Global Precipitation Linked to Global Warming

The rain in Spain may lie mainly on the plain, but the location and intensity of that rain is changing not only in Spain but around the globe.

A new study by Lawrence Livermore National Laboratory scientists shows that observed changes in global (ocean and land) precipitation are directly affected by human activities and cannot be explained by natural variability alone. The research appears in the Nov. 11 online edition of the Proceedings of the National Academy of Sciences.

Emissions of heat-trapping and ozone-depleting gases affect the distribution of precipitation through two mechanisms. Increasing temperatures are expected to make wet regions wetter and dry regions drier (thermodynamic changes); and changes in atmospheric circulation patterns will push storm tracks and subtropical dry zones toward the poles.

"Both these changes are occurring simultaneously in global precipitation and this behavior cannot be explained by natural variability alone," said LLNL's lead author Kate Marvel. "External influences such as the increase in greenhouse gases are responsible for the changes."

The team compared climate model predications with the Global Precipitation Climatology Project's global observations, which span from 1979-2012, and found that natural variability (such as El Niños and La Niñas) does not account for the changes in global precipitation patterns. While natural fluctuations in climate can lead to either intensification or poleward shifts in precipitation, it is very rare for the two effects to occur together naturally.

"In combination, manmade increases in greenhouse gases and stratospheric ozone depletion are expected to lead to both an intensification and redistribution of global precipitation," said Céline Bonfils, the other LLNL author. "The fact that we see both of these effects simultaneously in the observations is strong evidence that humans are affecting global precipitation."

Marvel and Bonfils identified a fingerprint pattern that characterizes the simultaneous response of precipitation location and intensity to external forcing.

"Most previous work has focused on either thermodynamic or dynamic changes in isolation. By looking at both, we were able to identify a pattern of precipitation change that fits with what is expected from human-caused climate change," Marvel said.

By focusing on the underlying mechanisms that drive changes in global precipitation and by restricting the analysis to the large scales where there is confidence in the models' ability to reproduce the current climate, "we have shown that the changes observed in the satellite era are externally forced and likely to be from man," Bonfils said

N.H.Khider

Source : Science daily

World Ocean Systems Undermined by Climate Change by 2100

An ambitious new study describes the full chain of events by which ocean biogeochemical changes triggered by humanmade greenhouse gas emissions may cascade through marine habitats and organisms, penetrating to the deep ocean and eventually influencing humans.

Previous analyses have focused mainly on ocean warming and acidification, considerably underestimating the biological and social consequences of climate change. Factoring in predictable synergistic changes such as the depletion of dissolved oxygen in seawater and a decline in productivity of ocean ecosystems, the new study shows that no corner of the world ocean will be untouched by climate change by 2100.

"When you look at the world ocean, there are few places that will be free of changes; most will suffer the simultaneous effects of warming, acidification, and reductions in oxygen and productivity," said lead author Camilo Mora, assistant professor at the Department of Geography in the College of Social Sciences at the University of Hawai'i at Mānoa (UH Mānoa). "The consequences of these co-occurring changes are massive -- everything from species survival, to abundance, to range size, to body size, to species richness, to ecosystem functioning are affected by changes in ocean biogeochemistry."

The human ramifications of these changes are likely to be massive and disruptive. Food chains, fishing, and tourism could all be impacted. The study shows that some 470 to 870 million of the world's poorest people rely on the ocean for food, jobs, and revenues, and live in countries where ocean goods and services could be compromised by multiple ocean biogeochemical changes.

Mora and Craig Smith with UH Mānoa's School of Ocean and Earth Science and Technology (SOEST) worked with a 28-person international collaboration of climate modelers, biogeochemists, oceanographers, and social scientists to develop the study, which is due for publication October 15 in the scientific journal PLOS Biology.

The researchers used the most recent and robust models of projected climate change developed for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) to inform their analysis. They quantified the extent of co-occurrence of changes in temperature, pH, oxygen, and primary productivity based on two scenarios: a business-as-usual scenario wherein atmospheric CO2 concentrations could reach 900 ppm by 2100, and an alternative scenario under which concentrations only reach 550 ppm by 2100 (representing a concerted, rapid CO2 mitigation effort, beginning today).

They discovered that most of the world's ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. Only a very small fraction of the oceans, mostly in polar regions, will face the opposing effects of increases in oxygen or productivity, and nowhere will there be cooling or pH increase.

"Even the seemingly positive changes at high latitudes are not necessary beneficial. Invasive species have been immigrating to these areas due to changing ocean conditions and will threaten the local species and the humans who depend on them," said co-author Chih-Lin Wei, a postdoctoral fellow at Ocean Science Centre, Memorial University of Newfoundland, Canada.

The researchers assembled global distribution maps of 32 marine habitats and biodiversity hotspots to assess their potential vulnerability to the changes. As a final step, they used available data on human dependency on ocean goods and services and social adaptability to estimate the vulnerability of coastal populations to the projected ocean biogeochemical changes.

"Other studies have looked at small-scale impacts, but this is the first time that we've been able to look the entire world ocean and how co-occurring stressors will differentially impact the earth's diverse habitats and people," said co-author Andrew Thurber, a postdoctoral fellow at Oregon State University. "The real power is in the quantitative, predictive approach using IPCC climate models that allow us to see how much it will all change, and also how confident we can be in our estimates."

By 2100, global averages for the upper layer of the ocean could experience a temperature increase of 1.2 to 2.6° C, a dissolved oxygen concentration reduction of ~2% to 4% of current values, a pH decline of 0.15 to 0.31, and diminished phytoplankton production by ~4% to 10% from current values. The seafloor was projected to experience smaller changes in temperature and pH, and similar reductions in dissolved oxygen.

Of the many marine habitats analyzed in the study, researchers found that coral reefs, seagrass beds, and shallow soft-bottom benthic habitats would experience the largest absolute changes in ocean biogeochemistry, while deep-sea habitats would experience the smallest changes.

Co-author Lisa Levin, a professor at Scripps Institution of Oceanography at the University of California, San Diego, notes: "Because many deep-sea ecosystems are so stable, even small changes in temperature, oxygen, and pH may lower the resilience of deep-sea communities. This is a growing concern as humans extract more resources and create more disturbances in the deep ocean."

"The deep-sea floor covers most of the Earth's surface and provides a whole host of important ecosystem services including carbon sequestration in seafloor sediments, buffering of ocean acidity, and providing an enormous reservoir of biodiversity," said Smith. "Nonetheless, very little attention has been paid to modeling the effects of climate change on these truly vast ecosystems. Perhaps not surprisingly, many deep seafloor ecosystems appear susceptible to the effects of climate warming over the next century."

"The impacts of climate change will be felt from the ocean surface to the seafloor. It is truly scary to consider how vast these impacts will be," said co-author Andrew K. Sweetman, who helped to convene the original team of investigators and now leads the deep-sea ecosystem research group at the International Research Institute of Stavanger, Norway. "This is one legacy that we as humans should not be allowed to ignore."

Source:Science Daily

R.S

Awareness, Information Strategy Approved

DAMASCUS, (ST) - The Ministry of State for Environmental Affairs recently approved the national strategy to raise awareness and the environmental media in Syria in order to develop the knowledge and skills of the segments of the society to preserve the environment , protect and develop the skills of the cadres of the working bodies in the field of media and environmental awareness to preserve the components of the environment and promotion of community participation in environmental management.

During the meeting of the National Committee to raise awareness and environmental  media, the Minister of State for Environmental Affairs, Dr. Naira Sarkis, pointed out that the ministry adopted the strategy after it had been presented to the parties participating in the membership of the National Committee to raise awareness and the environment media and discussing the observations and amendments to the proposed strategy set by the ministry.

The Minister of State for Environmental Affairs stressed on the need to accelerate the application of the terms of the strategy on the ground and carry out field activities that focus on raising awareness about environmental issues and problems faced by Syria and the definition of the negative consequences that these problems leave in the future on humans and the environment.

Dr. Sarkis stressed that the ministry is coordinating with all government and private bodies and civil society in order to promote environmental awareness among different segments of society as well as to carry out projects and campaigns to raise awareness with these bodies , noting the importance of educating citizens, especially in the current stage which requires the awareness of citizens and directing them to preserve natural resources and the environment.

Director of Awareness and Environmental Information at the Ministry of Environment, Dr. Nader Ghazi, reviewed the proposals, ideas and amendments made by the bodies involved regarding the strategy its objectives, justifications and characteristics , as well as the role required of each party to do in promoting environmental awareness.

It is worth mentioning, that the Ministry of State for Environmental Affairs reshaped the National Committee to raise awareness and environmental  media in order to promote environmental awareness and ensure the sustainability of natural resources, chaired by the Ministry of Environment and with the participation of representatives of all bodies concerned at the level of state and private sector.

Sh. Kh.

Climate Puzzle Over Origins of Life On Earth

The mystery of why life on Earth evolved when it did has deepened with the publication of a new study in the latest edition of the journal Science.

Scientists at the CRPG-CNRS University of Lorraine, The University of Manchester and the Institut de Physique du Globe de Paris have ruled out a theory as to why the planet was warm enough to sustain the planet's earliest life forms when the Sun's energy was roughly three-quarters the strength it is today.

Life evolved on Earth during the Archean, between 3.8 and 2.4 billion years ago, but the weak Sun should have meant the planet was too cold for life to take hold at this time; scientists have therefore been trying to find an explanation for this conundrum, what is dubbed the 'faint, young Sun paradox'.

"During the Archean the solar energy received at the surface of the Earth was about 20 to 25 % lower than present," said study author, Dr Ray Burgess, from Manchester's School of Earth, Atmospheric and Environmental Sciences. "If the greenhouse gas composition of the atmosphere was comparable to current levels then the Earth should have been permanently glaciated but geological evidence suggests there were no global glaciations before the end of the Archean and that liquid water was widespread."

One explanation for the puzzle was that greenhouse gas levels -- one of the regulators of Earth's climate -- were significantly higher during the Archean than they are today.

"To counter the effect of the weaker Sun, carbon dioxide concentrations in the Earth's atmosphere would need to have been 1,000 times higher than present," said lead author Professor Bernard Marty, from the CRPG-CNRS University of Lorraine. "However, ancient fossil soils -- the best indicators of ancient carbon dioxide levels in the atmosphere -- suggest only modest levels during the Archean. Other atmospheric greenhouse gases were also present, in particular ammonia and methane, but these gases are fragile and easily destroyed by ultraviolet solar radiation, so are unlikely to have had any effect."

But another climate-warming theory -- one the team wanted to test -- is that the amount of nitrogen could have been higher in the ancient atmosphere, which would amplify the greenhouse effect of carbon dioxide and allow Earth to remain ice-free.

The team analysed tiny samples of air trapped in water bubbles in quartz from a region of northern Australia that has extremely old and exceptionally well-preserved rocks.

"We measured the amount and isotopic abundances of nitrogen and argon in the ancient air," said Professor Marty. "Argon is a noble gas which, being chemically inert, is an ideal element to monitor atmospheric change. Using the nitrogen and argon measurements we were able to reconstruct the amount and isotope composition of the nitrogen dissolved in the water and, from that, the atmosphere that was once in equilibrium with the water."

 

The researchers found that the partial pressure of nitrogen in the Archean atmosphere was similar, possibly even slightly lower, than it is at present, ruling out nitrogen as one of the main contenders for solving the early climate puzzle.

Dr Burgess added: "The amount of nitrogen in the atmosphere was too low to enhance the greenhouse effect of carbon dioxide sufficiently to warm the planet. However, our results did give a higher than expected pressure reading for carbon dioxide -- at odds with the estimates based on fossil soils -- which could be high enough to counteract the effects of the faint young Sun and will require further investigation."

Source:Science Daily

R.S

Study Could Help Improve Nuclear Waste Repositories

Here’s the question faced by a team of Sandia National Laboratories researchers: How fast will iodine-129 released from spent nuclear fuel move through a deep, clay-based geological repository?

Understanding that process is crucial as countries worldwide consider underground clay formations for nuclear waste disposal, because clay offers low permeability and high radionuclide retention. Even when a repository isn’t sited in clay, engineered barriers often include a compacted buffer of bentonite, a common type of clay, to improve waste isolation.

Iodine-129, a radioactive isotope with a half-life of 15.7 million years, is an important fission product in spent nuclear fuel and a major contributor to the predicted total radiation dose from a deep geological repository. So even a small improvement in the ability of clay to retain iodine-129 can make a difference in total dose predictions.

Some evidence indicates weak interaction between clay and iodide — a negatively charged predominant chemical species of iodine in geologic repositories, said researcher Yifeng Wang, who leads the study. Computer models haven’t been able to adequately explain clay’s chemical behavior with iodide, and the mechanism is difficult to study because the faint interaction is easily masked by measurement uncertainties.

 “It seems there’s some kind of previously unrecognized mechanism that accounts for that kind of interaction,” said Wang, co-principal investigator for the Laboratory Directed Research and Development project to study radionuclide-clay interaction, now in its third and final year.

His team concluded the interaction, often disregarded as experimental noise, is real and that there might be engineering ways to improve clay’s ability to retain iodide.

The team — Wang and former co-principal investigator Andy Miller, who recently left Sandia; technician Hernesto Tellez; and year-round interns Jessica Kruichak and Melissa Mills — developed experiments with different clays, focusing on their structural characteristics. Past studies of iodide retention in clay concentrated on bentonite. Wang’s team instead studied several different clays, five with the same type of layered structure as bentonite.

Although industries are accustomed to using the plentiful and oft-studied bentonite, the team’s experiments show other clays have higher radionuclide retention capability and might isolate spent fuel waste better. Kaolinite had the best iodide retention of the five clays with layering properties. Wang said the team believes its work “can help us select a better clay material or combination of clay materials.”

Team members believe they discovered a mechanism for iodide-clay interactions that allows more accurate prediction of iodine-129 movement in a geologic repository. The finding was presented in May to the International High Level Radioactive Waste Management Conference in Albuquerque and was published in the conference proceeding.

 

The experimental data indicate iodide directly interacts with the tiny spaces between the layers of clay, called clay interlayer sites. That raises the question of how negatively charged iodide gets into those negatively charged interlayer sites, since like charges repel each other, similar to magnets of the same polarity. “So that contradicts the conventional concept,” Wang said.

The team got clues about what was going on by studying the problem at the nanoscale, 100,000 times smaller than the diameter of a human hair. At that scale, Wang said, the property of water changes in a way that enhances the pairing of ions.

Source:Science Daily

Sh/Kh