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G24 INSTA NWT_Earth NWT_Environment SCI

Blocking sunlight to cool Earth decrease global warming crop damage

An new study suggests that blocking sunlight by injecting particles into the atmosphere will not offset the crop damage caused by global warming. The team behind the study analyzed past effects of Earth-cooling volcanic eruptions and how crops respond to changes in sunlight to come to their conclusion.

“Shading the planet keeps things cooler, which helps crops grow better. But plants also need sunlight to grow, so blocking sunlight can affect growth. For agriculture, the unintended impacts of solar geoengineering are equal in magnitude to the benefits,” said lead author Jonathan Proctor of the University of California, Berkeley. “It’s a bit like performing an experimental surgery; the side-effects of treatment appear to be as bad as the illness.”

“Unknown unknowns make everybody nervous when it comes to global policies, as they should,” said Solomon Hsiang, co-lead author of the study and also from UC Berkeley. “The problem in figuring out the consequences of solar geoengineering is that we can’t do a planetary-scale experiment without actually deploying the technology. The breakthrough here was realizing that we could learn something by studying the effects of giant volcanic eruptions that geoengineering tries to copy.”

The team stresses the more research is needed into the ecological and human consequences of geoengineering.

“The most certain way to reduce damages to crops and, in turn, people’s livelihood and well-being, is reducing carbon emissions,” Proctor said.

“Perhaps what is most important is that we have respect for the potential scale, power and risks of geoengineering technologies,” Hsiang added. “Sunlight powers everything on the planet, so we must understand the possible outcomes if we are going to try to manage it.”

The findings were published in Nature.

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Geology NWT_Earth SCI

Scientists believe diamonds are under Earth’s surface

According to an international team of scientists, there may be quadrillion tons of diamonds under the surface of the Earth. The deposits are in cratonic roots between 90 and 150 miles below the surface.

“This shows that diamond is not perhaps this exotic mineral, but on the (geological) scale of things it’s relatively common,” said Ulrich Faul, co-author of the study and a research scientist at MIT. They discovered there is much more diamond than they ever thought there could be.

MIT News describes cratons as the oldest and most immovable sections of rock. They are stable chunks of the Earth’s crust and are in the shape of inverted mountains.

The deepest parts are the roots that can reach all the way to the Earth’s mantle. The authors of the study believe the diamonds are in the mantle.

They used seismic data – or recorded sound waves from seismic activity to locate the diamonds. This data helped them measure what the Earth is made of.

Then, the team used 3D modeling to create virtual rocks in a quest to figure out what substances could compose the roots of cratons. Diamonds seemed to foot the bill.

The diamonds matched the velocity of the sound traveling through the roots. They estimated that the roots must be made of 1 to 2 percent diamond.

Using this estimate, and the number of known craton roots, the scientists arrived at their quadrillion-ton estimate. It is 1,000 times more than they first thought.

 

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NWT_Earth NWT_Environment SCI

Antarctic snowfall increased over the last two centuries

Antarctica has experienced a 10 percent increase in snowfall over the last 200 years, according to recent research set to be presented at the European Geosciences Union in Vienna, Austria

This new discovery comes from a group of scientists with the British Antarctic Survey, who analyzed Antarctic ice cores and found that the continent accumulated nearly 272 gigatons of water over the last two centuries. Almost all of that extra water came from increased snowfall.

Such information is important because, not only does it alter the current perception of Antarctica’s climate, but it could change current sea level rise models as well.

“There is an urgent need to understand the contribution of Antarctic ice to sea-level rise and we use a number of techniques to determine the balance between snowfall and ice loss,” lead author Elizabeth Thomas, a researcher with the British Antarctic Survey, said in a statement. “When ice loss is not replenished by snowfall then sea level rises.”

Satellite pictures — which often help researchers understand shifting climates — typically only give information going back 20 years or so. As a result, ice core analysis, which are able to track snowfall for several hundred years, are more effective. In this case, they revealed that Antarctica’s surface mass balance drastically shifted from snowfall throughout the twentieth century.

Though the snowfall is everywhere, it mainly concentrated on the Antarctic Peninsula. There, the annual average is 10 percent higher than it was 200 years ago.

This discovery could alter current perceptions of climate change, but the team states the findings do not override any observations of melting or glacial retreat. Even so, they will allow scientists make more accurate sea level rise predictions as time goes on.

“We know that the two major influencers affecting change — the mass gain from snowfall and the mass loss from melting — are acting differently from one another,” added Thomas, according to UPI. “Our new findings take us a step towards improving our knowledge and understanding.”

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NWT_Earth Research SCI

Life on Earth evolved earlier than previously thought, study says

Researchers from the University of Bristol have created a new timescale of life on Earth, which suggests that it evolved earlier than we previously thought. The new study combined fossil and genomic data to come to its surprising conclusion.

The fossil record on Earth is very fragmented, with a significant deterioration observed back in time towards the Archaen period that took place over 2.5 billion years ago. During this time, the Earth’s crust cooled enough to pave the way for the formation of continents and microbe lifeforms.

“There are few fossils from the Archaean and they generally cannot be unambiguously assigned to the lineages we are familiar with, like the blue-green algae or the salt-loving archaebacteria that colours salt-marshes pink all around the world,” said Holly Betts, lead author of the study.

“The problem with the early fossil record of life is that it is so limited and difficult to interpret—careful reanalysis of the some of the very oldest fossils has shown them to be crystals, not fossils at all,” she continued.

By combining genomic and fossil information, the team found that the Last Universal Common Ancestor (LUCA) of all cellular life forms existed nearly 4.5 billion years ago, which is earlier than the oldest known fossil evidence suggests.

“Our results indicate that two ‘primary’ lineages of life emerged from LUCA (the Eubacteria and the Archaebacteria), approximately one Billion years after LUCA,” said co-author and professor Davide Pisani.

“This result is testament to the power of genomic information, as it is impossible, based on the available fossil information, to discriminate between the oldest eubacterial and archaebacterial fossil remains,” he added.

The findings were published in Nature Ecology & Evolution.

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NWT_Climate NWT_Earth Research SCI

Earth at risk of heading toward ‘hothouse’ conditions

A new study suggests that even if we meet the carbon emission reductions outlined in the Paris Agreement, the Earth is still at risk of entering “hothouse” conditions. Given the findings, the authors believe that it is critical that we quickly move toward an emission-free world economy.

“Human emissions of greenhouse gas are not the sole determinant of temperature on Earth,” said lead author Will Steffen from the Australian National University and Stockholm Resilience Centre. “Our study suggests that human-induced global warming of 2 degrees C may trigger other Earth system processes, often called feedbacks, that can drive further warming—even if we stop emitting greenhouse gases. Avoiding this scenario requires a redirection of human actions from exploitation to stewardship of the Earth system.”

As of now, global average temperatures are sitting just over 1 degrees Celsius past pre-industrial and increasing at 0.17 degrees Celsius each decade.

In order to avoid a “Hothouse Earth,” we must reduce carbon dioxide and greenhouse gas emissions and enhance biological carbon stores through methods such as improved forest management and biodiversity conservation.

“Climate and other global changes show us that we humans are impacting the Earth system at the global level,” said study co-author Katherine Richardson from the University of Copenhagen. “This means that we as a global community can also manage our relationship with the system to influence future planetary conditions. This study identifies some of the levers that can be used to do so,”

The findings were published in the Proceedings of the National Academy of Sciences.

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NWT_Climate NWT_Earth NWT_Environment SCI

Ocean acidification is majorly impacting marine life, study says

A new study continues to shed light on the effects of industrial development on our seas by revealing that carbon dioxide emissions are destroying kelp forests and corals reefs. The damages are reportedly from the ocean acidification and heat waves created by climate change.

“These CO2 seeps provide a vital window into the future,” said lead author Sylvain Agostini, Associate Professor at the University of Tsukuba Shimoda Marine Research Centre. “There was mass mortality of corals in the south of Japan last year, but many people cling to the hope that corals will be able to spread north.”

“Therefore it is extremely worrying to find that tropical corals are so vulnerable to ocean acidification, as this will stop them from being able to spread further north and escape the damage caused by water that is too hot for them,” he continued.

“Our research site is like a time machine,” said Jason Hall-Spencer, Professor of Marine Biology at the University of Plymouth. “In areas with pre-Industrial levels of CO2 the coast has an impressive amount of calcified organisms such as corals and oysters. But in areas with present-day average levels of surface seawater CO2 we found far fewer corals and other calcified life, and so there was less biodiversity.”

The new data shows the large amount of damage stemming from human-created carbon dioxide emissions over the last 300 years.

“Unless we can get a grip on reducing CO2 emissions we will undoubtedly see major degradation of coastal systems worldwide,” Hall-Spencer said.

The findings were published in Scientific Reports.

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NWT_Earth TECH

‘Slow earthquakes’ on San Andreas Fault raise risks of massive quakes

New interpretations by two Arizona State University geophysicists reveal that the earth movements along a central section have not been smooth and steady, as previously estimated.

The activity has been a sequence of small stick-and-slip movements referred to as “slow earthquakes” which release energy over a period of months.

Researchers say they can trigger large destructive quakes in their surroundings. One such quake was the magnitude 6 event that shook Parkfield in 2004.

Mostafa Khoshmanesh, a graduate research assistant in ASU’s School of Earth and Space Exploration (SESE), states, “What looked like steady, continuous creep was actually made of episodes of acceleration and deceleration along the fault.”

“We found that movement on the fault began every one to two years and lasted for several months before stopping,” said Manoochehr Shirzaei, assistant professor in SESE and co-author of the paper.

Episodic slow earthquakes result in prolonged stress on the locked segments of the fault to the north and south of the central section.

Shirzaei notes that these flanking sections experienced two magnitudes 7.9 earthquakes, in 1857 (Fort Tejon) and 1906 (San Francisco).

The scientists also suggest a mechanism that might cause the stop-and-go movements.

“Fault rocks contain a fluid phase that’s trapped in gaps between particles, called pore spaces,” Khoshmanesh said. “Periodic compacting of fault materials causes a brief rise in fluid pressure, which unclamps the fault and eases the movement.”

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NWT_Earth TECH

Earth’s rivers cover 44 percent more land than recognized

A new global map of rivers and streams created using satellite data suggests that the global surface area of these bodies of water is about 44% higher than previously thought, according to the American Association for the Advancement of Science.

Particularly two studies to date have attempted to quantify the global surface area of rivers, noting that these were based on limited data.

Important and complex chemical exchanges with the atmosphere and biosphere happen at the water-atmosphere interface of rivers. The study provides examples, such as rivers releasing roughly one-fifth of the carbon dioxide levels emitted by fossil fuel combustion and cement production.

Using satellite data, George Allen and Tamlin Pavelsky created one of the most detailed databases of rivers and streams to date, called the Global River Widths from Landsat (GRWL) Database. It quantifies the surface area of rivers greater than 90 kilometers (km) in width.

The authors performed a series of calculations to account for smaller rivers, for which less data is available. Collectively, global rivers and streams were estimated to cover roughly 773,000 km2 of Earth’s global non-glaciated land surface – tens of thousands of kilometers squared higher than previous estimates.

Regionally, authors Allen and Pavelsky report more river surface area coverage in the Arctic, distinctly where the impacts of climate change on carbon fluxes are of a major concern than previous estimates have ballparked. Remarkably, the report displays less in Europe, the U.S., and other economically developed regions.

Allen and Pavelsky note that the “lower-than-previous estimate of river surface area” in many developed areas may suggest large-scale impacts of human modification on river networks, emphasizing the hypothesis necessitates additional examination.

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NWT_Earth NWT_Environment

Global warming signs are everywhere

While it is easy to assume that climate change only comes in the form of rising oceans or extreme weather events, signs of global warming are all around us every single day.

An example of this comes from David Inouye, a researcher from the University of Maryland who studied when wildflowers and their pollinators began appearing around the Rocky Mountain Biological Lab. Diligent research over numerous decades revealed the species show up roughly two to three weeks earlier — mid-March as opposed to early April — than they did 30 years ago. In addition, birds also show up earlier and marmots end their winter slumber before they used to.

‘‘If the climate weren’t changing, we wouldn’t see these kind of changes happen,’’ explained Inouye, according to The Boston Globe.

It has been almost 30 years since scientists began analyzing global warming. Though the climate is the main focus, new studies show that all of nature has gone through shifts.

In fact, interviews with more than 50 scientists combined with an Associated Press analysis of data on plants, animals, pollen, ice, and sea levels show just how impactful the process is.

That research showed that there are 28,800 cases of plants and animals ‘‘responding consistently to temperature changes.’’ Blueberry patches at Walden Pond now bloom earlier as a result of warmer temperatures while many species come out of hibernation at different times.

Spring now occurs earlier than it used to, and fall starts much later on. All of those shifts have massive impacts on different ecosystems and radically change both animal and plant behavior.

It can affect humans as well. For instance, studies on ragweed growth shows that warmer springs lead to an increased number of high pollen days. Allergies and asthma are also both on the rise.

While climate change is not the only reason for these shifts, it is a primary factor and something scientists hope officials keep in mind moving forward.

‘‘If you don’t trust the thermometers, throw them out,’’ said Katharine Hayhoe, a climate scientist at Texas Tech, according to The Washington Post. ‘‘All we have to do is look at what’s happening in nature.’’

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NWT_Earth NWT_Environment

Antarctica steadily rising over time, study reports

Thinning ice has caused bedrock deposits underneath Antarctica to rise higher than ever before, a new study published in the journal Science reports.

As ice melts, it takes weight off the bedrock below. Though that process does not happen right away, large amounts of ice have melted across Antarctica through the years. That in turn caused the bedrock to rise up in response.

This new finding — which comes from researchers at the Technical University of Denmark — is both good and bad news.

It is good news because the uplift of supporting bedrock may help anchor other ice sheets and make them more stable. However, the rising rock has likely skewed past satellite measurements on ice loss and those predictions may be underestimated by as much as 10 percent.

Though computer models help scientists understand how the Earth’s mantle behaves, they do not have a full idea of the different reactions that drive its mechanisms. These findings are a good example of such processes, and they could shed more light on the geological movements of our planet.

“The study of this — the distribution of viscosity in the mantle — is still in its infancy,” said lead study author Valentina Barletta, a postdoctoral researcher at DTU Space, the National Space Institute at the Technical University of Denmark, according to Live Science. “We know where the Earth is hotter and cooler — more or less. However, the viscosity of the mantle depends not just on temperature, but also on water content.”

While scientists previously believed changes like the ones in the recent study took tens of thousands of years, the newly documented process occurred over decades. That suggests the mantle under Antarctica may flow more quickly than previously suspected.

To measure those changes, the team installed six GPS stations at locations around a region of the ice sheet known as the Amundsen Sea Embayment (ASE). They placed the monitors at exposed bedrock and gathered data at a spatial resolution of 0.6 miles.

That revealed the rising bedrock.

The team hopes this new information will be incorporated into models and help inform future decisions. 

“These data will be of great value to the modeling community who examine the complex relationships between GIA, sub-ice shelf ocean circulation, and ultimately, ice sheet stability,” said Doug Kowalewski, the Antarctic Earth Sciences program director in the National Science Foundation’s Office of Polar Programs (OPP) who was not involved in the research, according to Phys.org.