Tag: sea level

Can climate change affect volcanic activity?

Vesuvius is part of a volcanic region that became more active when the Mediterranean Sea dried up about 5 million years ago. A study of the era suggests climate change can influence volcanic activity. @bberwyn photo.

Study suggests link between sea level and eruptions

Staff Report

European researchers say they’ve found more evidence supporting links between climate change and volcanic activity.

Geologists from Switzerland, France and Spain studied compared data on eruptions and climate from about 5 million years ago, finding that volcanic activity in southern Europe doubled during a time when the Mediterranean Sea dried up. They suspect that the changes on the surface contributed to the way magma behaves deep in the Earth.

The era they studied is known as the Messinian salinity crisis, when the Strait of Gibraltar was blocked and the Mediterranean temporarily isolated from the Atlantic, according to the study published in Nature Geoscience.

The geological record shows a sharp increase in volcanic activity, and the scientists concluded the spike can best be explained by the almost total drying out of the Mediterranean.

The trait of Gibraltar was shut on a temporary basis during the Messinian Era (from 5.96 to 5.33 million years ago) and that the Mediterranean Sea was isolated from the Atlantic. Thick layers of salt on the seabed, as well as river canyons carved through land that is now submerged, suggest the Mediterranean Sea’s level was much lower.

The study acknowledges that this hypothesis continues to be a source of debate, while exploring the potential links.

In a statement, University of Geneva geologist Pietro Sternai said it’s clear that changes at the surface of the Earth, like a sudden lowering of sea level, can change the pressure deep down around pockets of molten magma. Based on that, the researchers studied the changes in volcanic activity during the period. Tracing the age of crystals in volcanic deposits, they counted 13 eruptions around the Mediterranean between 5.9 and 5.3 million years ago — more than double the average over comparable time periods.

Why is the figure so high?

“The single logical explanation is the hypothesis that the sea dried out, since this is the only event powerful enough to alter the Earth’s pressure and magmatic production over the entire Mediterranean,” Sternai said.

The team used computer models to simulate the effect of the Mediterranean’s desiccation on pressure at depth and the impact on magma production. According to Sternai, the models show the only way to account for the increased vulcanism was that the level of the Mediterranean Sea dropped by about two kilometres.

Related research has suggested that melting ice sheets in the polar regions, as well as melting glaciers, could also contribute in various ways to increased volcanic activity.

 

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Arctic warmup speeds Canada glacier meltdown

Between 2005 to 2015, surface melt off ice caps and glaciers of the Queen Elizabeth Islands grew from an average of three gigatons to 30 gigatons

The Canadian Rockies near Kelowna, partially shrouded by pop-up clouds and haze.
Canadian glaciers are melting and have become a significant factor in global sea level rise. @bberwyn photo

Staff Report

The Greenland Ice Sheet isn’t the only place melting under a thickening blanket of heat-trapping greenhouse gases. A new study shows that Canada’s Arctic glaciers are also shedding ice at a rapidly increasing rate, making them a big factor in global sea level rise.

In a new study, glaciologists with the University of California, Irvine  said that, between 2005 to 2015, surface melt off ice caps and glaciers of the Queen Elizabeth Islands grew by 900 percent, from an average of three gigatons to 30 gigatons per year, according to findings published last week in the journal Environmental Research Letters. Continue reading “Arctic warmup speeds Canada glacier meltdown”

Study says ice sheets can crumble quickly

Slight ocean warming enough to tip the system

Scientists working in Greenland have been stunned by the speed at which ice is retreating.
Retreating ice shows dramatic climate change is under way in the Anthropocene. @bberwyn photo.

Staff Report

Just small increases in ocean temperatures during past geological epochs may have been enough to tip Northern Hemisphere ice sheets toward disintegration, even as air temperatures remained cold. That could spell trouble in the current era of climate warming, according to a new study led by University of Michigan researchers, who said their finding suggest that climate change could cause sea level to rise higher than most models predict. Continue reading “Study says ice sheets can crumble quickly”

What’s driving the collapse of Antarctic ice shelves?

New CSU study eyes regional climate cycle as one factor

Disintegration of ice shelves in East Antarctica could result in a spiraling increase in sea levels. PHOTO BY BOB BERWYN.
Disintegration of ice shelves in East Antarctica has been linked with a regional climate pattern and could result in a spiraling increase in sea levels. @bberwyn photo.

Staff Report

This year’s rapid loss of sea ice around Antarctica may make the floating ice shelves along the coast of the continent even more vulnerable to collapse, and a  Hemisphere climate cycle known as the Southern Annular Mode is probably a factor in the equation.

Just during the past 50 years, more than 28,000 square kilometers of ice shelves have crumbled along the Antarctic Peninsula, and one of the last remaining large ice shelves looks set to shed another piece about as large as Delaware. A new study led by Colorado State University scientists offers some new information on climate processes in the region. Continue reading “What’s driving the collapse of Antarctic ice shelves?”

Ocean layering around Antarctica could signal major meltdown

Study warns of 10-foot sea level rise

Sunlit icebergs gleam on the horizon in the Antarctic Sound.
Antarctica could be closer to a meltdown than previously thought. @bberwyn photo.

Staff Report

As scientists learn more about the dynamics of the ocean around Antarctica, they’ve discovered a climate warming signal. Distinct layers of water, marked by temperature boundaries, are forming right now, leading to conditions similar to about 14,000 years ago, when Antarctic ice sheets melted rapidly, raising global sea level by more than 10 feet. Continue reading “Ocean layering around Antarctica could signal major meltdown”

What’s the tipping point for Antarctica’s ice sheets?

New study suggests rapid meltdown during post-ice age warming

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How long will it take for Antarctica’s ice sheets to melt? @bberwyn photo.

Staff Report

After taking a close look at rocks from West Antarctica’s dramatic Ellsworth Mountains, climate researchers say there’s a chance that ice sheets in the region could melt quickly as the planet warms, potentially causing sea level to rise by  six to eight feet.

The new study, published in Nature Communications, took a close look at Antarctic climate change about 21,000 years ago during a period of warming after the coldest point of the most recent Ice Age. They found that  the West Antarctic Ice Sheet reached a tipping point, after which it thinned relatively quickly, losing 400m of thickness in 3,000 years. Continue reading “What’s the tipping point for Antarctica’s ice sheets?”

Annual atmospheric CO2 increase the biggest on record

Far, far away from 350 ppm …

Atmospheric carbon dioxide in February 2016 measured at Mauna Loa.
Atmospheric carbon dioxide in February 2016 measured at Mauna Loa.

Staff Report

The goal of limiting atmospheric carbon dioxide to 350 parts per million — considered the environmentally “safe” level, just moved a little farther away. Scientists tracking concentrations of the heat-trapping pollutant at a mountaintop lab in Hawaii said last week that CO2 concentrations jumped by the largest annual amount recorded since measurements began 56 years ago.

The reading comes from NOAA’s Mauna Loa Observatory, and researchers said the latest increase was the fourth year in a row that CO2 concentrations grew by more than 2 parts per million, according to a press release from NOAA.

“Carbon dioxide levels are increasing faster than they have in hundreds of thousands of years,” said Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network. “It’s explosive compared to natural processes.” Continue reading “Annual atmospheric CO2 increase the biggest on record”