Peru’s indigenous people call for protections against environmental threats

As delegates from around the world gather in Lima, Peru, to work on a framework on climate change, thousands of Peruvians flocked to the capital to demand better protection for their lands and cultures. As part of our Culture at Risk series, Jeffrey Brown reports from Lima on the struggle to balance the protection of remote indigenous communities with industry and growth.
Credit: Jeffrey Brown

GWEN IFILL: International delegates have gathered for climate change talks in Lima, Peru, this week, hoping to build the framework for a plan to cut the world’s heat-trapping gas emissions.

Secretary of State John Kerry arrived there today to help with that new accord. But, for many Peruvians, the focus is local, as mining and timber operations encroach into once pristine areas inhabited by indigenous tribes.

Jeffrey Brown is in Lima, and has this report, part of his series Culture at Risk.

JEFFREY BROWN: There were dancers and drummers, banners and chants, traditional clothing of all kinds, a march of thousands, many of them tribal people, that shut down part of downtown Lima for several hours, demanding better protection of their lands and their cultures. They came from near and far, some very far.

This group from the Ucayali region in Eastern Peru had traveled for several days, by boat, plane, and bus, to get here from their remote homes.

Grimaldo Villacorta heads the group.

GRIMALDO VILLACORTA (through interpreter): For us, as an indigenous population, it’s important to be here, because we want to stop climate change. We used to have regular seasons, summer and winter, during which we planted our seeds. But now, with the climate changing, we can work the land, but sometimes we cannot plant seeds. There is no production.

JEFFREY BROWN: This demonstration was set up as a kind of counterpoint to the official climate talks going on across town. The idea is to raise awareness about the increasing and increasingly violent encroachment on tribal lands in Peru and elsewhere around the globe.

Throughout the crowd, portraits of one of the martyrs of this movement, Edwin Chota, a Peruvian environmental activist from the Ashaninka Indian tribe who’d spent years fighting illegal logging on his community’s lands.

In September, Chota and three others from the village of Saweto were shot and killed near the Brazilian border, in the vast Amazon Basin that’s home to about half of Peru’s more than 1,500 indigenous communities, with some 300,000 people. Chota had spoken of threats he received as he fought to gain official title to his lands and keep loggers at bay.

EDWIN CHOTA, Environmental Activist (through interpreter): They are loggers. They have arms. They have everything. And they are never going to pay attention to us. So we need the support of government institutions to protect the region at the border.

JEFFREY BROWN: Chota’s remains were found by a river near his home. Two loggers have been charged with his murder.

That and other incidents led the advocacy group Global Witness to declare Peru one of the world’s most dangerous countries for environmental activists. And by all accounts, illegal logging, mining, and drug trafficking have been on the rise in this area. The World Bank estimates, for example, that some 80 percent of Peru’s timber exports were cut without a permit.

In Lima this week, Patricia Balbuena, the vice culture minister who overseas indigenous relations, said the government is working to resolve land ownership disputes, but that administrations past and present have struggled to ensure legal rights and safety in these distant communities.

PATRICIA BALBUENA, Vice Minister of Intercultural Affairs, Peru (through interpreter): These are remote areas with very little government presence because of geographical barriers. For example, from the capital of Pucallpa region to the community of Saweto, it takes six to eight days by boat.

That is why the most important issue is to assure the government’s presence, not only in terms of a military or police presence, but also in what a government should provide to its indigenous populations: health, education, social services, and security.

JEFFREY BROWN: Encroachment deep into Amazon forests may also be behind scenes like this, as previously isolated or uncontacted tribes come into the open.

Last year, more than 100 members of the Mashco-Piro tribe appeared at a river in Southeast Peru.

Anthropologist Beatriz Huertas studies groups like this who’ve chosen to live apart from civilization. She thinks she knows why more are now making contact.

BEATRIZ HUERTAS, Anthropologist (through interpreter): I think that, first of all, it’s owed to the great pressures on their lands and natural resources, and that those are forcing these isolated peoples to alter their ways and are leading to their displacement.

JEFFREY BROWN: There are more such tribes than you might think. The advocacy group Survival International estimates there are 15 in Peru alone, and at least 100 around the globe.

The highest concentration is here in the Amazon. Citing the threat of contagious disease and other problems that have decimated previously uncontacted tribes, Beatriz Huertas says the government needs to take immediate action.

BEATRIZ HUERTAS (through interpreter): To protect them, it’s necessary to officially recognize their lands and to establish a series of protection mechanisms to guarantee their lives, their health and the right of these populations to decide for themselves what lives they want to live.

JEFFREY BROWN: I asked Vice Minister Balbuena the overarching question, how Peru can foster investment and growth, while also protecting vulnerable people and cultures.

PATRICIA BALBUENA (through interpreter): I think we always feel we need to do more. I think the demands of the indigenous peoples require us to act faster. And we can’t advance a peaceful society if we don’t find a balancing point between growth on the one hand and respect and protection of rights on the other.

JEFFREY BROWN: Achieving a balance has also, of course, been on the minds of attendees at the climate change summit this week in Lima. After years of setbacks and sidesteps, the goal here is for nations to commit, or at least commit to committing, to specific domestic emissions cuts.

The grand hope, a new global treaty to be signed at next year’s meeting in Paris. The effort got a boost last month with an agreement between China and the U.S., the world’s largest economies and polluters, to limit their greenhouse gas emissions over the next two decades.

In pavilions open to the public, Peruvians of all ages took in exhibitions that explained the tangible effects of climate change. There, conference attendee Chris Field told me he felt encouraged by what he’d heard so far at the meetings, but that huge challenges remained.

CHRIS FIELD, Carnegie Institution: The big challenge is ambition of mitigation, how much we decrease the emissions of heat-trapping gases, ambition of adaption, how much we invest in helping people cope with the climate changes that can’t be avoided, and how tightly those two things should be connected.

JEFFREY BROWN: And getting — and getting individual countries to actually make commitments.

CHRIS FIELD: Well, what you find is that, kind of constitutionally, there’s a difference between the perspective that the developed countries take, which is really focused on mitigation aspects, and the developing countries, who want to see much more of a interlinkage between investments in decreasing amounts of heat-trapping gases and increasing investments in helping people cope.

JEFFREY BROWN: Case in point, of course, is the host country itself, which faces many long-term environmental threats and, as tribal demonstrators shouted in the streets, immediate, urgent ones that demand answers and actions.

I’m Jeffrey Brown reporting from Lima for the “PBS NewsHour.”

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Better dam planning strategies

This is a map showing combined effect of current and future dams. Credit: McGill University

When dams are built they have an impact not only on the flow of water in the river, but also on the people who live downstream and on the surrounding ecosystems. By placing data from close to 6,500 existing large dams on a highly precise map of the world's rivers, an international team led by McGill University researchers has created a new method to estimate the global impacts of dams on river flow and fragmentation.

Among their findings, published online today in Environmental Research Letters: 48% of the world's river volume is moderately or severely affected by dams today -- and that figure would nearly double if all dams planned or under construction are completed in the future.

"Over the past 60 years, a myriad of dams have been built either to provide hydroelectric power, or for irrigation purposes, or as flood protection," says Bernhard Lehner, a professor in McGill University's Department of Geography and the research director of the project. "The construction of large dams then slowed down for the last 20 years as we became more aware of their negative effects on people and ecosystems. But now, with fears about how climate change may affect water flows in the future, the goal of creating reservoirs is once more appealing, and dam construction is on the rise."

The new research was made possible by the team's development of a global river map with unprecedented resolution and detail, showing all waterways of the world from small creeks to the largest of rivers, accounting for a cumulative river length of 48.3 million km -- and by a new map of future dam locations assembled by colleagues at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Berlin.

The key components of the team's dam assessment method are two indices that describe river fragmentation and river regulation.

The river fragmentation index (RFI) is a measure of the way that a river's natural flow path (also known as its connectivity) has been disrupted by the creation of dams or by barriers that allow for the transfer of water between basins or towards irrigation areas, for example.

The river regulation index (RRI) is a measure of the proportion of the river water that can be stored in reservoirs, and thus affects the natural fluctuation and properties of river flow downstream.

By combining these two indices, the researchers have arrived at a way of assessing the impact of any existing or planned dam. So, for example, the Danube is severely impacted by fragmentation effects but is relatively weakly affected in terms of flow regulation due to many dams with relatively small reservoirs. The Murray-Darling basin in southern Australia, by contrast, is only weakly affected by fragmentation, but is heavily impacted by flow regulation, due to fewer but larger reservoirs.

"Not all dams are equal," says Günther Grill, a postdoctoral fellow in McGill University's Department of Geography and the lead author on the paper. "Our research assumes that it is not only the size of a dam but also where it is placed along the river that makes a difference. So depending on whether a dam is high up in the mountain headwaters or further down close to the delta, if it is on the main stem of the river or on a small tributary, all of these factors will have varying effects on the rivers and their surrounding ecosystems."

Researchers at the University of Minnesota's Institute on the Environment and the University of Wisconsin's Center for Limnology also contributed to the study.

Some dam and river facts:

There are 6,374 large dams already in existence and 3,377 planned or proposed large dams to be built by 2030.

Currently 48% of the world's river volume is moderately or severely affected by either flow regulation or fragmentation or both.

Assuming that all the dams that are planned or under construction are completed, this number would almost double to 93%, largely due to multiple dams being planned for major tributaries in the Amazon Basin.

Other large rivers that are currently rather free-flowing but on which large dams are planned are the Mekong River in Southeast Asia and the Amur River in Russia.

Source: McGill University

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Climate change not responsible for altering forest tree composition, experts say

Eastern US forest canopy. Credit: Mary Ann Fajvan, West Virginia University, Bugwood.org

Change in disturbance regimes -- rather than a change in climate -- is largely responsible for altering the composition of Eastern forests, according to a researcher in Penn State's College of Agricultural Sciences.

Forests in the Eastern United States remain in a state of "disequilibrium" stemming from the clear-cutting and large-scale burning that occurred in the late 1800s and early 1900s, contends Marc Abrams, professor of forest ecology and physiology.

Moreover, Abrams noted, since about 1930 -- during the Smokey Bear era -- aggressive forest-fire suppression has had a far greater influence on shifts in dominant tree species than minor differences in temperature.

"Looking at the historical development of Eastern forests, the results of the change in types of disturbances -- both natural and man-caused -- are much more significant than any change in climate," said Abrams, who is the Steimer Professor of Agriculture in the Department of Ecosystem Science and Management.

"Over the last 50 years, most environmental science has focused on the impact of climate change. In some systems, however, climate change impacts have not been as profound as in others. This includes the forest composition of the eastern U.S."

To determine how forest tree species have responded to changes in disturbance regimes, temperature and precipitation over long periods of time, Abrams collaborated with Gregory Nowacki, a scientist with the U.S. Department of Agriculture Forest Service office in Milwaukee, on a study of the tolerance and sensitivity of trees to various factors.

"Many ecological phenomena combine to direct vegetation trends over time, with climate and disturbance playing prominent roles," said Nowacki, who received his Ph.D under Abrams. "To help decipher their relative importance during Euro-American times, we employed a unique approach whereby tree species/genera were partitioned into temperature, shade tolerance and pyrogenicity classes and applied to comparative tree-census data."

The researchers compared presettlement -- original land survey data -- and current vegetation conditions in the eastern United States. Early tree surveys chronicle the westward progression of European land acquisition, with some dating back to the 1600s along the East Coast.

In the research, published online in Global Change Biology, researchers analyzed 190 datasets to determine the relative impacts of climate versus altered disturbance regimes for various biomes across the eastern United States. Because the Euro-American period from 1500 to today spans two major climatic periods -- from the Little Ice Age to the current Anthropocene -- the researchers expected vegetation changes consistent with warming.

"In most cases, however, European disturbance overrode regional climate change," Abrams said. "To the north, intensive and expansive early European disturbance resulted in the ubiquitous loss of conifers and large increases of Acer (maple), Populus (poplar) and Quercus (oak) in northern hardwoods, whereas to the south, these disturbances perpetuated the dominance of oak in central hardwoods."

Maple increases and associated mesophication -- the forest growing increasingly dense, cool, shady and moist in the absence of regular fire -- in oak-pine systems were delayed until mid-20th century fire suppression. This led to significant warm-to-cool shifts in temperature in which cool-adapted sugar maple increased and caused temperature-neutral changes in which warm-adapted red maple increased.

"In both cases, these shifts were attributed to fire suppression rather than climate change," Abrams said. "Because mesophication is ongoing, eastern U.S. forests formed during the catastrophic disturbance era followed by fire suppression will remain in climate disequilibrium into the foreseeable future."

Overall, he concluded, the results of the study suggest that altered disturbance regimes rather than climate had the greatest influence on vegetation composition and dynamics in the eastern United States over multiple centuries.

"Land-use change often trumped or negated the impacts of warming climate, and this needs greater recognition in climate change discussions, scenarios and model interpretations," he said.

Source: Penn State

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Coexist or perish, new wildfire analysis says: Changing wildfire paradigm from fighting to coexistence

The lightning-sparked Castle Rock Fire burned nearly 50,000 acres in 2007 in the Sawtooth National Forest and adjacent state and private lands surrounding Ketchum, Idaho, in the Smoky Mountains region of the Rocky Mountain range. Credit: Kari Geer, courtesy of the National Interagency Fire Center

Many fire scientists have tried to get Smokey the Bear to hang up his "prevention" motto in favor of tools like thinning and prescribed burns, which can manage the severity of wildfires while allowing them to play their natural role in certain ecosystems.

But a new international research review led by the University of California, Berkeley, says the debate over fuel-reduction techniques is only a small part of a much larger fire problem that will make society increasingly vulnerable to catastrophic losses unless it changes its fundamental approach from fighting fire to coexisting with fire as a natural process.

The paper, "Learning to Coexist with Wildfire," to be published in the Nov. 6 issue of the journal Nature, examines research findings from three continents and from both the natural and social sciences. The authors conclude that government-sponsored firefighting and land-use policies actually encourage development on inherently hazardous landscapes, amplifying human losses over time.

"We don't try to 'fight' earthquakes -- we anticipate them in the way we plan communities, build buildings and prepare for emergencies. We don't think that way about fire, but our review indicates that we should," said lead author Max Moritz, Cooperative Extension specialist in fire at UC Berkeley's College of Natural Resources. "Human losses will only be mitigated when land-use planning takes fire hazards into account in the same manner as other natural hazards, like floods, hurricanes and earthquakes."

The analysis looked at different kinds of natural fires, what drives them in various ecosystems, the ways public response to fire can differ, and the critical interface zones between built communities and natural landscapes. The authors found infinite variations on how these factors can come together.

"It quickly became clear that generic one-size-fits-all solutions to wildfire problems do not exist," Moritz said. "Fuel reduction may be a useful strategy for specific places, like California's dry conifer forests, but when we zoomed out and looked at fire-prone regions throughout the Western United States, Australia and the Mediterranean Basin, we realized that over vast parts of the world, a much more nuanced strategy of planning for coexistence with fire is needed."

Planning for co-existence

If humans choose to live in fire-prone regions, fire must be managed on par with other naturally occurring hazards, the authors argue, and research must seek to understand what factors and outcomes we can and cannot affect.

One common tool is applicable to the vast array of ecological and social science interactions at the critical wildfire/urban interface: more effective land-use planning, along with the regulations that guide it.

The authors recommend prioritizing location-specific approaches to improve development and safety in fire-prone areas, including:

Adopting new land-use regulations and zoning guidelines that restrict development in the most fire-prone areas;

Updating building codes, such as requiring fire-resistant construction to match local hazard levels and encouraging retrofits to existing ignition-prone homes;

Implementing locally appropriate vegetation management strategies around structures and neighborhoods;

Evaluating evacuation planning and warning systems, including understanding situations in which mandatory evacuations are or are not effective;

Developing household and community plans for how to survive stay-and-defend situations; and

Developing better maps of fire hazards, ecosystem services and climate change effects to assess trade-offs between development and hazard.

As an example of positive steps, the report cites new fire danger mapping efforts, including an existing fire hazard severity zone map that guides building codes in California. Produced by the state's Department of Forestry and Fire Protection, the current map does not explicitly incorporate locally varying wind patterns, which influence the worst fire-related losses of homes and lives, but future iterations will include these data.

Fire ecology and climate

The authors underscore that wildfires are a natural part of many ecosystems and can have a positive long-term influence on the landscape, despite people labeling them as "disasters." They can stimulate vegetation regeneration, promote a diversity of vegetation types, provide habitat for many species and sustain other ecosystem services, such as nutrient cycling.

Around the world, the numbers, sizes, and intensities of fires vary greatly. In some ecosystems, big, severe wildfires are natural events and more climate-driven -- by drought or high winds -- so fuel reduction is not a very effective tool in these locations. By contrast, many ecosystems that would naturally experience frequent lower-severity fires may respond to vegetation management aimed at both reducing fire hazard to humans and restoring crucial ecosystem processes. But, the authors agree, where fuel reduction is an appropriate goal, it would ideally be achieved by letting wildfires do their job.

A changing climate will complicate management strategies.

"How should future fire patterns compare to this historical variability? That's the big question," Moritz said.

Describing wildfire as "one of the most basic and ongoing natural processes on Earth," the authors call for a paradigm shift in the way society interacts with it, changing to an approach that achieves long-term, sustainable coexistence that benefits the planet's ecosystems on the landscape scale, while minimizing catastrophic losses on the human scale.

"A different view of wildfire is urgently needed," said Moritz. "We must accept wildfire as a crucial and inevitable natural process on many landscapes. There is no alternative. The path we are on will lead to a deepening of our fire-related problems worldwide, which will only become worse as the climate changes."

Source: University of California - Berkeley

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Hydraulic fracturing linked to earthquakes in Ohio

Seismograph (stock image). Hydraulic fracturing triggered a series of small earthquakes in 2013 on a previously unmapped fault in Harrison County, Ohio, according to a study. Credit: © hakandogu / Fotolia

Hydraulic fracturing triggered a series of small earthquakes in 2013 on a previously unmapped fault in Harrison County, Ohio, according to a study published in the journal Seismological Research Letters (SRL).

Nearly 400 small earthquakes occurred between Oct. 1 and Dec. 13, 2013, including 10 "positive" magnitude earthquake, none of which were reported felt by the public. The 10 positive magnitude earthquakes, which ranged from magnitude 1.7 to 2.2, occurred between Oct. 2 and 19, coinciding with hydraulic fracturing operations at nearby wells.

This series of earthquakes is the first known instance of seismicity in the area.
Hydraulic fracturing, or fracking, is a method for extracting gas and oil from shale rock by injecting a high-pressure water mixture directed at the rock to release the gas inside. The process of hydraulic fracturing involves injecting water, sand and chemicals into the rock under high pressure to create cracks. The process of cracking rocks results in micro-earthquakes. Hydraulic fracturing usually creates only small earthquakes, ones that have magnitude in the range of negative 3 (−3) to negative 1 (-1).

"Hydraulic fracturing has the potential to trigger earthquakes, and in this case, small ones that could not be felt, however the earthquakes were three orders of magnitude larger than normally expected," said Paul Friberg, a seismologist with Instrumental Software Technologies, Inc. (ISTI) and a co-author of the study.

The earthquakes revealed an east-west trending fault that lies in the basement formation at approximately two miles deep and directly below the three horizontal gas wells. The EarthScope Transportable Array Network Facility identified the first earthquakes on Oct. 2, 2013, locating them south of Clendening Lake near the town of Uhrichsville, Ohio. A subsequent analysis identified 190 earthquakes during a 39-hour period on Oct. 1 and 2, just hours after hydraulic fracturing began on one of the wells.

The micro-seismicity varied, corresponding with the fracturing activity at the wells. The timing of the earthquakes, along with their tight linear clustering and similar waveform signals, suggest a unique source for the cause of the earthquakes -- the hydraulic fracturing operation. The fracturing likely triggered slip on a pre-existing fault, though one that is located below the formation expected to confine the fracturing, according to the authors.

"As hydraulic fracturing operations explore new regions, more seismic monitoring will be needed since many faults remain unmapped." Friberg co-authored the paper with Ilya Dricker, also with ISTI, and Glenda Besana-Ostman originally with Ohio Department of Natural Resources, and now with the Bureau of Reclamation at the U.S. Department of Interior.

Source: Seismological Society of America

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Fracking: Gas leaks from faulty wells linked to contamination in some groundwater

As researchers study hydraulic fracturing, a team led by Thomas Darrah at The Ohio State University has identified a key source of groundwater contamination (labeled 5, center right) caused by faulty well casings.
Credit: Image courtesy of Thomas Darrah, The Ohio State University

A study has pinpointed the likely source of most natural gas contamination in drinking-water wells associated with hydraulic fracturing, and it's not the source many people may have feared.

What's more, the problem may be fixable: improved construction standards for cement well linings and casings at hydraulic fracturing sites.

A team led by a researcher at The Ohio State University and composed of researchers at Duke, Stanford, Dartmouth, and the University of Rochester devised a new method of geochemical forensics to trace how methane migrates under the earth. The study identified eight clusters of contaminated drinking-water wells in Pennsylvania and Texas.

Most important among their findings, published this week in the Proceedings of the National Academy of Sciences, is that neither horizontal drilling nor hydraulic fracturing of shale deposits seems to have caused any of the natural gas contamination.

"There is no question that in many instances elevated levels of natural gas are naturally occurring, but in a subset of cases, there is also clear evidence that there were human causes for the contamination," said study leader Thomas Darrah, assistant professor of earth sciences at Ohio State. "However our data suggests that where contamination occurs, it was caused by poor casing and cementing in the wells," Darrah said.

In hydraulic fracturing, water is pumped underground to break up shale at a depth far below the water table, he explained. The long vertical pipes that carry the resulting gas upward are encircled in cement to keep the natural gas from leaking out along the well. The study suggests that natural gas that has leaked into aquifers is the result of failures in the cement used in the well.

"Many of the leaks probably occur when natural gas travels up the outside of the borehole, potentially even thousands of feet, and is released directly into drinking-water aquifers" said Robert Poreda, professor of geochemistry at the University of Rochester.

"These results appear to rule out the migration of methane up into drinking water aquifers from depth because of horizontal drilling or hydraulic fracturing, as some people feared," said Avner Vengosh, professor of geochemistry and water quality at Duke.

"This is relatively good news because it means that most of the issues we have identified can potentially be avoided by future improvements in well integrity," Darrah said.

"In some cases homeowner's water has been harmed by drilling," said Robert B. Jackson, professor of environmental and earth sciences at Stanford and Duke. "In Texas, we even saw two homes go from clean to contaminated after our sampling began."

The method that the researchers used to track the source of methane contamination relies on the basic physics of the noble gases (which happen to leak out along with the methane). Noble gases such as helium and neon are so called because they don't react much with other chemicals, although they mix with natural gas and can be transported with it.

That means that when they are released underground, they can flow long distances without getting waylaid by microbial activity or chemical reactions along the way. The only important variable is the atomic mass, which determines how the ratios of noble gases change as they tag along with migrating natural gas. These properties allow the researchers to determine the source of fugitive methane and the mechanism by which it was transported into drinking water aquifers.

The researchers were able to distinguish between the signatures of naturally occurring methane and stray gas contamination from shale gas drill sites overlying the Marcellus shale in Pennsylvania and the Barnett shale in Texas.

The researchers sampled water from the sites in 2012 and 2013. Sampling sites included wells where contamination had been debated previously; wells known to have naturally high level of methane and salts, which tend to co-occur in areas overlying shale gas deposits; and wells located both within and beyond a one-kilometer distance from drill sites.

As hydraulic fracturing starts to develop around the globe, including countries South Africa, Argentina, China, Poland, Scotland, and Ireland, Darrah and his colleagues are continuing their work in the United States and internationally. And, since the method that the researchers employed relies on the basic physics of the noble gases, it can be employed anywhere. Their hope is that their findings can help highlight the necessity to improve well integrity.

Source: Ohio State University

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Geoengineering could disrupt rainfall patterns

Volcanic eruptions, such as the one of the Karymsky volcano (Russia) in 2004, release sulphur dioxide to the atmosphere, which has a cooling effect. Geoengineering an ‘artificial volcano’ to mimic this release has been proposed as a solution to global warming.

A geoengineering solution to climate change could lead to significant rainfall reduction in Europe and North America, a team of European scientists concludes. The researchers studied how models of Earth in a warm, CO2-rich world respond to an artificial reduction in the amount of sunlight reaching the planet's surface.

The study is published June 6 in Earth System Dynamics, an Open Access journal of the European Geosciences Union (EGU).

Tackling climate change by reducing the solar radiation reaching our planet using climate engineering, known also as geoengineering, could result in undesirable effects for Earth and humankind. In particular, the work by the team of German, Norwegian, French, and UK scientists shows that disruption of global and regional rainfall patterns is likely in a geoengineered climate.

"Climate engineering cannot be seen as a substitute for a policy pathway of mitigating climate change through the reduction of greenhouse gas emissions," they conclude in the paper.

Geoengineering techniques to reduce the amount of solar radiation reaching Earth's surface range from mimicking the effects of large volcanic eruptions by releasing sulphur dioxide into the atmosphere to deploying giant mirrors in space. Scientists have proposed these sunlight-reflecting solutions as last-ditch attempts to halt global warming.

But what would such an engineered climate be like?
To answer this question, the researchers studied how four Earth models respond to climate engineering under a specific scenario. This hypothetical scenario assumes a world with a CO2 concentration that is four times higher than preindustrial levels, but where the extra heat caused by such an increase is balanced by a reduction of radiation we receive from the Sun.
"A quadrupling of CO2 is at the upper end, but still in the range of what is considered possible at the end of the 21st century," says Hauke Schmidt, researcher at the Max Planck Institute for Meteorology in Germany and lead author of the paper.

Under the scenario studied, rainfall strongly decreases -- by about 15 percent (some 100 millimetres of rain per year) of preindustrial precipitation values -- in large areas of North America and northern Eurasia. Over central South America, all models show a decrease in rainfall that reaches more than 20 percent in parts of the Amazon region. Other tropical regions see similar changes, both negative and positive. Overall, global rainfall is reduced by about five percent on average in all four models studied.

"The impacts of these changes are yet to be addressed, but the main message is that the climate produced by geoengineering is different to any earlier climate even if the global mean temperature of an earlier climate might be reproduced," says Schmidt.

The authors note that the scenario studied is not intended to be realistic for a potential future application of climate engineering. But the experiment allows the researchers to clearly identify and compare basic responses of Earth's climate to geoengineering, laying the groundwork for more detailed future studies.

"This study is the first clean comparison of different models following a strict simulation protocol, allowing us to estimate the robustness of the results. Additionally we are using the newest breed of climate models, the ones that will provide results for the Fifth IPCC [Intergovernmental Panel on Climate Change] Report," explains Schmidt.

The scientists used climate models developed by the UK Met Office's Hadley Centre, the Institut Pierre Simon Laplace in France, and the Max Planck Institute in Germany. Norwegian scientists developed the fourth Earth model used.


Source: European Geosciences Union

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The Hydraulic fracturing linked to earthquakes in Ohio

Seismograph (stock image). Hydraulic fracturing triggered a series of small earthquakes in 2013 on a previously unmapped fault in Harrison County, Ohio, according to a study. Credit: © hakandogu / Fotolia

Hydraulic fracturing triggered a series of small earthquakes in 2013 on a previously unmapped fault in Harrison County, Ohio, according to a study published in the journal Seismological Research Letters (SRL).

Nearly 400 small earthquakes occurred between Oct. 1 and Dec. 13, 2013, including 10 "positive" magnitude earthquake, none of which were reported felt by the public. The 10 positive magnitude earthquakes, which ranged from magnitude 1.7 to 2.2, occurred between Oct. 2 and 19, coinciding with hydraulic fracturing operations at nearby wells.

This series of earthquakes is the first known instance of seismicity in the area.
Hydraulic fracturing, or fracking, is a method for extracting gas and oil from shale rock by injecting a high-pressure water mixture directed at the rock to release the gas inside. The process of hydraulic fracturing involves injecting water, sand and chemicals into the rock under high pressure to create cracks. The process of cracking rocks results in micro-earthquakes. Hydraulic fracturing usually creates only small earthquakes, ones that have magnitude in the range of negative 3 (−3) to negative 1 (-1).
"Hydraulic fracturing has the potential to trigger earthquakes, and in this case, small ones that could not be felt, however the earthquakes were three orders of magnitude larger than normally expected," said Paul Friberg, a seismologist with Instrumental Software Technologies, Inc. (ISTI) and a co-author of the study.

The earthquakes revealed an east-west trending fault that lies in the basement formation at approximately two miles deep and directly below the three horizontal gas wells. The EarthScope Transportable Array Network Facility identified the first earthquakes on Oct. 2, 2013, locating them south of Clendening Lake near the town of Uhrichsville, Ohio. A subsequent analysis identified 190 earthquakes during a 39-hour period on Oct. 1 and 2, just hours after hydraulic fracturing began on one of the wells.

The micro-seismicity varied, corresponding with the fracturing activity at the wells. The timing of the earthquakes, along with their tight linear clustering and similar waveform signals, suggest a unique source for the cause of the earthquakes -- the hydraulic fracturing operation. The fracturing likely triggered slip on a pre-existing fault, though one that is located below the formation expected to confine the fracturing, according to the authors.

"As hydraulic fracturing operations explore new regions, more seismic monitoring will be needed since many faults remain unmapped." Friberg co-authored the paper with Ilya Dricker, also with ISTI, and Glenda Besana-Ostman originally with Ohio Department of Natural Resources, and now with the Bureau of Reclamation at the U.S. Department of Interior.

Source: Seismological Society of America

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