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: The Small College That
Launched Fossil Fuel Divestment
When Stanford University announced in May that it would divest its endowment of coal mining companies, it was following the lead of a tiny college in rural Maine
that dubs itself “America’s environmental college.” A year and a half earlier, Stephen Mulkey, the president of Unity College
stood on a stage with Bill McKibben, the founder of 350.org and lead cheerleader for the divestment movement, to announce that his college would be the first institution of higher learning to rid its endowment of all fossil fuel holdings. In an interview with Yale Environment 360
, Mulkey, a climate scientist, talks about the ethical imperative behind the decision to divest, and his vision for, as he puts it, a re-engineering of the way the environmental sciences are taught.
06 Jun 2014:
Brazil Leads the World
In Cutting Deforestation, Analysis Finds
Brazil has become the world leader in reducing deforestation and, at the same time, has increased its soy and beef production, researchers report
Amazon rainforest near Manaus, Brazil
. The country has cut its forest loss by 70 percent since 2004, sparing more than 86,000 square kilometers of rainforests and keeping more than 3.2 billion tons of carbon dioxide out of the atmosphere. Brazil's decline in deforestation in 2013 alone represented a 1.5 percent reduction in global emissions that year, the report says; globally, tropical forest loss
accounts for 15 percent of global carbon dioxide emissions. The analysis credits the success to bold government policies, pressure from environmental groups, and market fluctuations in the price of soy and beef, but the authors warn that these wins may be short-lived without more positive incentives for farmers. “These gains are globally significant, but fragile,” one researcher explained. “We’re bumping up against the limits of what can be achieved through punitive measures.”
05 Jun 2014:
Coating for Roof Tiles Could
Help Clear Smog-Causing Air Pollutants
Engineering students have created a roof tile coating
that, when applied to an average-sized residential roof,
Coated tiles (left) and an uncoated tile (right).
breaks down the same amount of smog-causing nitrogen oxides per year as a car driven 11,000 miles makes. If applied to one million roofs, the titanium-dioxide based coating, which costs roughly $5 per roof, could clear 21 tons of nitrogen oxides each day, the team calculated. That could put a noticeable dent in atmospheric levels of the pollutant; in Southern California, for example, an average of 500 tons of nitrogen oxides are emitted daily. The team, which was recently recognized in a U.S. Environmental Protection Agency student design contest, showed that their tiles could remove 88 to 97 percent of nitrogen oxides in laboratory tests — a feat that other roof tile prototypes have not demonstrated.
04 Jun 2014:
New Ozone-Depleting Gases
Discovered in Atmosphere, Researchers Say
Researchers this week identified three new ozone-depleting gases
in the atmosphere, bringing the total number of such gases discovered this year to seven.
Ozone hole as of September 2013
Alone, none of the three gases were found in concentrations high enough to harm the ozone layer, researchers from the University of East Anglia. But the scientists believe more such gases will likely be discovered, and, cumulatively, they could have a significant impact. Two of the newly discovered gases are chlorofluorocarbons (CFCs) and one is a hydrochlorofluorocarbon (HCFC), both of which were once widely used in refrigerants. All three of the newly discovered gases are likely man-made, researchers said. Both CFCs and HCFCs fall under the Montreal Protocol
, an international agreement that bans the use of 13 such compounds. Including the four new gases discovered earlier this year, there are now a total of 20 known ozone-depleting gases.
03 Jun 2014:
Developing Countries Lead
Global Surge in Renewable Energy Capacity
The number of developing nations with policies supporting renewable energy has surged more than six-fold in just eight years, from 15 developing countries
in 2005 to 95 early this year, according to a report from REN21
, an international nonprofit renewable energy policy network. Those 95 developing nations today make up the vast majority of the 144 countries with renewable energy support policies and targets in place. The report credits
such policies with driving global renewable energy capacity to a new record level last year — 1,560 gigawatts, up 8.3 percent from 2012. More than one-fifth — 22 percent — of the world's power production now comes from renewable sources. Overall, renewables accounted for more than 56 percent of net additions to global power capacity in 2013, the report says. Although financial and policy support declined in the U.S. and some European countries, China, the U.S., Brazil, Canada, and Germany remained the top nations for total installed renewable power. China's new renewable power capacity surpassed new fossil fuel and nuclear capacity for the first time, the analysis found.
02 Jun 2014:
New U.S. Coal Plant Rules
Could Lead to a Steep Drop in Emissions
The Obama administration today unveiled a sweeping new plan
that aims to cut carbon dioxide emissions from the nation’s 600 coal-fired power plants by roughly a third. Gina McCarthy, administrator of the U.S. Environmental Protection Agency, said the new rules would give states maximum flexibility
to achieve the goal of reducing power plant emissions 30 percent below 2005 levels by 2030. Hundreds of coal-fired power plants are expected to close under the EPA plan. But rather than immediately shutting down plants, states would be allowed to reduce emissions by making changes across their electricity systems — by installing new wind and solar generation or energy-efficiency technology, continuing to expand the use of natural gas, and by starting or joining state and regional “cap and trade” programs. “There is no one-size-fits-all solution ... so each state’s path can be different,” said McCarthy. The proposed regulations could be held up by legal challenges. Obama administration officials said the rules would lift the U.S. into a clear global leadership position
on combating global warming.
30 May 2014:
New Battery Technology
Could Offer Cheap Renewable Energy Storage
New battery technology that uses cheaper and safer materials to store large amounts of energy may soon enable utility companies to use more renewable power,
Iron-chromium flow battery technology
MIT Technology Review. The new device is a type of flow battery, and it uses liquid materials that rely on iron-chromium chemical reactions to store energy. California-based startup Enervault, developer of the new battery, figured out how to use materials that had been tried in batteries decades ago; Enervault overcame a key technical challenge that had caused the earlier batteries to quickly degrade. The new battery is large — it can store one megawatt-hour of electricity, or enough to run 10,000 100-watt light bulbs for an hour — and the materials last more than 20 years, according to its developer. Although the battery is inefficient compared to conventional batteries — it loses 30 percent of the energy used to charge it — it is still economically viable, the company says. The iron-chromium flow battery costs 80 percent less than vanadium flow batteries, a competing technology. The batteries are currently in use at a small power plant near Modesto, California.
29 May 2014:
Electric Airplane Debut
Offers Hopes for Cutting Emissions
The aircraft manufacturing giant Airbus recently unveiled
a fully-electric aircraft which, if widely adopted, could reduce the aerospace industry's carbon
The recently debuted, fully-electric E-Fan
dioxide emissions by an order of magnitude. The E-Fan aircraft has two, 30-kilowatt electric motors powered by a series of lithium-ion batteries in the wings of the plane, as well as a 6-kilowatt electric motor in the wheel to provide extra power during takeoff and taxiing. Despite incorporating highly energy-efficient and aerodynamic design elements, however, the E-Fan has only a one-hour range and cannot leave the vicinity of the airport. Airbus says that future designs will rely on electric-hybrid engine technology and that by 2050 such airplanes should be able to accommodate 70 to 80 passengers on a three-hour flight. The plans were spurred, in part, by the European Union's Flight Path 2050
, which aims to reduce the aviation sector's nitrous oxide emissions by 90 percent, noise pollution by 65 percent, and carbon dioxide emissions by 75 percent by 2050. "It's a very different way of flying," said Jean Botti, a technology officer at Airbus Group, "absolutely no noise, no emissions."
Video Report: Americans on the
Front Lines of Climate Change
A fire chief in Colorado whose department is battling increasingly intense blazes in the American West. A Texas rancher struggling to operate in the face of years of drought. Oyster farmers in Washington state scrambling to adapt to increasingly acidic waters that are damaging their harvests. These Americans are the subjects of videos created by The Story Group
, a non-profit journalism initiative. The videos are meant to put a human face on the science behind the recently released National Climate Assessment
, which stressed that global warming is already having a major impact on the United States.
Watch the videos.
27 May 2014:
To Sway the U.S. Public,
‘Global Warming’ Beats out ‘Climate Change’
If politicians and scientists want to convey the urgency and importance of a warming world, they are far better off using the term "global warming"
than “climate change,” according to a new report. Produced by researchers at the Yale Project on Climate Change Communication and George Mason University, the report
says that Americans are much more familiar with the term “global warming” and that it engenders more negative associations and concern. Based on recent surveys, the report said moderates, women, Hispanics, political independents, and younger Americans associate “global warming” with alarming developments such as melting glaciers and extreme weather. Among many groups, “global warming” also creates a greater sense of threat to one’s family and future generations. “Scientists often prefer the term climate change for technical reasons, but should be aware that the two terms generate different interpretations among the general public and specific subgroups,” the report said. The survey found that among Republicans the two terms are generally synonymous.
23 May 2014:
Oil Drilling Permits
Issued for Key Area of Yasuni Park
The Ecuadorean government has issued permits to begin oil drilling
in a key area of the Yasuni Biosphere Reserve and National Park
, one of the most biodiverse places on the planet. Environment Minister Lorena
Tapia said the government had signed permits to begin preparations for drilling in the so-called ITT section of the park, which contains two uncontacted indigenous tribes; drilling itself could begin as early as 2016, the government said. Ecuador’s President, Rafeal Correa, had offered to ban drilling in large sections of the park if the international community raised $3.6 billion to compensate the country for leaving the oil in the ground. But after only $13 million was raised, Correa gave the green light to drilling, saying “the world has failed us.” Oil drilling has already taken place in some areas of the 6,500-square-mile park. As this Yale Environment 360 video
shows, Yasuni is home to a remarkable array of species, including roughly 400 species of fish, 600 species of birds, and thousands of species of vascular plants and trees.
22 May 2014:
Donors Commit $220 Million
To Protect and Expand Huge Amazon Reserve
A coalition of private donors and government funders has pledged $220 million
over the next 25 years to better protect the Amazon Region Protected Areas (ARPA), the world’s largest protected area network. WWF, the World Bank, the Gordon and Betty Moore Foundation, the Inter-American Development Bank, and more than a dozen other donors are contributing funds to the initiative, which also will add another 8.9 million hectares of Amazon rainforest to the ARPA program
, driving the total to more than 60 million hectares. That’s 232,000 square miles, an area larger than France. Most of the funds will be used to better police and enforce environmental laws on ARPA territory, which includes 90 parks and comprises 15 percent of the Brazilian Amazon. "The explosion in demand for natural resources has made our parks and world heritage sites vulnerable," said WWF president Carter Roberts. The initiative is also upgrading long-neglected parks and creating sustainable-use reserves for local communities and indigenous people.
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.”
21 May 2014:
Trash-scooping Water Wheel
Cleans up Garbage From Baltimore Harbor
A new contraption
in a Baltimore river is helping to clear trash and debris — up to 50,000 pounds of it each day — from the city's Inner Harbor. The 50-foot-long
"water wheel" gathers garbage floating in the Jones Falls River, which runs through the city to the Baltimore Inner Harbor, and deposits it in a large dumpster so the trash can be hauled away. Two large booms funnel debris toward a conveyor belt powered by the wheel, which itself is powered primarily by the flowing river. When the flow isn't strong enough to turn the wheel, water pumps, run by solar panels lining a canopy over the wheel, turn on and push water up to spin the wheel. The water wheel was designed to handle the heavy debris and larger pieces of trash that the river often carries, said its designer, Baltimore-based Clearwater Mills. It began operating earlier this month and cost $750,000, with $500,000 of that contributed by the Maryland Port Administration, Co.Exist reports.
20 May 2014:
Widespread Greenland Melting
Due to Forest Fires and Warming, Study Says
Rising temperatures and ash from Northern Hemisphere forest fires combined to cause large-scale surface melting of the Greenland ice sheet in 2012, an
echo of a similar event that occurred in 1889, a new study
finds. The massive Greenland ice sheet — the second largest ice body in the world after the Antarctic ice sheet — experiences annual melting at low elevations near the coastline, but surface melt is rare in the dry snow region in its center. In July 2012, however, satellites observed for the first time surface melt across more than 97 percent of the ice sheet, generating reports that the event was almost exclusively the result of climate change. In the new report, published in the journal Proceedings of the National Academy of Sciences
, researchers found that in both 2012 and 1889 exceptionally warm temperatures combined with black carbon sediments from Northern Hemisphere forest fires to darken the surface of the ice sheet to a critical albedo threshold, causing the large-scale melting events. Since Arctic temperatures and the frequency of forest fires are both expected to rise with climate change, large-scale melt events on the Greenland ice sheet may begin to occur almost annually by 2100, the researchers say.
19 May 2014:
India's New Prime Minister
Plans To Make A Major Push on Solar Energy
India's new government plans to bring electricity to the homes of its entire population of 1.2 billion within the next five years, largely through solar panel installations,
Bloomberg News reports
. Although nearly 400 million Indians do not have access to electricity, newly elected prime minister Narendra Modi, who won an overwhelming victory in last week's national vote, has pledged to enable every household to run at least one light bulb by 2019. If all goes well, household solar projects would allow every home to run two light bulbs, a solar cooker, and a television, one of Modi's energy advisers said. The plan follows an unfulfilled pledge from the previous administration to bring electricity to all homes by 2012. Modi, who pioneered India's first incentive program for large-scale solar projects when he was chief minister of Gujarat state, has made expanding solar a top priority because it has the potential to create jobs and supply power to millions of households, many of which are scattered throughout rural areas and not connected to the grid
. "We look upon solar as having the potential to completely transform the way we look at the energy space," said the energy adviser.
16 May 2014:
U.S. Honeybee Death Rate
Too High for Long-term Survival, Study Says
Honeybees in the United States are dying at a rate too high to ensure their long-term survival, according to a new report
from the U.S. Department of Agriculture
(USDA). Over the past winter — a season when honeybee hives are most vulnerable — the U.S. lost 23.2 percent of its hive honeybee population. That is lower than the previous winter's 30.5 percent death rate, but the cumulative impact on honeybee populations over the past eight years poses a major threat to their long-term survival, as well as the country's agricultural productivity, the USDA said. Roughly a quarter of U.S. crops depend on honeybees for pollination. "Yearly fluctuations in the rate of losses like these only demonstrate how complicated the whole issue of honey bee heath has become," said a USDA researcher, citing factors such as viruses, pathogens, and pesticides. One class of pesticides
in particular, neonicotinoids, has been implicated in honeybee deaths. The European Union banned three widely used neonicotinoids last year, but they are still used in the U.S.
15 May 2014:
Intensity of Hurricanes
Now Peaking Farther From the Equator
Powerful, destructive tropical cyclones are now reaching their peak intensity farther from the equator and closer to the poles, according to a new study
in the journal
Hurricane Sandy's progression in 2012
. Over the last 30 years, tropical cyclones, also known as hurricanes or typhoons, have moved poleward at a rate of roughly 33 miles per decade in the Northern Hemisphere and 38 miles per decade in the Southern Hemisphere. Ocean temperatures between 82 and 86 degrees F seem to be "ideal for the genesis of tropical cyclones," said MIT scientist Kerry Emanuel, who co-authored the study, "and as that belt migrates poleward, which surely it must as the whole ocean warms, the tropical cyclone genesis regions might just move with it." The poleward shift of hurricanes and typhoons could lead to "potentially profound consequences to life and property" in regions that previously had not been hit by tropical cyclones.
Five Questions for John Holdren
On the U.S. Climate Assessment
The federal government this month released its National Climate Assessment
, the most comprehensive report to
John P. Holdren
date on the climate impacts already being felt in the U.S. Saying climate change “has moved firmly into the present,” the report documented how drier regions are growing drier, heat waves more intense, and large swaths of forest dying from insect infestations. Yale Environment 360
asked John P. Holdren, director of the White House Office of Science and Technology Policy, five questions about the report and about plans by President Obama to intensify actions to rein in CO2 emissions and adapt to rising seas and other changes. Read more.
14 May 2014:
Early El Niño Conditions
May Spell Big Weather Impact This Year
Indications are growing that an El Niño weather pattern may be forming in the Pacific Ocean, which could have a profound impact on global weather. El Niño events are spawned by unusually warm ocean waters in the Pacific,
and these NASA satellite images
are one indication of warmer waters. The images depict sea-surface height anomalies, with above average sea-surface height shown in various shades of brown. Above average sea-surface heights are an indication of warmer waters, which expand as temperatures rise. These two images compare conditions in 1997 — a year with one of the most powerful El Niño events of the 20th century — with conditions this May. If an El Niño pattern does develop this year, it could lead to wetter conditions in western North America and South America, which could help end a severe drought now plaguing the U.S. West. The 1997/98 El Niño also created warmer and drier conditions in much of Asia. Other evidence, including data from a network of buoys in the Pacific, also shows a deep pool of warm waters sliding east across the Pacific since January.
Interview: Can Marine Life Adapt
To the World’s Acidifying Oceans?
As the world’s oceans grow more acidic from increased absorption of atmospheric carbon dioxide, marine scientists are confronting a key question: How well can
organisms like mollusks, crustaceans, and corals adapt to these more corrosive conditions? One of the leading authorities in this field is University of California, Santa Barbara marine biologist Gretchen Hofmann. Her work in recent years has shown, in fact, that some sea organisms that build shells do seem to have some ability to acclimate to more acidic waters. But in an interview with Yale Environment 360
, Hofmann cautions that this adaptive capacity has its limits. The continuing burning of fossil fuels, she says, could push ocean acidity past a tipping point, rendering some mollusks and other organisms unable to build shells.
Read the interview.
13 May 2014:
Half of U.S. is Experiencing
Some Degree of Drought, Analysis Finds
Half of the United States is in the midst of a drought, a recent analysis
from the U.S. National Drought Monitor found, with nearly 15 percent of the nation in extreme to
exceptional drought. Dry conditions are pushing north rapidly, along with warmer temperatures, and soil moisture and groundwater levels are low far in advance of the agricultural peak demand season, according to the National Drought Mitigation Center. Much of the Southwest and Great Plains regions have been in a persistent drought for several years, and as this map prepared by federal agencies shows, an exceptional drought is currently plaguing parts of those regions. The entire state of California is experiencing some level of drought, much of it extreme to exceptional. Snowpack is at half its typical level in many parts of the West and much of the snow has completely melted before it normally would, researchers say. The map is based on measurements of climate, soil, and water conditions from more than 350 federal, state, and local observers around the country.
12 May 2014:
Global Renewable Energy Jobs
Grew by 14 Percent in 2013, Report Says
Renewable energy jobs grew by 14 percent to 6.5 million employees worldwide last year, led by the solar panel industry, according to a new report
from the International Renewable Energy Agency. Employing a
total of 2.6 million workers in renewable energy jobs, China led in hiring last year, followed by Brazil and the United States. The solar industry — spurred by increasing photovoltaic panel installations in Asia and falling prices — employed 2.27 million workers at the end of 2013, largely concentrated in China, the report said. The biofuel industry, with 1.45 million employees, and wind energy, with 830,000, were the second- and third-largest employers. Although policy changes in several countries have reduced wind energy installation jobs, operations and maintenance positions have experienced some growth, according to the report.
09 May 2014:
Biodiversity, But Not Community
Composition, Surprisingly Stable Over Time
A major turnover of species in habitats around the globe is underway, resulting in the creation of novel biological communities, but overall species diversity is much more
stable than scientists had believed, according to a new report
in the journal Science
. In a survey of 100 long-term biodiversity monitoring projects in a variety of habitats around the world, the authors found that the majority of those studies (59 percent) documented increasing species richness. Biodiversity declined in 41 percent of the studies, but, in all cases the overall change in biodiversity was modest, the researchers said. When looking at changes in the species constituting those communities, however, the researchers found a surprisingly high rate of change — an average of about 10 percent change per decade. "A main policy application of this work is that we're going to need to focus as much on the identity of species as on the number of species," one of the study's authors said. "The number of species in a place may not be our best scorecard for environmental change."
08 May 2014:
Natural Variations May Account
For Up to Half of Greenland's Warming
Up to half of the recent climate change in Greenland and surrounding regions — which have warmed at roughly twice the pace of the rest of the planet since 1979 — may be due to natural climate variations that originate in the tropical Pacific and are not connected
Meltwater from Russell Glacier
with the overall warming of the Earth, a new study
says. Still, at least half the warming remains attributable to rising global carbon dioxide emissions, according to research published in the journal Nature
. Climate data and advanced computer models show that changes in the western tropical Pacific Ocean, which has been about 0.3 degrees warmer than normal, have caused shifts in atmospheric pressure over the North Atlantic. Those changes set off a stationary wave in the atmosphere that arcs in a great circle from the tropical Pacific toward Greenland, pulling warmer air over that massive island. "Along this wave train there are warm spots where the air has been pushed down, and cold spots where the air has been pulled up," one author explained. "And Greenland is in one of the warm spots."
07 May 2014:
Stanford Drops Coal Stocks
From Its $18.7 Billion Endowment Portfolio
Stanford has become the first major U.S. university to divest its shares in coal-mining companies from its endowment funds, lending support to a growing nationwide movement calling for universities and
Fossil Free Stanford
pension funds to drop investments in fossil fuel companies. Citing guidelines that allow trustees to weigh whether “corporate policies or practices create substantial social injury” when choosing investments for the university's $18.7 billion endowment, the board decided, after five months of deliberation, to purge stakes in up to 100 companies worldwide that derive profits primarily from coal mining. A Stanford spokeswoman said that coal companies constitute a small fraction
of the university's total endowment investments, “but a small percentage is still a substantial amount of money." Board members said their decision was made partly because coal is the most carbon-intensive of any major fossil fuel and that less carbon-intensive energy sources are available.
06 May 2014:
Darwin's Finches Fight Off
Parasitic Maggots with Treated Nest Fibers
Researchers apparently have discovered a unique way to help Darwin's finches on the Galápagos Islands fight off the parasitic maggots
threatening their survival, according to a new report
in the journal Current Biology
. While working in the Galápagos, scientists
A Darwin's finch collects treated cotton for its nest
from the University of Utah noticed that the finches often collected cotton and other fibers to weave into their nests. The researchers decided to provide the birds with cotton treated with permethrin — a mild pesticide, commonly used to treat head lice in children, that is safe for birds — hoping the finches would incorporate the fibers in their nests. Finches near the test sites did just that, and their "self-fumigated" nests contained about half as many parasitic maggots — which infest and can kill newly-hatched chicks — compared to nests with untreated cotton. Darwin's finches and other bird species in the Galápagos have suffered steep population declines since the flies showed up in large numbers in the 1990s.
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.
02 May 2014:
Fracking May Induce Quakes at
Greater Distance than Previously Thought
Hydraulic fracturing and underground wastewater disposal may trigger earthquakes at tens of kilometers from the wells in which water is injected — a greater range than previously thought, according to new research from seismologists
. In one case, an earthquake
Fracking injection well in Louisiana
swarm in Oklahoma has been linked to a cluster of fracking injection wells up to 50 kilometers (31 miles) away, Cornell University researchers report. So-called "induced seismicity" — when human activity causes tremors in the earth's crust — is gaining attention as reports of earthquakes within the central and eastern U.S. have increased dramatically over the past few years. The rise coincides with increased hydraulic fracturing for oil and natural gas, and the injection of wastewater in deep disposal wells in many locations, including Colorado, Oklahoma, and Texas. According to the U.S. Geological Survey (USGS), an average rate of 100 earthquakes per year above a magnitude 3.0 occurred in the three years from 2010-2012, compared with an average rate of 21 events per year observed from 1967-2000.