banned fines for brown lawns, which homeowner associations sometimes impose with the intent of improving a neighborhood's appearance. The drought, currently in its third year, threatens the water supply of California's 38 million residents. Agricultural regions
have already seen severe water reductions, placing extra pressure on the state's groundwater reserves.
22 Jul 2014:
Costs of Urban Light Pollution
Highlighted in Citizen Science Effort
A recently launched citizen science
project aims to highlight the environmental, social, and financial impacts of excessive nighttime lighting in cities around
the world. The project, called Cities at Night
, enlists people to help identify the cities pictured in thousands of blindingly lit photos taken by astronauts orbiting the earth. Organizers hope that when residents and officials see the bright photos of their cities at night, they will be prompted to cut nighttime light use and energy consumption. Widespread artificial lighting has made light pollution
a growing problem in urban areas by disrupting behavioral patterns of people and wildlife, wasting millions of dollars in energy costs, and adding greenhouse gases to the atmosphere. Some solutions are relatively inexpensive and straightforward, the organizers say, such as using shields to direct light down to street-level, which can allow a city to use lower-wattage streetlights.
03 Jul 2014:
Human Activity Has Boosted
Plant Growth Globally, NASA Data Show
On a global scale, the presence of people corresponds to more plant growth, according to
an analysis of three decades of global vegetation greenness data from
Agriculture has increased global vegetative cover.
satellites. More than 20 percent of global vegetation change can be attributed to human activities, such as agriculture, nitrogen fertilization, and irrigation, rather than climate change, researchers report in the journal Remote Sensing
. The findings suggest that global climate change models, which typically don't consider human land use, should take into account the relatively large impact human settlements can have on vegetative cover, the researchers say. From 1981 to 2010, areas with a human footprint saw plant greenness and plant productivity increase by up to 6 percent, while areas with a minimal human footprint, such as rangelands and wildlands, saw almost no change. Most increases in growth and greenness were seen near rural areas and villages, where agriculture is more intense.
09 Jun 2014:
Air Conditioning Can Raise
Urban Nighttime Temperature by 2 Degrees
Excess heat from air conditioners raises outdoor temperatures at night by nearly 2 degrees F (1 degree C), worsening the urban heat island effect and increasing cooling demands, according to research
from Arizona State University. Studying the Phoenix metropolitan area, researchers found that air conditioning systems pumped more waste heat into the air during the day, but the effect on near-surface temperatures was negligible. The same was not true for nighttime temperatures, however, when waste heat significantly boosts air temperatures because of nighttime atmospheric conditions. Air conditioning systems can consume more than 50 percent of total electricity
during extreme heat, the researchers note, and summertime extreme-heat days are projected to become more frequent and intense as a result of climate change. Redirecting waste heat from air conditioning systems to household appliances such as water heaters, for example, could help alleviate the problem, the scientists say. They project that such strategies would save at least 1,200 to 1,300 megawatt-hours of energy per day in the Phoenix metropolitan area alone.
Interview: Putting San Francisco
On the Road to Zero Waste by 2020
For 20 years, Jack Macy has spearheaded San Francisco’s efforts to become a global leader in recycling. In an interview with Yale Environment 360
Macy describes how San Francisco has succeeded in reusing or composting 80 percent of its garbage and how the city has engaged the public in a recycling crusade, allaying initial fears of “trash police” sifting through residents’ garbage. While San Francisco has made tremendous progress, Macy says further changes are needed. “Part of the principle of zero waste is that the local government can’t shoulder all the burden,” he says, “so it’s important that we encourage consumers to take responsibility for what they buy ... and producer responsibility for the products they design and market.”
05 May 2014:
New European Satellites
To Give More Detailed Views of Earth
The European Space Agency has begun launching
a series of satellites designed to collect detailed environmental data around the globe — from radar-based, high-definition imagery to information about the
atmosphere's chemical composition. The first satellite in the ESA's Copernicus program, the Sentinel 1A, was launched last month and has already returned many striking images based on radar data, such as this view of Brussels, Belgium, in which the dense urban area contrasts with the city's heavily vegetated surroundings. Once Sentinel satellite 1B is launched next year, the two will be able to map the entire globe in six days, giving researchers and conservationists a powerful way to monitor both short- and long-term changes in the environment. Four additional groups of satellites are set to launch this year. Those arrays will focus on high-resolution photo imagery, topography, surface temperatures, and atmospheric chemistry.
10 Apr 2014:
Mapping Program Helps
Cities See Money Saved by Planting Trees
New open-source software is helping cities better understand the benefits trees provide by calculating the value of the trees' ecosystem services, such as air quality improvements and CO2 storage. More than a dozen
cities have undertaken tree inventory initiatives, thanks to the OpenTreeMap software
, and residents have helped map more than 1.1 million trees worldwide. In addition to plotting a tree's location, users record its size, species, and other parameters that allow the software to calculate the tree's ecological value in terms of dollars saved through such benefits as cleaner air. San Diego's more than 340,000 mapped trees
, for example, are estimated to provide the city more than $7 million in benefits each year, including $4 million in air quality benefits and $2 million in reduced energy costs. In the coming months, the software will allow city managers to decide where to plant trees for maximum environmental benefit.
08 Apr 2014:
'Living Fences' Dramatically
Cut Livestock and Lion Killings in Tanzania
A novel, low-tech idea is helping Tanzania's lion population rebound: So-called "living fences" — which enclose livestock and are constructed of actively growing trees and chain-link fencing — have cut lion
A Masai villager installs a living fence.
attacks and retaliatory killings by more than 85 percent in the areas they've been installed, the Guardian reports
. Traditionally, the Masai have built livestock enclosures out of thorny acacia trees, but those fences are relatively fragile. Chain-link fencing alone is more durable, but leopards and small lions can scale the fences, and hyenas can tunnel in below. By interweaving actively growing African myrrh trees with the chain link fencing, the Masai have created a barrier that lions can't climb over, and their root systems prevent predators from digging under the fence. Because livestock predation has been cut, communities that had been killing six or seven lions annually now kill, on average, less than one, leading to a rebound in lion populations.