Shading Earth: Delivering Solar Geoengineering Materials to Combat Global Warming May Be Feasible and Affordable

ORIGINAL: ScienceDaily

ScienceDaily (Aug. 29, 2012) — A cost analysis of the technologies needed to transport materials into the stratosphere to reduce the amount of sunlight hitting Earth and therefore reduce the effects of global climate change has shown that they are both feasible and affordable.

A cost analysis of the technologies needed to transport materials into the stratosphere to reduce the amount of sunlight hitting Earth and therefore reduce the effects of global climate change has shown that they are both feasible and affordable. (Credit: © mozZz / Fotolia)

Published August 31, 2012, in IOP Publishing's journal Environmental Research Letters, the study has shown that the basic technology currently exists and could be assembled and implemented in a number of different forms for less than USD $5 billion a year.

Put into context, the cost of reducing carbon dioxide emissions is currently estimated to be between 0.2 and 2.5 per cent of GDP in the year 2030, which is equivalent to roughly USD $200 to $2000 billion.

Solar radiation management (SRM) looks to induce the effects similar to those observed after volcanic eruptions; however, the authors state that it is not a preferred strategy and that such a claim could only be made after the thorough investigation of the implications, risks and costs associated with these issues.

The authors caution that reducing incident sunlight does nothing at all to reduce greenhouse gas concentrations in the atmosphere, nor the resulting increase in the acid content of the oceans. They note that other research has shown that the effects of solar radiation management are not uniform, and would cause different temperature and precipitation changes in different countries.

Co-author of the study, Professor Jay Apt, said: "As economists are beginning to explore the role of several types of geoengineering, it is important that a cost analysis of SRM is carried out. The basic feasibility of SRM with current technology is still being disputed and some political scientists and policy makers are concerned about unilateral action."

In the study, the researchers, from Aurora Flight Sciences, Harvard University and Carnegie Mellon University, performed an engineering cost analysis on six systems capable of delivering 1-5 million metric tonnes of material to altitudes of 18-30 km: 

• existing aircraft,
• a new airplane designed to perform at altitudes up to 30 km,
• a new hybrid airship,
• rockets,
• guns and
• suspended pipes carrying gas or slurry to inject the particles into the atmosphere.

Based on existing research into solar radiation management, the researchers performed their cost analyses for systems that could deliver around one million tonnes of aerosols each year at an altitude between 18 and 25 km and between a latitude range of 30°N and 30°S.

The study concluded that using aircraft is easily within the current capabilities of aerospace engineering, manufacturing and operations. The development of new, specialized aircraft appeared to be the cheapest option, with costs of around $1 to $2 billion a year; existing aircraft would be more expensive as they are not optimized for high altitudes and would need considerable and expensive modifications to do so.

Guns and rockets appeared to be capable of delivering materials at high altitudes but the costs associated with these are much higher than those of airplanes and airships due to their lack of reusability.

Although completely theoretical at this point in time, a large gas pipe, rising to 20 km in the sky and suspended by helium-filled floating platforms, would offer the lowest recurring cost-per-kilogram of particles delivered but the costs of research into the materials required, the development of the pipe and the testing to ensure safety, would be high; the whole system carries a large uncertainty.

Professor Apt continued: "We hope our study will help other scientists looking at more novel methods for dispersing particles and help them to explore methods with increased efficiency and reduced environmental risk."

The researchers make it clear that they have not sought to address the science of aerosols in the stratosphere, nor issues of risk, effectiveness or governance that will add to the costs of solar radiation management geoengineering.

American Meteorological Society revised climate change statement (Video)

ORIGINAL: The Examiner

BY: PAUL HAMAKER

AUGUST 27, 2012

The American Meteorological Society (AMS) released an updated Statement on Climate Change, replacing the 2007 version on August 27, 2012, that will be considered in effect unless revised until August 2017.

The statement is based on a review of the entire body of literature concerning climate change published by AMS members and other over the last five years. The statement is contextually applicable to the United States but is inherently global in nature according to the authors and contributors.

One should bear in mind that the majority of person who offer differing views of climate change are also members of and contributors to the AMS.

According to the researcher's analysis:

Observations show increases in globally averaged air and ocean temperatures, as well as widespread melting of snow and ice and rising globally averaged sea level. Surface temperature data for Earth as a whole, including readings over both land and ocean, show an increase of about 0.8°C (1.4°F) over the period 1901─2010 and about 0.5°C (0.9°F) over the period 1979–2010 (the era for which satellite-based temperature data are routinely available).

five of the emissions scenarios used by the IPCC, compared to the IEA's actual observational CO2 emissions data from fossil fuel consumption. Photo credit: Dana Nuccitelli http://www.skepticalscience.com/graphics.php This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

The amount of rain falling in very heavy precipitation events (the heaviest 1% of all precipitation events) has increased over the last 50 years throughout the U.S. Freezing levels are rising in elevation, with rain occurring more frequently instead of snow at mid-elevations of western mountains.

It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases, including carbon dioxide (CO2), chlorofluorocarbons, methane, and nitrous oxide.

Observations indicate an increase in globally averaged water vapor in the atmosphere in recent decades, at a rate consistent with the response produced by climate models that simulate human-induced increases in greenhouse gases. This increase in water vapor also strengthens the greenhouse effect, amplifying the impact of human-induced increases in other greenhouse gases.

Confidence in the projections is higher for temperature than for other climate elements such as precipitation, and higher at the global and continental scales than for the regional and local scales. The model projections show that the largest warming will occur in northern polar regions, over land areas, and in the winter season, consistent with observed trends.

There is unequivocal evidence that Earth’s lower atmosphere, ocean, and land surface are warming; sea level is rising; and snow cover, mountain glaciers, and Arctic sea ice are shrinking.

The position statement can be read in its entirety here.

Warming Will Unlock Carbon in Forests, Study Warns

ORIGINAL: NYTimes Green Blog

By FELICITY BARRINGER

Will Owens. Franceska Hopkins, the lead author of the study on the release of carbon from soil in forests.

Climate scientists have long been concerned about the possibility that warming temperatures will speed changes on the earth’s surface that will in turn accelerate global warming. The best illustration of such a feedback loop involves the melting of sea ice in the Arctic. The ice reflects solar radiation back into space rather than absorbing it. When it melts, it leaves open water that absorbs the heat rather than reflecting it. The more warm water there is, the more ice melts, and so on.

Now scientists have identified another feedback loop that may be accelerating the loss of carbon dioxide from the topsoil of forests in the United States, contributing to climate change. In a study published online on Monday, researchers at the University of California, Irvine and the Lawrence Berkeley National Laboratory found that the warmer it gets, the more active are the microbes that eat the topsoil and exhale carbon dioxide afterward.

While that finding is not surprising, said the lead author, Francesca Hopkins, a doctoral researcher in the Department of Earth System Science at Irvine, she and her collaborators also found that in warmer temperatures the microbes are better able to digest decades-old carbon stored in the soils. Scientists had previously that the old carbon was inaccessible because it had become fixed in the soil.

The study was published online in the Proceedings of the National Academy of Sciences.

“This has been really hotly debated in the past decade or so,” Ms. Hopkins said in an interview. “Some people think the older soil carbon would decompose more quickly” as temperatures increase, “and some think it wouldn’t decompose at all, because it had stabilized.” The mechanisms by which carbon is stabilized in the soil are poorly understood, although it is clear that some carbon molecules bind to mineral particles in the soil, she said.

But after collecting soils from woodlands in North Carolina and Wisconsin and putting them in mason jars, then storing the jars in incubators at different temperatures, “we saw that the microbes could access some carbon that is at least a decade old,” she said.

The age of the carbon was determined by the isotopes in the carbon dioxide exhaled by the microbes; carbon older than a decade has a distinctive isotope signature. The scientists were able to pinpoint the age of the carbon that had been stored for less than a decade more precisely by measuring a different set of isotopes.

The study reported an eightfold increase in carbon dioxide production when temperatures were increased by 20 degrees Celsius (36 degrees Fahrenheit). This is far in excess of the range of temperature increases predicted to occur by the end of the century under existing climate models. Under the moderate warming scenario predicted by the Intergovernmental Panel on Climate Change, Ms. Hopkins’s experiment indicated that the respiration rates of the microbes — and the amount of carbon-dioxide they exhale — would roughly double by 2100.

The ability to measure the age of the carbon in the soil could be an increasingly useful tool for scientists, although the measurements are still being refined. The components of soil, including decaying leaves, roots and other vegetable matter, store at least twice as much carbon as the chemicals in the atmosphere, according to United Nations climate reports.

The findings of the new study further complicate the dynamics underlying forests’ role in carbon storage. Forests are widely known as repositories of carbon — about 104 billion tons of it worldwide — but the role they will play in a warming world is less understood. If they become carbon emitters rather than carbon sinks as temperatures warm, projections of how fast climate change will occur may have to be adjusted.

Carbon dioxide caused global warming at Ice Age's end, pioneering simulation shows

ORIGINAL: Oak Ridge National Laboratory (ORNL)

Groundbreaking demo proves model to predict climate's future can reproduce its past

Global temperature mirrored and generally lagged behind rising carbon dioxide during Ice Age's deglaciation, pointing to carbon dioxide as the major driver of global warming.

Climate science has an equivalent to the "what came first—the chicken or the egg?" question: What came first, greenhouse gases or global warming? A multi-institutional team led by researchers at Harvard, Oregon State University, and the University of Wisconsin used a global dataset of paleoclimate records and the Jaguar supercomputer at Oak Ridge National Laboratory (ORNL) to find the answer (spoiler alert: carbon dioxide drives warming). The results, published in the April 5 issue of Nature, analyze 15,000 years of climate history. Scientists hope amassing knowledge of the causes of natural global climate change will aid understanding of human-caused climate change.

"We constructed the first-ever record of global temperature spanning the end of the last ice age based on 80 proxy temperature records from around the world," said Jeremy Shakun, a National Oceanic and Atmospheric Administration (NOAA) Climate and Global Change postdoctoral fellow at Harvard and Columbia Universities and first author of the paper. "It's no small task to get at global mean temperature. Even for studies of the present day you need lots of locations, quality-controlled data, careful statistics. For the past 21,000 years, it's even harder. But because the data set is large enough, these proxy data provide a reasonable estimate of global mean temperature."

Proxy records from around the world—derived from ice cores and ocean and lake sediments -- provide estimates of local surface temperature throughout history, and carbon-14 dating indicates when those temperatures occurred. For example, water molecules harboring the oxygen-18 isotope rain out faster than those containing oxygen-16 as an air mass cools, so the ratio of these isotopes in glacial ice layers tells scientists how cold it was when the snow fell. Likewise, the amount of magnesium incorporated into the shells of marine plankton depends on the temperature of the water they live in, and these shells get preserved on the seafloor when they die. The authors combined these local temperature records to produce a reconstruction of global mean temperature. Additionally, samples of ancient atmosphere are trapped as air bubbles in glaciers, providing a direct measure of carbon dioxide levels through time that could be compared to the global temperature record.

Being the first to reconstruct global mean temperatures throughout this time interval allowed the researchers to show what many suspected but none could yet prove: "This is the first paper to definitively show the role carbon dioxide played in helping to end the last ice age," said Shakun, who co-wrote the paper with Peter Clark of Oregon State University. "We found that global temperature mirrored and generally lagged behind rising carbon dioxide during the last deglaciation, which points to carbon dioxide as the major driver of global warming." Prior results based on Antarctic ice cores had indicated that local temperatures in Antarctica started warming before carbon dioxide began rising, which implied that carbon dioxide was a feedback to some other leading driver of warming. The delay of global temperature behind carbon dioxide found in this study, however, shows that the ice-core perspective does not apply to the globe as a whole and instead suggests that carbon dioxide was the primary driver of worldwide warming.

Nature article:http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html

While the geologic record showed a remarkable correlation between carbon dioxide and global temperature, the researchers also turned to state-of-the-art model simulations to further pin down the direction of causation suggested by the temperature lag. Jaguar recently ran approximately 14 million processor hours to simulate the most recent 21,000 years of Earth's climate. Feng He of the University of Wisconsin, Madison, a postdoctoral researcher, plugged the main forcings driving global climate over this time interval into an Intergovernmental Panel on Climate Change (IPCC)-class model called the Community Climate System Model version 3, a global climate model that couples interactions between atmosphere, oceans, lands, and sea ice. The climate science community developed the model with support from the National Science Foundation (NSF), Department of Energy (DOE), and National Aeronautics and Space Administration (NASA) and used many codes developed by university researchers.

"Our model results are the first IPCC-class Coupled General Circulation Model (CGCM) simulation of such a long duration (15,000 years)," said He, who conducted the modeling with Zhengyu Liu of the University of Wisconsin-Madison and Bette Otto-Bliesner of the National Center for Atmospheric Research (NCAR). "This is of particular significance to the climate community because it shows, for the first time, that at least one of the CGCMs used to predict future climate is capable of reproducing both the timing and amplitude of climate evolution seen in the past under realistic climate forcing."

The group ran simulations that used 4.7 million processor hours in 2009, 6.6. million in 2010, and 2.5 million in 2011. The Innovative and Novel Computational Impact on Theory and Experiment program, jointly managed by leadership computing facilities at Argonne and Oak Ridge National Laboratories, awarded the allocations.

Shaun Marcott and Alan Mix of Oregon State University analyzed data, and Andreas Schmittner, also of Oregon State, interpreted links between ocean currents and carbon dioxide. Edouard Bard of Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement provided data and expertise about radiocarbon calibration.

NSF supported this research through its Paleoclimate Program for the Paleovar Project and NCAR. The researchers used resources of the Oak Ridge Leadership Computing Facility, located in the National Center for Computational Sciences at ORNL, which is supported by DOE's Office of Science. The paleoclimate community generated the proxy data sets and provided unpublished results of the DATED Project on retreat history of the Eurasian ice sheets. The NOAA NGDC and PANGAEA databases were also essential to this work.

Plot twist: the 'bipolar seesaw'

As the dominant theory goes, the variation of Earth's orbit around the sun is responsible for the growth and deterioration of glaciers because it changes insolation, or solar radiation reaching and warming an area. About 21,000 years ago the orbit of the Earth was slightly predisposed to warmer summers in the Northern Hemisphere, and the planet experienced a general warming.

Next comes a plot twist. Geologic data show that about 19,000 years ago, Northern Hemisphere glaciers began to melt, and sea levels rose. Melting glaciers dumped so much freshwater into the ocean that it slowed a system of currents that transports heat throughout the world. Called the Atlantic Meridional Overturning Circulation (AMOC), this ocean conveyor belt is particularly important in the Atlantic where it flows northward across the equator, stealing Southern Hemisphere heat and exporting it to the Northern Hemisphere. The AMOC then sinks in the North Atlantic and returns southward in the deep ocean. A large pulse of glacial meltwater, however, can place a freshwater lid over the North Atlantic and halt this sinking, backing up the entire conveyor belt.

The simulation showed weakening of the AMOC due to the increase in glacial melt beginning about 19,000 years ago, which decreased ocean heat transport, keeping heat in the Southern Hemisphere and cooling the Northern Hemisphere. Other studies suggest this southern warming caused sea ice to retreat and shifted winds around the Southern Ocean, uncorking carbon dioxide that had previously been stored in the deep ocean and venting it to the atmosphere around 17,500 years ago. This rise in carbon dioxide then initiated worldwide warming.

The seesawing of heat between the hemispheres due to the AMOC shutdown explains why Southern Hemisphere warming led the rise in carbon dioxide while Northern Hemisphere temperatures lagged behind and reconciles these patterns with the key role played by carbon dioxide in driving global mean warming. "Differences in the deglacial temperature evolution of the Northern and Southern Hemispheres can largely be explained by variations in the strength of the Atlantic Meridional Overturning Circulation," said He.

Before the team's groundbreaking efforts, researchers could only simulate single time slices of Earth's climate. Just as multiple images are stitched together to make an animation, speedy petascale supercomputers, capable of executing a quadrillion calculations each second, enable stitching together of multiple time slices to produce a continuous simulation. Liu, Otto-Bliesner, and He's group was the first to continuously capture climate from 21,000 years ago to the present day so that scientists could compare the relationship of carbon dioxide and global mean temperature over time. The Nature article covers events up to about 6,000 years ago. The group has since extended the simulation through the present day.

"Climate model output housed at Oak Ridge is currently in the hundreds of terabytes [trillion bytes] and will soon exceed a petabyte, so you need a large facility just to accommodate the large data output," said He. "Right now the climate model output is a top consumer of data storage in Oak Ridge. Also, [continuous simulations] definitely cannot be performed at other sites because the system needs to be quite consistent. This simulation has been run continuously for more than 3 years. Each simulation [step] depends on what happened earlier."

To understand the relevance of the study's finding to today, it is worth considering that carbon dioxide concentrations rose from 185 parts per million (ppm) to 260 ppm over the approximately 10,000 years during which the last ice age ended. In just the past two centuries, human activity has increased concentrations by about the same amount, reaching a carbon dioxide concentration of 392 ppm in 2011—higher than at any time in at least the last 800,000 years.

The work builds on a continuous simulation by Liu and colleagues of Earth's climate between 21,000 and 14,000 years ago, reported in a 2009 Science article detailing the first continuous simulation of climate change during Earth's most recent period of natural global warming. Using ORNL's Cray X1E supercomputer named Phoenix and the even faster Cray XT system called Jaguar, the scientists used nearly a million processor hours in 2008 to run one-third of their simulation, from 21,000 years ago (the most recent glacial maximum) to 14,000 years ago (the most recent major period of natural global warming). The effort validated the ability to simulate large climate changes in the past and is critical for assessing future projections of changes, such as the fate of ocean circulation in the face of continued glacial melting in Greenland and Antarctica.— Dawn Levy, April 4, 2012

Informe especial sobre la Gestión de riesgos de fenómenos extremos y desastres para fomentar la adaptación al cambio climático (SREX)

ORIGINAL: IPCC

"...puede afirmarse con un alto grado de confianza que tanto las temperaturas diarias máximas como las mínimas han aumentado a escala mundial, debido al aumento de los gases de efecto invernadero..."

"...Con respecto al futuro, la Evaluación concluye que  es virtualmente cierto que a escala mundial los días cálidos lo serán aún más, y con mayor frecuencia..."

BOLETÍN DE PRENSA 

Kampala, 18 de noviembre de 2011  - 

El Resumen para responsables de políticas del Informe especial sobre la Gestión de riesgos de fenómenos extremos y desastres para fomentar la adaptación al cambio climático  (SREX) fue aprobado hoy por los Gobiernos miembros del Grupo Intergubernamental de Expertos sobre el Cambio Climático (IPCC).

El Resumen para responsables de políticas del SREX  puede consultarse en http://ipcc-wg2.gov/SREX y www.ipcc.ch.

Rajendra Pachauri, Presidente del IPCC, señaló hoy que "este Resumen para responsables de políticas ayuda a entender la manera en que la gestión de riesgos de desastre y la adaptación podrían ayudar a las comunidades vulnerables a afrontar mejor el cambio del clima en un mundo de desigualdades".

"Subraya también la complejidad y diversidad de los factores que configuran la vulnerabilidad humana frente a los extremos: por qué en algunos países y comunidades pueden convertirse en desastres, mientras que en otros pueden ser menos severos", añadió.

Qin Dahe, Copresidente del Grupo de trabajo I del IPCC, que junto con el Grupo de trabajo II fue responsable de elaborar y preparar el informe, manifestó que "puede afirmarse con un alto grado de confianza que tanto las temperaturas diarias máximas como las mínimas han aumentado a escala mundial, debido al aumento de los gases de efecto invernadero".

“Se están observando en ciertas regiones variaciones de otros fenómenos extremos, como una mayor intensidad y duración de las sequías, pero la Evaluación les asigna un nivel de verosimilitud medio, debido a la falta de observaciones directas y de concordancia entre los estudios científicos disponibles. Se considera que las tendencias en intensidad, frecuencia o duración de los ciclones tropicales a largo plazo tienen una verosimilitud baja", agregó.

Con respecto al futuro, la Evaluación concluye que  es virtualmente cierto que a escala mundial los días cálidos lo serán aún más, y con mayor frecuencia. "En el escenario de emisiones elevadas, es probable que la frecuencia de días cálidos aumente en un factor de 10 en la mayoría de las regiones del mundo", señaló el otro Copresidente del Grupo de trabajo I, Thomas Stocker. “Las precipitaciones intensas serán también más frecuentes, y en los ciclones tropicales la velocidad del viento aumentará, mientras que su número se mantendrá probablemente constante o disminuirá".

“No obstante, hay muchas posibilidades de reducir el riesgo. Algunas de esas opciones han sido ya adoptadas, pero muchas otras no. Las mejores opciones pueden ser beneficiosas en muchas de las variantes del cambio climático", declaró Vicente Barros, Copresidente del Grupo de trabajo II.