Iceland volcano ash unlikely to cool planet, says Australian climatologist

Melbourne, April 19 (ANI): An Australian climatologist has said that the volcanic ash cloud that exploded from an Icelandic volcano is unlikely to have an impact on global temperatures.

The volcano, which is located under the Eyjafjallajokull glacier, had erupted on April 15, producing a 10-kilometre high plume of ash and rock that extended across most of northern Europe.

And while the particles may have a short-term effect on the local temperature, experts believe that it will not have the same impact as the Pinatubo eruption did two decades earlier.

In June 1991, Mount Pinatubo, an active volcano in the Philippines, launched ten cubic kilometres of material into the atmosphere.

Particles from the eruption entered the Earth”s stratosphere resulting in a 10 percent reduction in sunlight reaching the Earth”s surface, and a 0.4°C drop in global average temperatures.

Dr Blair Trewin of the National Climate Centre in Melbourne says, in its current form the ash cloud is unlikely to have the same impact on global temperatures.

“For a volcano to have a significant global cooling effect it has to get its ash up into the stratosphere,” ABC Science quoted him as saying.

“If it doesn”t, the ash will get rained out fairly quickly,” he said.

But he said that even if the particles managed to reach the stratosphere, the location of the volcano will mean the ash will likely stay in the northern hemisphere.

“Once you”re in the stratosphere the winds tend to flow out from the equator to the poles,” Trewin said.

“So if you get a big eruption in the tropics the winds in the stratosphere will tend to spread out material over the whole globe.

“Whereas if it happens in the polar regions the stuff tends to get stuck – it doesn”t spread up to lower latitudes,” he stated.

Trewin says the volcanic ash cloud may have an impact locally.

“When Mount St Helens erupted in 1980 it had no significant global impacts, but in the days immediately after the eruption you had cooling of daylight temperatures by 10°C or more in some parts of the northwestern United States,” he revealed.

Dr Jeff Masters, Director of Meteorology at Weather Underground says the eruption isn”t expected to have a significant impact on weather patterns in the northern hemisphere.

“However, the ash could bring spectacular sunsets to Europe over the next week, and to North America by sometime next week, as the jet stream wraps the ash cloud eastwards across the northern hemisphere,” he added. (ANI)

Iceland volcano ash unlikely to cool planet, says Australian climatologist

Melbourne, April 19 (ANI): An Australian climatologist has said that the volcanic ash cloud that exploded from an Icelandic volcano is unlikely to have an impact on global temperatures.

The volcano, which is located under the Eyjafjallajokull glacier, had erupted on April 15, producing a 10-kilometre high plume of ash and rock that extended across most of northern Europe.

And while the particles may have a short-term effect on the local temperature, experts believe that it will not have the same impact as the Pinatubo eruption did two decades earlier.

In June 1991, Mount Pinatubo, an active volcano in the Philippines, launched ten cubic kilometres of material into the atmosphere.

Particles from the eruption entered the Earth”s stratosphere resulting in a 10 percent reduction in sunlight reaching the Earth”s surface, and a 0.4°C drop in global average temperatures.

Dr Blair Trewin of the National Climate Centre in Melbourne says, in its current form the ash cloud is unlikely to have the same impact on global temperatures.

“For a volcano to have a significant global cooling effect it has to get its ash up into the stratosphere,” ABC Science quoted him as saying.

“If it doesn”t, the ash will get rained out fairly quickly,” he said.

But he said that even if the particles managed to reach the stratosphere, the location of the volcano will mean the ash will likely stay in the northern hemisphere.

“Once you”re in the stratosphere the winds tend to flow out from the equator to the poles,” Trewin said.

“So if you get a big eruption in the tropics the winds in the stratosphere will tend to spread out material over the whole globe.

“Whereas if it happens in the polar regions the stuff tends to get stuck – it doesn”t spread up to lower latitudes,” he stated.

Trewin says the volcanic ash cloud may have an impact locally.

“When Mount St Helens erupted in 1980 it had no significant global impacts, but in the days immediately after the eruption you had cooling of daylight temperatures by 10°C or more in some parts of the northwestern United States,” he revealed.

Dr Jeff Masters, Director of Meteorology at Weather Underground says the eruption isn”t expected to have a significant impact on weather patterns in the northern hemisphere.

“However, the ash could bring spectacular sunsets to Europe over the next week, and to North America by sometime next week, as the jet stream wraps the ash cloud eastwards across the northern hemisphere,” he added. (ANI)

Volcanic ash unlikely to cool planet

The volcanic ash cloud that exploded from an Icelandic volcano this week is not expected to have an impact on global temperatures, says an Australian climatologist.

The volcano, located under the Eyjafjallajokull glacier, erupted on Thursday producing a 10-kilometre high plume of ash and rock that has extended across most of northern Europe.

The debris has caused the closure of airports in the UK, Norway, Denmark, Belgium and Sweden, and produced spectacular sunsets in the region.

While the particles may have an effect on local temperatures in the short-term, experts don’t believe it will have the same impact as the Pinatubo eruption two decades earlier.

In June 1991, Mount Pinatubo, an active volcano in the Philippines, launched ten cubic kilometres of material into the atmosphere.

Particles from the eruption entered the Earth’s stratosphere resulting in a 10% reduction in sunlight reaching the Earth’s surface, and a 0.4°C drop in global average temperatures.

Too low to make an impact

Dr Blair Trewin of the National Climate Centre in Melbourne says, in its current form the ash cloud is unlikely to have the same impact on global temperatures.

“For a volcano to have a significant global cooling effect it has to get its ash up into the stratosphere,” he says. “If it doesn’t, the ash will get rained out fairly quickly.”

Even if the material reaches the stratosphere, Trewin believes the volcano’s location will result in the ash staying in the northern hemisphere.

“Once you’re in the stratosphere the winds tend to flow out from the equator to the poles,” he says. “So if you get a big eruption in the tropics the winds in the stratosphere will tend to spread out material over the whole globe.

“Whereas if it happens in the polar regions the stuff tends to get stuck – it doesn’t spread up to lower latitudes.”

But Trewin says the volcanic ash cloud may have an impact locally.

“When Mount St Helens erupted in 1980 it had no significant global impacts, but in the days immediately after the eruption you had cooling of daylight temperatures by 10°C or more in some parts of the northwestern United States.”

Dr Jeff Masters, Director of Meteorology at Weather Underground says the eruption isn’t expected to have a significant impact on weather patterns in the northern hemisphere.

“However, the ash could bring spectacular sunsets to Europe over the next week, and to North America by sometime next week, as the jet stream wraps the ash cloud eastwards across the northern hemisphere.”

Indonesian supervolcano’s eruption caused decade of fatal winters 74,000 years ago

Washington, July 4 (ANI): Climate model simulations by a team of scientists has suggested that Indonesia’s Toba supervolcano, when it erupted about 74,000 years ago, triggered a 1,000-year episode of ice sheet advance, and also may have produced a short-lived “volcanic winter”, which drastically reduced the human population at the time.

Previous climate model simulations of the eruption have been unable to produce the glaciation, and there are no climate observations to support the volcanic winter.

To investigate additional mechanisms that may have enhanced and extended the effects of the Toba eruption, as well as the volcanic winter, Alan Robock and his team from Rutgers University, US, have conducted six climate model simulations using state-of-the-art models that include vegetation death effects on radiation budgets, and stratospheric chemistry feedbacks that might affect the lifetime of the volcanic cloud.

The researchers used a wide variety of aerosol injection volumes, ranging from 33 to 900 times that of the 1991 Mount Pinatubo injection.

They found that none of the models initiate glaciation.

Nonetheless, they produce a decade of severe volcanic winter, which would likely have had devastating consequences for humanity and global ecosystems, supporting the idea that the Toba eruption produced a genetic bottleneck in human evolution. (ANI)

Atmospheric engineering scheme to fight global warming could diminish solar power

Washington, April 20 (ANI): A new study has determined that a widely discussed “atmospheric engineering” scheme intended to combat global warming could have unanticipated consequences in reducing the effectiveness of certain kinds of solar power around the Earth.

In the study, the National Oceanographic and Atmospheric Administration’s Daniel M. Murphy examines a proposal to minimize climate change by enhancing the stratospheric aerosol layer, which reduces sunlight to Earth by scattering it to outer space.

But, this approach has considerable implications on the ability to concentrate solar power, according to Murphy.

For example, the increased aerosols resulting from the 1991 eruption of Mt. Pinatubo in the Philippines reduced global sunlight by less than three percent but decreased output from some solar generating plants by about 20 percent.

Murphy’s study found that aerosols reduce direct sunlight – the kind that casts shadows – much more than total sunlight.

Each one percent reduction in the Earth’s sunlight due to aerosols will cause a four to 10 percent loss in output from concentrating solar power applications.

He notes, however, that flat solar hot water and photovoltaic panels – which utilize both direct and diffuse (scattered) sunlight – will have smaller performance losses than concentrating solar collectors.

“One consequence of deliberate enhancement of the stratospheric aerosol layer would be a significant reduction in the efficiency of solar power generation systems,” said Murphy.

“Any cooling of the Earth that relies on light scattering, including tropospheric aerosol scattering and increased cloudiness, by particles will also result in reductions in direct sunlight that are several times the reductions in total sunlight,” he added. (ANI)

Swirling volcano plumes can spawn tornadoes and sheet lightning

London, March 30 (ANI): In a new research, scientists have found that Volcano plumes can swirl like cyclones, thus spawning tornadoes and sheet lightning.

It is conventionally thought that a volcanic plume rises straight up and spreads out in a rough circle.

But, according to a report in New Scientist, when Pinaki Chakraborty at the University of Illinois at Urbana-Champaign and colleagues studied hourly satellite photos of the 1991 eruption of mount Pinatubo in the Philippines, they noticed that the margins gradually separated into five lobes.

They saw similar shapes in photos of five other volcanoes.

The team’s calculations show that this is caused by anticlockwise rotation in the plume, which creates a centrifugal force that throws the lobes outwards.

The rotation occurs due to interactions between the updraught of the plume and horizontal wind patterns.

Such rotation may be the driving force behind small tornadoes and waterspouts seen near plumes, which would form in the same way as dust devils around a thunderstorm.

It may also explain the “sheaths” of lightning spotted in the 2008 eruption of mount Chaiten in Chile, because the cyclonic motion throws charged particles to the plume margins. (ANI)

Reduction in airborne dust responsible for recent warming trend in Atlantic Ocean

Washington, March 27 (ANI): A new study has determined that the recent warming trend in the Atlantic Ocean is largely due to reductions in airborne dust and volcanic emissions during the past 30 years.

Since 1980, the tropical North Atlantic has been warming by an average of a quarter-degree Celsius (a half-degree Fahrenheit) per decade.

“Though this number sounds small, it can translate to big impacts on hurricanes, which thrive on warmer water,” said Amato Evan, a researcher with the University of Wisconsin-Madison’s Cooperative Institute for Meteorological Satellite Studies and lead author of the new study.

For example, the ocean temperature difference between 1994, a quiet hurricane year, and 2005′s record-breaking year of storms, was just one degree Fahrenheit.

More than two-thirds of this upward trend in recent decades can be attributed to changes in African dust storm and tropical volcano activity during that time, report Evan and his colleagues at the UW-Madison and the National Oceanic and Atmospheric Administration.

In the new study, they combined satellite data of dust and other particles with existing climate models to evaluate the effect on ocean temperature.

They calculated how much of the Atlantic warming observed during the last 26 years can be accounted for by concurrent changes in African dust storms and tropical volcanic activity, primarily the eruptions of El Chichon in Mexico in 1982 and Mount Pinatubo in the Philippines in 1991.

In fact, it is a surprisingly large amount.

“A lot of this upward trend in the long-term pattern can be explained just by dust storms and volcanoes,” said Evans.

“About 70 percent of it is just being forced by the combination of dust and volcanoes, and about a quarter of it is just from the dust storms themselves,” he added.

The result suggests that only about 30 percent of the observed Atlantic temperature increases are due to other factors, such as a warming climate.

While not discounting the importance of global warming, Evan said that this adjustment brings the estimate of global warming impact on Atlantic more into line with the smaller degree of ocean warming seen elsewhere, such as the Pacific.

“This makes sense, because we don’t really expect global warming to make the ocean temperature increase that fast,” he said. (ANI)

Atmospheric ‘sunshade’ could reduce solar power generation

Washington, March 12 (ANI): A new study has suggested that the concept of delaying global warming by adding particles into the upper atmosphere to cool the climate could unintentionally reduce peak electricity generated by large solar power plants by as much as one-fifth.

The study was conducted by researchers at the National Oceanic and Atmospheric Administration (NOAA).

“Injecting particles into the stratosphere could have unintended consequences for one alternative energy source expected to play a role in the transition away from fossil fuels,” said Daniel Murphy, a scientist at NOAA’s Earth System Research Laboratory in Boulder, Colorado.

The Earth is heating up as fossil-fuel burning produces carbon dioxide, the primary heat-trapping gas responsible for man-made climate change.

To counteract the effect, some geoengineering proposals are designed to slow global warming by shading the Earth from sunlight.

Among the ideas being explored is injecting small particles into the upper atmosphere to produce a climate cooling similar to that of large volcanic eruptions, such as Mt. Pinatubo’s in 1991.

Airborne sulfur hovering in the stratosphere cooled the Earth for about two years following that eruption.

Murphy found that particles in the stratosphere reduce the amount and change the nature of the sunlight that strikes the Earth.

Though a fraction of the incoming sunlight bounces back to space (the cooling effect), a much larger amount becomes diffuse, or scattered, light.

On average, for every watt of sunlight the particles reflect away from the Earth, another three watts of direct sunlight are converted to diffuse sunlight.

Large power-generating solar plants that concentrate sunlight for maximum efficiency depend solely on direct sunlight and cannot use diffuse light.

Murphy verified his calculations using long-term NOAA observations of direct and diffuse sunlight before and after the 1991 eruption.

After the eruption of Mt. Pinatubo, peak power output of Solar Electric Generating Stations in California, the largest collective of solar power plants in the world, fell by up to 20 percent, even though the stratospheric particles from the eruption reduced total sunlight that year by less than 3 percent.

“The sensitivity of concentrating solar systems to stratospheric particles may seem surprising,” said Murphy. “But because these systems use only direct sunlight, increasing stratospheric particles has a disproportionately large effect on them,” he added. (ANI)

Greenland warming lags, but bound to catch up in future

Washington, Feb 28 (ANI): A new study has suggested that Greenland is lagging behind rest of the northern hemisphere’s warming trend and that it’s bound to catch up soon.

Air temperatures have been rising steadily in the northern half of the planet since about 1975, when scientists think the effects of human-induced global warming began to dominate the climate.

But, Greenland was left behind, perhaps kept cool when dust released from the eruptions of Mount St. Helens, El Chicon and Mt. Pinatubo reduced the amount of sunlight hitting the ice.

Around 1985, the icy island started to thaw, and has continued apace ever since.

Climate scientists have been alarmed by the speed of the melting, watching as glaciers recede and meltwater pools in lakes on top of the ice.

Now, according to a report in Discovery News, in an analysis of temperature records in Greenland from 1840 until 2007, Jason Box of Ohio State University and a team of researchers found that the ice sheet remains between 1.0 and 1.5 degrees Centigrade behind the rest of the northern hemisphere.

They also determined that it should catch up in the coming decades.

“The temperature increase could be three to four times what we’ve seen already. If that holds it will be far above anything we’ve seen before,” said David Bromwich of Ohio State University. “The ice will continue melting and probably accelerate in the future,” he added.

If Greenland’s ice sheet ever melts entirely, the results would be catastrophic.

The water unleashed into the ocean would be enough to raise sea level 6.5 meters (21.3 feet), jeopardizing the homes and lives of hundreds of millions of people worldwide.

Though that’s not likely to happen any time soon, Greenland is already starting to look slushy, and an additional degree or two of warming could be dangerous.

“We’ve said (in a previous study) that if you sustain between 2 and 7 degrees (3.6 to 12.6 Fahrenheit) of warming, Greenland’s ice will be gone,” said Richard Alley of Pennsylvania State University.

“It’s already warmed a good chunk of one degree, so if you add another 1-1.5 on top of that, you’re at the low end of really worry, and a lot closer to the upper end, too,” he added. (ANI)