Global Warming Responsible for 70 Percent of Recent Glacier Loss, Study Finds

August 15, 2014 by admin  
Filed under Global Warming

From Alaska to the Andes, glaciers all over the world have been retreating for decades, as average global surface temperatures have increased. This loss of these glaciers is one of the most iconic manifestations of manmade global warming, but until now, no one had studied the obvious question: Just how much global glacier melt (referred to technically as “glacier mass loss”) is global warming responsible for, and how much is from natural climate variability?

A new study, published Thursday in the journal Science Express, tackles that question, and comes to a profound — if not surprising— conclusion. The study found that manmade global warming, which is largely due to the burning of fossil fuels such as oil and coal for energy, is responsible for nearly 70% of global glacier mass loss between 1991 to 2010.

See also: Sea Level Rise Visualization Shows Your Home — Underwater

Glaciers are melting because of human actions, which implies that also related impacts, such as changed water availability and hazards from glacial lakes can be considered man-made,” lead author Ben Marzeion, with the University of Innsbruck, told Mashable.

The study, by researchers at the University of Innsbruck and Trent University, found that over a longer time period, from 1851-2010, the manmade signal is smaller, accounting for about 25% of glacier melt. Part of the reason for this is that during the early decades within that time, period glaciers were still responding to natural climate variability, including the end of the so-called “Little Ice Age” when temperatures were considerably cooler than they are now.

Greenland Glacier

Meltwater channels from the previous summer and terminus of the Violin Glacier in East Greenland, seen during an Operation IceBridge survey flight on April 5, 2014. Image: NASA IceBridge

The study showed that glaciers are still responding to climate change that occurred years ago because they have a delayed response to warming. This means that the accelerated warming seen since the 1970s is likely to cause even more melting in the coming years, even though temperatures rose much more slowly during the past decade.

Melting glaciers are a hazard because they contribute to rising sea levels, which are already causing coastal storms to be more destructive, and also altering water resources; this leads to flooding hazards in many areas, such as the Himalayas. Without manmade global warming, glaciers would have contributed about 3.9 inches to global sea level rise during the 1851 to 2010 period, the study found; but with it, they contributed 5.2 inches.

This may sound like a small number, but every fraction of an inch can make a huge difference when it comes to storm surge in highly populated coastal cities. For example, the foot of sea level rise during the past century in New York City was enough for Hurricane Sandy’s storm surge to flood thousands of additional homes and businesses than the storm would have without that extra water.

Anderson-Glacier-1936-2004-pair_1

The Anderson Glacier in Olympic National Park in 1936, and again in 2004. Credit: National Park Service. Image: National Park Service

The study said that in some areas, it is quite clear that manmade global warming is driving glaciers to shrink, including Alaska, western Canada, Arctic Canada, Greenland and north Asia, among others. But in some spots, such as the southern Andes and Caucasus region, the study’s methods did not detect a manmade warming signal with high confidence.

To arrive at their conclusions, the researchers used a model of global glacier evolution based in part on the Randolph Glacier Inventory, which contains information for individual glaciers, as well as the latest global climate models to simulate the contribution of natural and manmade climate change. They found that the computer model simulations could not match the observed record without including manmade global warming. The study includes all of the world’s glaciers outside of Antarctica.

Richard B. Alley, a geosciences professor at Pennsylvania State University who was not involved in the new study, described glaciers as “slow thermometers.” In an email to Mashable, he said:

Stick a fever thermometer in your mouth, and it takes a little while to adjust to the new environment and give the accurate temperature. In the same way, if there were a temperature change in a single step, with the temperature then held constant at that new level, a glacier will take a while to come into balance with the new temperature…

High scientific confidence that the human-dominated part of the warming is primarily responsible for glacier retreat thus doesn’t emerge until late in the 20th century, even though the “most likely” answer is that humans have been contributing at least a little for over a century, with a growing influence more recently.

Alley added that the study’s results “make perfect sense.”

“Warming melts glaciers, whether the warming is caused by natural or human causes. And because glaciers are slow thermometers, even if humans were to quit warming the climate, the glaciers will lose more mass in the future as they “catch up” with the warming that has already occurred,” he said.

Eric Steig, a University of Washington professor who was not involved in the new study, said it is “convincing, but not at all surprising.” He added that the lagged response of glaciers doesn’t go back more than a few decades for most small glaciers, and about a century for larger ones.

Marzeion, the study’s lead author, cautioned that there are still uncertainties about how some glaciers are responding to climate change, and improvements also need to be made to computer models of the climate. Those caveats, however, do not detract much from the bottom-line message that manmade global warming is now the primary reason why glaciers are melting.

Article source: http://mashable.com/2014/08/15/global-warming-glacier-loss/

Ants May Boost CO2 Absorption Enough to Slow Global Warming

August 12, 2014 by admin  
Filed under Global Warming

What if you could build a brick fence in your backyard that would offset a portion of your daily carbon dioxide emissions, such as those produced on your drive home from work? Would you do it?

Ronald Dorn, professor of geography at Arizona State University in Tempe, would. Except the fence he has in mind wouldn’t be just constructed from any old brick. It would be coated with calcium or magnesium and inhabited by a colony of ants.

If this idea sounds bizarre to you, that’s probably because—as Dorn himself would admit—it is. Yet, he says, it is conceivable that people all over the world could one day use their own version of this mineral/ant–based method of CO2 capture to limit the gas in the atmosphere and thereby help control its global heating effects.

CO2 is currently the primary greenhouse gas emitted via human activities, according to the U.S. Environmental Protection Agency’s Overview of Green House Gases. And the volume released has only increased since the industrial revolution, contributing to global warming.

Using ants to help capture CO2 and help fight global warming stems from a study Dorn published recently in Geology linking ants to the acceleration of natural carbon dioxide absorption in rock by up to 335 times, compared with absorption in ant-free areas.

Responding to the study, David Schwartzman, emeritus professor of biogeochemistry at Howard University who reviewed but was not a part of the research, said that encouraging ant colonization “will be important in carbon sequestration” from the atmosphere.

Of course, both he and Dorn note, the ants themselves may not always be necessary once researchers learn more about how the insects promote carbon sequestration. “I don’t know if you can just have massive ant colonies hanging around a power plant. But if we know what particular secretion of an ant gland is doing this trick, or combinations of secretions,” Dorn says, then those substances could potentially be produced in quantity.

How rock captures carbon
Dorn himself is not sure how ants perform their “magic,” but he does have a good handle on how certain rocks absorb carbon on their own.

He says that rock containing calcium and magnesium naturally absorbs carbon dioxide, which in turn transforms it into carbon-rich limestone, or dolomite. This carbon capture by rock has been happening for a very long time. In fact, over geologic time it probably helped to keep the planet’s atmospheric CO2 levels and its temperature from rising too high for life to survive. Dorn’s new research suggests ants could have been responsible for helping accelerate this process.

Overall Dorn says this chemical activity really is essential to making Earth habitable. It is so important that he has his students do a rather unusual ceremony when working out in the field for research projects. “When I take students on field trips, I make them kiss the limestone, because that limestone is just CO2 that’s just locked up in rocks and how Earth has remained habitable.”

From annoyance to anomaly
Dorn discovered the contribution ants can make almost by accident. In the 1990s, as part of studying the weathering of minerals, he stuck minerals in all sorts of different areas—in soil, in bare ground, in crusts ripe with microorganisms, in ground next to roots and in a plastic tube used as a control. You name it, he did it—he wanted a baseline from which to track changes over time, he says.

At first, the ants were mainly an annoyance. “I’d drill holes and they’d bite you,” he says. It wasn’t until after putting up with them for 25 years while taking measurements of the minerals’ weathering over time that he got his first inkling of their carbon-sequestering prowess. “It was pretty clear when I started processing samples of the minerals from the different areas that the ants were incredibly anomalous,” he says, referring to just how much the ants sped up the carbon-capture process. Follow-up work then quantified the amount of carbon stored in rocks visited by ants.

And although he still isn’t sure whether it’s the ants licking the rock, their microbes, their gland secretions or something else that accounts for the carbon enhancement in rocks, he does understand further insight into the process could potentially help people do a better job of capturing carbon from the atmosphere. “I don’t understand how the ants are doing the processes,” he says. “I would love to get funding to figure this out…. Then we could move forward to work with the chemical engineers or somebody to figure out if this magic trick can be efficiently and economically used. That would be a dream.”

Schwartzman agrees and says that such carbon sequestration will be imperative in bringing down the atmospheric level of CO2 to below 350 parts per million (it is now 400 ppm) “to avoid the worst consequences of ongoing climate change induced by anthropogenic releases of CO2 to the atmosphere.” Although he added that this carbon release must also be radically and rapidly curbed as well.

Regardless, there are over 10 trillion ants on Earth, according to some estimates. So, “clearly, more studies on the role of ants and other animals populating soils are needed to broaden our understanding of their significance,” Schwartzman says.

Article source: http://www.scientificamerican.com/article/ants-may-boost-co2-absorption-enough-to-slow-global-warming/

10883 out of 10885 scientific articles agree: Global warming is happening…

March 25, 2014 by admin  
Filed under Featured, Global Warming

As geochemist James Lawrence Powell continues to prove, the only people still debating whether or not climate change is “real,” and caused by human activity, are the ones who aren’t doing the actual research. In an update to his ongoing project of reviewing the literature on global warming, Powell went through every scientific study published in a peer-review journal during the calendar year 2013, finding 10,885 in total (more on his methodology here). Of those, a mere two rejected anthropogenic global warming. The consensus, as he defines it, looks like this:

Powell even had to expand that itty bitty slice of the consensus pie five times for us to make it out  – the actual doubt about climate change within the scientific community is even tinier.

Adding this new data to his previous findings, Powell estimates that the going rate for climate denial in scientific research is about 1 in 1,000. The outliers, he adds, “have had no discernible influence on science.” From this, he comes up with a theory of his own:

Very few of the most vocal global warming deniers, those who write op-eds and blogs and testify to congressional committees, have ever written a peer-reviewed article in which they say explicitly that anthropogenic global warming is false. Why? Because then they would have to provide the evidence and, evidently, they don’t have it.

What can we conclude?

1. There a mountain of scientific evidence in favor of anthropogenic global warming and no convincing evidence against it.

2. Those who deny anthropogenic global warming have no alternative theory to explain the observed rise in atmospheric CO2 and global temperature.

These two facts together mean that the so-called debate over global warming is an illusion, a hoax conjured up by a handful of apostate scientists and a misguided and sometimes colluding media, aided and abetted by funding from fossil fuel companies and right wing foundations.



UPDATE 3/26/2014 9:27 PM: The headline of this post has been corrected to reflect the correct number of articles referenced by Dr. Powell’s research. Powell also clarifies that many of those studies were authored by multiple scientists, so the complete number is actually higher. The headlines has been updated to reflect this as well.

On his methodology, Powell notes, he only verified that two out of the 10,885 articles he found concluded that anthropogenic global warming (AGW) is wrong: “It is a safe assumption that virtually all the other 10883 do not reject–that is, they accept–AGW but I can’t say for sure that each one of them does.”


Article source: http://www.salon.com/2014/03/25/10853_out_of_10855_scientists_agree_man_made_global_warming_is_happening/

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)

March 25, 2014 by admin  
Filed under Featured, Global Warming

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

The last time Earth’s oceans were this acidic, a six mile-wide sulphur-rich space rock had just smashed into the Yucatan Peninsula, unleashing a deluge of acid rain that exterminated all sea life in the the top 400 meters of the water column. Now, some 65 million years after the Cretaceous extinction, human activity is threatening to similarly decimate the ocean’s ecosystem—this time, from the bottom up.

How the Oceans Went Out of Whack

Under natural conditions, carbon dioxide is continuously transferred between the ocean, atmosphere, and continents in a delicately balanced process known as the carbon cycle. CO2 is pulled from the atmosphere by photosynthetic plants, which form the base of both terrestrial and oceanic food webs. It’ then subsequently sequestered in sediment when those plants—as well as the animals that feed on them—die and decompose. It’s a nice trick and it helps keep us all breathing.

Simultaneously, a roughly equivalent amount of carbon enters the atmosphere due to air-sea gas exchanges, as well as the respiration of sedimentary microbes as they decompose dead organic matter. Along with the nitrogen and water cycles, this carbon cycle is one of the primary facilitators of life on Earth, constantly recycling the limited supply of carbon that forms the base of every organism alive today.

But since the dawn of the industrial revolution, human activity—specifically, burning coal to produce energy—has upended the balance of the carbon cycle. The concentration of CO2 in the atmosphere has jumped from 280 ppm prior to industrialization to nearly 400 ppm today. We’re pouring more CO2 into the atmosphere than the system can sequester. This excess of atmospheric greenhouse gas has not only resulted in global warming but wreaked havoc on the ocean’s chemistry as well.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

When carbon dioxide enters the ocean, it reacts with seawater to create carbonic acid. This acid in turn produces a secondary reaction, splitting into separate bicarbonate and hydronium ions, which lower the water’s pH level. The more CO2 present in the atmosphere, the more gets absorbed by the oceans, and the lower the water’s pH will become.

Current scientific estimates suggest that the oceans are absorbing roughly 25 percent of the CO2 we produce each year, with another 45 percent remaining trapped in the atmosphere, and the rest being absorbed by terrestrial plants. Between 1751 and 1994, the surface ocean pH has dropped from an estimated 8.25 to 8.14. That may not seem like much but remember pH is logarithmic, just like the Richter Scale, so a .11 decrease constitutes a 30 percent increase in acidity. And if acidification rates continue at their present pace, the pH of the world’s oceans could drop another .5 units—roughly triple the acidity they are right now—by 2100. This would be cataclysmic for sea life and humanity alike.

What This Means for Sea Life

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

While an added abundance of atmospheric C02 may be a boon to plant life, the resulting acidification it causes is seriously impairing the development of oceanic calcifying organisms—everything that lives in a calcium-based shell from the phytoplankton, zooplankton, and corals that form the base of the food web to mollusks and crustaceans like clams, oysters, crabs, and lobsters.

Normally, there’s a supersaturation of carbonate ions, which these animals process into aragonite for use in their shells. However, as the pH decreases, calcium carbonate becomes more soluble which reduces the concentration of available carbonate ions. And not only does this reduce the rate at which organisms can build their protective structures, it also increases the rate at which existing shells dissolve. They’re literally being melted away by increasingly corrosive seawater.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

And it’s not just shellfish that are at risk. Decreased pH levels have been linked to a number of other adverse effects—both direct and indirect—such as the CO2-induced acidification of body fluids, known as hypercapnia, the reduced metabolism in jumbo squid, slowed embryonic development in Atlantic longfin squid, the inability of juvenile clownfish (poor Nemo!) to hear and smell approaching predators, and the diminished echolocation capacity of dolphins and whales.

Nowhere, though, is the effect more clearly illustrated than in coral. Both tropical and deep sea coral species, whose calcium carbonate homes form reefs that support entire ecosystems—acting as both nurseries for a number of commercial fish stocks as well as habitat for countless other species—are showing slower rates of growth than in the past and are suffering from the effects of coral bleaching at unprecedented levels. In 2005, for example, nearly half of the coral around the Virgin Islands and Puerto Rico were lost in a single year to mass bleaching events.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

Image: Acropora

The loss of their coral homes only serves to amplify the pressure exerted on existing fish and crustacean populations from overfishing, habitat loss, pollution, and rising sea temperatures. It won’t be long before humanity is directly affected too.

What This Means for Humans

The ocean acts as the primary source of protein for over a billion people worldwide. The US commercial fishing industry exported more than $5.1 billion of fish products in 2012 alone while providing employment for more than a million Americans. We are the fifth-largest seafood producer behind China, Peru, India, and Indonesia—catching just 3.8 percent of the global total annually.

Ocean acidification threatens to topple this industry in the near term if steps are not taken to correct it. The populations of popular shellfish like lobsters, crab, scallops, shrimp, oysters, mussels, and clams are in danger of collapse as the concentration of carbonate ions continues to decline. What’s more, the increased water acidity is doing strange things to crab stocks.

How Global Warming Is Dissolving Sea Life (And What We Can Do About It)S

Image: Sasha Isachenko

Alaskan Red King Crabs—the centerpiece of the Alaskan crabbing industry, which fetched $92.5 million for just 14.8 million pounds in 2011—show a 100 percent increase in larval mortality (twice as many die) when raised in acidified water, though the less sought-after dungeness crabs, which live in the same areas as King Reds, are less unaffected by the pH change. Maryland Blue crabs, on the other hand, will grow three times their average size when raised in lower pH waters and become extremely aggressive predators. Still, should these populations collapse, the damage to the regional fishing industry—not to mention the prices at your supermarket—will take decades to repair.

What We Can Do About It?

Since ocean acidification (like global warming) is the result of human activity, it therefore can be mitigated by changing the way we interact with the environment.

One obvious answer is to simply reduce the amount of CO2 we’re discharging into the air, though that is far easier said than done. While the world’s governments continue t0 work towards a political solution (see: the Kyoto Protocol) and coastal fisheries simultaneously strive to both slow the rate of acidification and adapt to changing water chemistry, there are a number of steps individuals can take to reduce their carbon footprint. And while reducing your personal carbon emissions may not make a very big impact, the actions of 6 billion individuals taken together could very well save the world. [PhysOrg - Wiki 1, 2, 3 - NOAA 1, 2, 3, 4 - NRDC - WHOI - EPA - Seattle Times - Real Science]

top image: Ethan Daniels

Article source: http://gizmodo.com/how-global-warming-is-dissolving-sea-life-and-what-we-1532266705

Global warming not stopped, will go on for centuries - WMO

March 24, 2014 by admin  
Filed under Global Warming


GENEVA (Reuters) - There has been no reverse in the trend of global warming and there is still consistent evidence for man-made climate change, the head of the U.N. World Meteorological Organisation (WMO) said on Monday.

A slow-down in the average pace of warming at the planet’s surface this century has been cited by “climate sceptics” as evidence that climate change is not happening at the potentially catastrophic rate predicted by a U.N. panel of scientists.

But U.N. weather agency chief Michel Jarraud said ocean temperatures, in particular, were rising fast, and extreme weather events, forecast by climate scientists, showed climate change was inevitable for the coming centuries.

“There is no standstill in global warming,” Jarraud said as he presented the WMO’s annual review of the world’s climate which concluded that 2013 tied with 2007 as the sixth hottest year since 1850 when recording of annual figures began.

“The warming of our oceans has accelerated, and at lower depths. More than 90 percent of the excess energy trapped by greenhouse gases is stored in the oceans.

“Levels of these greenhouse gases are at a record, meaning that our atmosphere and oceans will continue to warm for centuries to come. The laws of physics are non-negotiable,” Jarraud told a news conference.

The 21-page survey said the global land and sea surface temperature in 2013 was 14.5 degrees Celsius (58.1 Fahrenheit), or 0.50C (0.90F) above the 1961-90 average. It was also 0.03C (0.05F) up on the average for 2001-2010.

The WMO’s Annual Statement on the Status of the Climate, pointed to droughts, heatwaves, rising seas, floods and tropical cyclones around the globe last year as evidence of what the future might hold.

FLUCTUATIONS

It was issued on the eve of a conference bringing climate scientists together with officials from over 100 governments in Japan from March 25-29 to approve a report on the effects of future global warming and how these might be mitigated.

A draft of this report, from the Intergovernmental Panel on Climate Change (IPCC), says global warming will disrupt food supplies, slow world economic growth and may already be causing irreversible damage to nature.

The chair of the IPCC, Rajendra Pachauri, told Reuters last week that the report made even more compelling the scientific arguments for a reduction in greenhouse gas emissions.

Some 200 countries have agreed to try to limit global warming to less than 2.0 degrees Celsius above pre-industrial times, largely by cutting emissions from burning fossil fuels like coal, oil and gas.

Sceptics argue that changes in global weather are the product of natural fluctuations or other natural causes.

But such arguments were rejected by Jarraud.

Natural phenomena like volcanoes or the El Nino/La Nina weather patterns originating in Pacific Ocean temperature changes had always framed the planet’s climate, affecting heat levels and disasters like drought and floods, he said.

“But many of the extreme events of 2013 were consistent with what we would expect as a result of human-induced climate change,” declared the WMO chief, pointing to the destruction wreaked by Typhoon Haiyan in the Philippines.

Another example was the record hot summer of 2012-13 in Australia which brought huge bush fires and destruction of property. Computer simulations showed the heat wave was 5 times as likely under human influence on climate, Jarraud said.

Among other extreme events of 2013 probably due to climate change were winter freezes in the U.S. south-east and Europe, heavy rains and floods in north-east China and eastern Russia, snow across the Middle East and drought in south-east Africa.

(Editing by Robin Pomeroy)

Article source: http://in.reuters.com/article/2014/03/25/climatechange-temperature-idINDEEA2O00620140325

Yes, Manmade Global Warming Is Worsening California’s Epic Drought

March 23, 2014 by admin  
Filed under Global Warming


By Joe Romm on

March 23, 2014 at 1:29 pm

California’s epic drought got even worse last week. The U.S. Drought Monitor reports that the area of California under moderate drought (or worse) rose from 94.6 percent of the state to a stunning 99.8 percent. The area under extreme or exceptional drought rose from 65.9 to 71.8 percent, encompassing the entire agriculture-rich Central Valley

Back in January, we interviewed 8 of the leading climate and drought experts in the country, who explained in great detail how climate change is worsening California’s epic drought in multiple ways. As I discussed in my 2011 literature review in the journal Nature — even in regions where climate change does not alter the amount of precipitation, it will have these effects:

What precipitation there is will probably come in extreme deluges, resulting in runoff rather than drought alleviation. Warming causes greater evaporation and, once the ground is dry, the Sun’s energy goes into baking the soil, leading to a further increase in air temperature…. Finally, many regions are expected to see earlier snowmelt, so less water will be stored on mountain tops for the summer dry season.

The president’s science advisor John Holdren made precisely the same points in a recent paper.

These points are disputed by very few. So why is there any confusion? A relatively small subset of experts are focused very narrowly on the issue of whether global warming caused a reduction in precipitation — but they generally fail to make clear how narrow their perspective is. NOAA’s Martin Hoerling did this in a recent New York Times piece, asserting “At present, the scientific evidence does not support an argument that the drought there is appreciably linked to human-induced climate change.”

Now, in fact, there is science supporting the argument that the reduction in precipitation is directly linked to human-induced climate change, specifically Arctic ice loss. I broke that story last June (see here) and updated it again in March.

But even setting aside the precipitation issue, our leading scientists have repeatedly made clear that global warming is worsening the drought. In a letter to the NY Times, three top drought experts — Peter Gleick, Jonathan Overpeck, and Connie Woodhouse — explain that the issue of what “caused” the drought “is the wrong question to ask”:

The current drought has certainly been exacerbated by climate change for one simple reason: Temperatures in California are now higher today, as they are globally. This alone increases water demand by crops and ecosystems, accelerates snowpack loss, and worsens evaporation from reservoirs. There are other complicating effects, but the influence of higher temperatures on drought is already real and cannot be ignored.

We are now unambiguously altering the climate, threatening water supplies for human and natural systems. This is but one example of how even today we are paying the cost of unavoidable climate changes.

As if to underscore this point, last week NOAA released its climate analysis of the U.S. winter, reporting:

California had its warmest winter on record…. The California winter temperature was 48.0°F, 4.4°F above the 20th century average, far exceeding the previous record, set in 1980/81, by 0.8°F.

And as Tamino explains, in California, “If we look at an actual measure of drought — the Palmer Drought Severity Index, or PDSI — then there is a decreasing trend (which means, toward more and/or more extreme drought) which is statistically significant.”

Finally, our favorite climate videographer Peter Sinclair has interviewed a variety of scientists on this subject in yet another must-see video:

Article source: http://thinkprogress.org/climate/2014/03/23/3417814/global-warming-california-drought/

Last edge of Greenland ice sheet to resist global warming is now unstable

March 17, 2014 by admin  
Filed under Global Warming

The last edge of the Greenland ice sheet that had resisted global warming has now become unstable, adding billions of tonnes of meltwater to rising seas, scientists said.

In a study published on Sunday in the journal Nature Climate Change, they said a surge in temperature from 2003 had eased the brakes on a long “river” of ice that flows to the coast in northeastern Greenland. Known as an ice stream, the “river” takes ice from a vast basin and slowly shifts it to the sea.

In the past, the flow from this ice stream had been constrained by massive buildups of ice debris choking its mouth. But a three-year spell of exceptionally high temperatures removed this blockage - and like a cork removed from a bottle helped accelerate the flow, the study said.

The stream, called Zachariae, is the largest drain from an ice basin that covers 16 per cent of the Greenland ice sheet.

From 2003 to 2012, northeastern Greenland disgorged 10 billion tonnes of ice annually into the ocean, the study found.

“Northeast Greenland is very cold. It used to be considered the last stable part of the Greenland ice sheet,” said Michael Bevis, an earth sciences professor at Ohio State University who led the study. “This study shows that ice loss in the northeast is now accelerating. So, now it seems that all the margins of the Greenland ice sheet are unstable.”

Greenland is estimated to contribute 0.5mm to the 3.2 mm annual rise in global sea levels.

The study’s main tool was data from a network of 50 Global Positioning System (GPS) sensors along the Greenland coast.

They use earth’s natural elasticity as a stethoscope of the ice sheet. When the ice melts in massive quantities the land rebounds and the sensor positions change.

To get a wider picture, the GPS data was then overlaid with data from four satellites that measured ice thickness from space.

“The Greenland ice sheet has contributed more than any other ice mass to sea level rise over the last two decades and has the potential, if it were completely melted to raise global sea level by more than seven metres,” said Jonathan Bamber, a professor at Britain’s University of Bristol.

Article source: http://www.scmp.com/news/world/article/1451095/last-edge-greenland-ice-sheet-resist-global-warming-now-unstable

EarthTalk: Global warming and your health

March 14, 2014 by admin  
Filed under Global Warming

Dear EarthTalk: How is it that global warming could cause an increase in health problems and disease epidemics? Do we have any evidence that it is already happening? — Jim Merrill, Provo, Utah

Global warming isn’t just bad for the environment. There are several ways that it is expected to take a toll on human health. For starters, the extreme summer heat that is becoming more normal in a warming world can directly impact the health of billions of people.

“Extreme high air temperatures contribute directly to deaths from cardiovascular and respiratory disease, particularly among elderly people,” reported the World Health Organization. “In the heat wave of summer 2003 in Europe, for example, more than 70,000 excess deaths were recorded.”

WHO added that high temperatures also play a role in elevated levels of ozone and other air pollutants known to exacerbate respiratory and cardiovascular problems. And according to the nonprofit Union of Concerned Scientists, warmer temperatures and higher levels of atmospheric carbon dioxide can stimulate plants to grow faster, mature earlier and produce more potent allergens.

“Common allergens such as ragweed seem to respond particularly well to higher concentrations of carbon dioxide, as do pesky plants such as poison ivy,” the group reported. “Allergy-related diseases rank among the most common and chronic illnesses.”

Another way global warming is bad for our health is that it increases extreme weather events that can injure or kills large numbers of people. According to WHO, the number of weather-related natural disasters has more than tripled since the 1960s. Likewise, increasingly variable rainfall patterns combined with higher overall temperatures are leading to extended droughts around the world.

“By the 2090s, climate change is likely to widen the area affected by drought, double the frequency of extreme droughts and increase their average duration six-fold,” reported WHO. One result is likely to be a downturn in agricultural productivity along with a spike in malnutrition. Another is less access to safe drinking water, a trigger for poor sanitation and the spread of diarrheal diseases — not to mention resource wars.

Perhaps most worrying to public health experts, though, is the potential for global warming to cause a spike in so-called “vector-borne diseases” like schistosomiasis, West Nile virus, malaria and dengue fever.

“Insects previously stopped by cold winters are already moving to higher latitudes” toward the poles, UCS reported. Researchers predict that thanks to global warming an extra two billion people, mostly in developing countries, will be exposed to the dengue virus over the next half century.

A related fear is that thawing permafrost in polar regions could allow otherwise dormant age-old viruses to re-emerge. This year, French and Russian researchers discovered a 30,000 year old giant virus, previously unknown to science, in frozen soil in Russia’s most northerly region. While the virus, which researchers dubbed Pithovirus sibericum, is harmless to humans and animals, its discovery has served as a wake-up call to epidemiologists about the potential re-emergence of other viruses that could make many people sick. While some of these re-emergent viruses might also be new to science, others could be revitalized versions of ones we thought we had eradicated, such as smallpox.

Contacts: WHO, www.who.int; UCS, www.ucsusa.org.

EarthTalk is by Roddy Scheer and Doug Moss of E — The Environmental Magazine (www.emagazine.com). Send questions to earthtalk@emagazine.com.

Article source: http://www.dariennewsonline.com/news/article/EarthTalk-Global-warming-and-your-health-5320101.php

Global Warming Slows Antarctica’s Coldest Currents

March 5, 2014 by admin  
Filed under Global Warming

A shift from briny to fresh in Antarctica’s ocean waters in recent decades could explain the shutdown of the Southern Ocean’s coldest, deepest currents, a new study finds.

The cold currents, called the Antarctic Bottom Water, are chilly, salty rivers that flow from the underwater edge of the Antarctic continent north toward the equator, keeping to the bottom of the seafloor. The currents carry oxygen, carbon and nutrients down to the deepest parts of the ocean. Previous studies have found this deep, dense water is disappearing, though researchers aren’t sure if the shrinkage is part of a long-term trend linked to global warming, or a natural cycle.

The new study suggests that Antarctica’s changing climate is to blame for the shrinking Antarctica Bottom Water. In the past 60 years, the ocean surface offshore Antarctica became less salty as a result of melting glaciers and more precipitation (both rain and snow), researchers reported Sunday (March 2) in the journal Nature Climate Change. This growing freshwater layer is the key link in a chain that prevents the cold-water currents from forming, the study finds.

“Deep ocean waters only mix directly to the surface in a few small regions of the global ocean, so this has effectively shut one of the main conduits for deep-ocean heat to escape,” said Casimir de Lavergne, an oceanographer at McGill University in Montreal.

Holey ice

The linchpins linking freshwater and cold currents are polynyas, or natural holes within sea ice. These persistent regions of open water form when upwellings of warm ocean water keep water temperatures above freezing, or when winds drive sea ice away from the coast.

Polynyas are one of the main sources of Antarctica Bottom Water. Polynyas act like natural refrigerators, letting frigid temperatures and cold winds chill seawater and send it sinking down to the ocean bottom. As the cold water sinks, warmer ocean water comes up to take its place, maintaining the polynya’s open water. [Album: Stunning Photos of Antarctic Ice]

But as Antarctica’s ocean surface water has freshened, fewer polynyas have appeared, the researchers found. That’s because the fresher water is less dense. Even if the water is very cold, it doesn’t sink as readily as saltier water, de Lavergne explained. The freshwater acts like a lid, shutting down the ocean circulation that sends cold water to the seafloor, and brings up warm water into the polynyas.

“What we suggest is, the change in salinity of the surface water makes them so light that even very strong cooling is not sufficient to make them dense enough to sink,” de Lavergne told Live Science. “Mixing them gets harder and harder.”

Trapped heat

In addition to warming and shrinking the Antarctic Bottom Water currents, the reduction in polynyas could be trapping extra heat in the Southern Ocean, de Lavergne said.

“If the warm waters aren’t able to release their heat to the atmosphere, then the heat is waiting in the deep ocean instead,” he said. “This could have slowed the rate of warming in the Southern Hemisphere.”

De Lavergne cautioned that the heat-storage effect is localized and not related to the so-called global warming “hiatus” — the recent slowdown in the rise of global surface temperatures.

“Our study is still a hypothesis,” he added. “We say that climate change is preventing convection from happening, but we do not know how frequent it was in the past, so that’s a big avenue for future research.”

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Article source: http://www.scientificamerican.com/article/global-warming-slows-antarcticas-coldest-currents/

Calcium, building block for the world

March 4, 2014 by admin  
Filed under Global Warming

It’s the fifth most abundant element on earth - and the world’s building block. Do we fully appreciate the value of calcium?

Most of us are familiar with the idea that our bodies need calcium. I remember being told to drink up my milk because the calcium in it would make my bones strong.

And calcium is indeed the key element in our bones. In fact, it is the most abundant metal in the human body - and in those of most other animals too.

Many organisms use calcium to build the structures that house and support them - skeletons, egg shells, mollusc shells, coral reefs and the exoskeletons of krill and other marine organisms.

And calcium is also the key ingredient in man’s most important structural material - cement.

These days virtually all our architecture, all our great building and engineering projects start with calcium, because cement is the basis of the most widely used man-made substance on earth - concrete.

Fortunately there’s a lot of calcium about - the soft grey metal is the fifth most abundant element in the earth’s crust.

There is plenty dissolved in the sea. For millennia, marine organisms have been combining it with carbon dioxide they fix from the atmosphere to make shells of calcium carbonate.

When they die, their shells and skeletons sink down to the bottom of the sea and collect in great drifts. Over millions of years they have been compacted to form limestone, chalk and marble.

Continue reading the main story

Calcium - key facts

  • Found in sedimentary rocks, including limestone, and minerals such as calcite, dolomite and gypsum
  • Comes from Latin word calx (lime)
  • Used in the making of cement and cheese
  • Pure calcium is a silvery metal, a little harder than lead

When you get the chance, take a close look at a piece of limestone. You’ll probably see the tiny fossils of the ancient marine creatures of which it is composed.

Some 10% of all sedimentary rock is limestone, which is pretty extraordinary when you consider that it represents the concentrated bodily remains of living creatures.

So how do we get from limestone to concrete?

The key is extracting the calcium from limestone. It’s a trick mankind learned very early on.

In principle the process is pretty simple - you just need to heat limestone up.

What you do is place your limestone - calcium carbonate - in a fire where the temperatures are high enough to drive out the carbon atoms as carbon dioxide into the atmosphere. That leaves you with calcium oxide - more commonly known as lime.

Lime is the basis of most cements - the glue that hold rocks and particles of sand together to make concrete.

Recent archaeological discoveries show some prehistoric people created concrete, even before they’d discovered the first metals.

Over the last two decades, a German archaeologist working in Turkey has uncovered what he believes is the world’s first temple. It is a complex of carved stones erected about 11,000 years ago - 6,000 years before Stonehenge.

An early “concrete” was used on the Pont du Gard, constructed out of soft yellow limestone blocks

The site is called Gobekli Tepe - Pot-bellied Hill in Turkish - and features floors made of very early cements.

The technology was refined over the millennia. Two magnificent Roman buildings, the Pantheon and the Pont du Gard at Nimes, showed the potential of concrete.

They used it to enclose space with an unsupported dome, and to bridge considerable spans without reinforcement.

Continue reading the main story

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Nevertheless, these early concretes remained brittle and weak, which is why most buildings continued to be made of stone and brick.

The breakthrough came in the 1840s.

On a rainy February afternoon I went to see the site of this momentous advance. It could hardly be less cherished.

I had an expert guide in Edwin Trout, the chief archivist of the Concrete Society. We met outside WE Roberts’ cardboard box factory on the banks of the Thames Estuary in Kent. Our destination lay deep within the factory complex.

We were led down an alleyway between two big buildings and in through a low door.

We had to duck under a cardboard corrugating machine - a surprisingly large contraption - and then through a door in the wall of the factory.

Portland cement was created inside a bottle kiln

It opened out on to a small courtyard almost entirely taken up by a looming brick structure. It was hard to get a good view, because it was surrounded on all sides by the walls of the factory. Nevertheless, it was clear that Edwin was excited by what he was seeing.

“Portland cement was first developed at this site by a chap called William Aspdin,” he told me.

The brick circular structure, he explained, is one of the earliest kilns used to produce this new cement.

It is known as a bottle kiln, because of its shape, and it was here that Aspdin experimented - burning the limestone by baking it with clay at the then unthinkable temperature of 1450C. The result was a solid amalgam of the two materials known as “clinker”.

Aspdin discovered that when this was ground to a fine powder, it produced an exceptionally powerful cement. And very soon, he got the perfect opportunity to test out his new product.

It came about because of what became known as “The Big Stink”.

At the time, the Thames was essentially an open sewer. The booming population of London, the spread of industry, and the development of the flush toilet, all meant the volume of waste flowing into the river had risen dramatically.

In the hot summer of 1858, the stench became unbearable and there was a public outcry. The London boroughs finally agreed to commission the great network of new sewers that had been proposed by the visionary engineer Joseph Bazalgette.

The builders performed rigorous tests of the various cements on the market in order to choose the very best one for their vast scheme - the greatest public works project ever undertaken.

Portland cement, Edwin Trout tells me proudly, won easily. It was, he says, “stronger, more durable and - by that stage - more widely available too”.

And it is a testament to the strength of the cement - and the power of calcium - that, 150 years later, Londoners are still using the sewers Bazalgette built to flush away their waste.

Indeed, the incredibly strong concrete Portland cement creates has transformed the building industry across the world - as the skyline of every major city shows.

The world produces about 3.5bn tonnes of cement a year. Given that cement is usually between 10% and 15% of the mix in concrete, that’s enough cement to produce about four tonnes of concrete for every person on earth each year.

The problem is that creating all the cement for all that concrete is doubly polluting.

You need vast amounts of energy to get your kiln hot enough to bake all that limestone, and that usually means burning fossil fuels. And the limestone itself produces vast amounts of greenhouse gases, as all the carbon dioxide fixed by those ancient sea creatures is driven into the atmosphere.

Every ton of cement produces almost a ton of CO2. That’s why the concrete industry is reckoned to be one of the most polluting on earth, responsible for up to 5% of total CO2 emissions.

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Article source: http://www.bbc.co.uk/news/magazine-26416749

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