by Peter Sinclair, cross-posted from the Climate Denial Crock of the Week

Since we have such an active community of armchair oceanographers and spreadsheet Glaciologists here, I thought it would be useful to speak to the real thing, the people who actually spend time on the ocean, on the ice sheets, do the measurements, and come back to share that knowledge with us. I had just that opportunity at the American Geophysical conference in December.

I spoke to Josh Willis, Oceanographer with NASA at the Jet Propulsion Lab. Josh is one of best known young ocean scientists on the planet. He pointed me to the recent Kemp et al study of tidal marshes on the US East coast, which has produced a long record of sea level over the last 2000 years, complete with a very Hockey-stickish uptick during the last 200 or so.

[JR:  For more on that study, see "NSF Study: Fastest Sea-Level Rise in Two Millennia Linked to Increasing Global Temperatures."]

Jason Box of the Byrd Polar Center at Ohio State was there, presenting evidence of acceleration in Greenland ice loss over the last 200 years. His bottom line: “If we talk 10 years from now, my expectation is that Greenland will be losing roughly double what it is now.”

I round out the video with takes from old pros lead NASA scientist Jim Hansen and Admiral David Titley, the US Navy’s Chief Oceanographer: 

Read more

Ohio State News Release

The 2010 Uplift Anomaly (green arrows), superimposed on a map showing the 2010 Melting Day Anomaly (shaded in red). Click to Enlarge.

An unusually hot melting season in 2010 accelerated ice loss in southern Greenland by 100 billion tons – and large portions of the island’s bedrock rose an additional quarter of an inch in response.

That’s the finding from a network of nearly 50 GPS stations planted along the Greenland coast to measure the bedrock’s natural response to the ever-diminishing weight of ice above it.

Every year as the Greenland Ice Sheet melts, the rocky coast rises, explained Michael Bevis, Ohio Eminent Scholar in Geodynamics and professor in the School of Earth Sciences at Ohio State University.  Some GPS stations around Greenland routinely detect uplift of 15 mm (0.59 inches) or more, year after year. But a temperature spike in 2010 lifted the bedrock a detectably higher amount over a short five-month period – as high as 20 mm (0.79 inches) in some locations.

In a presentation Friday at the American Geophysical Union meeting in San Francisco, Bevis described the study’s implications for climate change.

“Pulses of extra melting and uplift imply that we’ll experience pulses of extra sea level rise,” he said. “The process is not really a steady process.”

Because the solid earth is elastic, Bevis and his team can use the natural flexure of the Greenland bedrock to measure the weight of the ice sheet, just like the compression of a spring in a bathroom scale measures the weight of the person standing on it.

Read more

Projected sea level rise IF we don’t get off our current emissions path (which is between A2 and A1FI).  The WashPost omitted any mention of climate change in its sea level rise story, even though a key source talked about it with the reporter.

by Elliott Negin, Union of Concerned Scientists, in a HuffPost repost. [I add some comments of my own at the end -- JR.]

The Washington Post flunked Climate Science Reporting 101 this week, fumbling an opportunity to remind its readers about the threat global warming poses right here, right now.

On Monday, the day the latest round of annual U.N. climate negotiations opened in Durban, South Africa, the paper ran a scene-setter in its front section headlined “Global pact gives way to local action.” It pointed out that countries, states, provinces and municipalities are initiating their own policies to cut carbon emissions in the absence of a universal binding agreement. That story was not the problem.

The second story, which was plastered on the paper’s front page, is where the Post fell down on the job.

“In Chincoteague, a stampede against beach changes” reported on a dispute between the federal government and town leaders in a small Virginia coastal resort town best known for its wild ponies. The town’s 4,300 year-round residents survive on tourism — some 14,000 vacationers visit daily every summer, according to the state transportation department. But its beach — a part of the Assateague Island National Seashore and the Chincoteague National Wildlife Refuge — is threatened by sea-level rise.

Without getting bogged down in the details, suffice it to say that the U.S. Fish and Wildlife Service, the federal agency that manages national refuges, recently proposed a new, 15-year plan to safeguard the more than 300 species of birds and other wildlife at Chincoteague. One of the options would move the public beach about a mile north where it would be less vulnerable to sea-level rise, build remote parking lots in a more stable area, and shuttle beachgoers in buses. The town mayor and many residents oppose the plan, fearing the proposed changes would turn off tourists.

The Post story included the what, who, where and how of basic journalism. What was missing was the why. Why is sea level rising and eroding the beach in Chincoteague?

Read more

Greenland Ice Sheet Ties Record for Mass Loss in 2011

Another day, another amplifying feedback or vicious cycle.

The Greenland ice sheet can experience extreme melting even when temperatures don’t hit record highs, according to a new analysis by Dr. Marco Tedesco, assistant professor in the Department of Earth and Atmospheric Sciences at The City College of New York.  His findings suggest that glaciers could undergo a self-amplifying cycle of melting and warming that would be difficult to halt.

“We are finding that even if you don’t have record-breaking highs, as long as warm temperatures persist you can get record-breaking melting because of positive feedback mechanisms,” said Professor Tedesco, who directs CCNY’s Cryospheric Processes Laboratory….

… melting in 2011 was the third most extensive since 1979, lagging behind only 2010 and 2007. The “mass balance”, or amount of snow gained minus the snow and ice that melted away, ended up tying last year’s record values.

The photo on the right is “Marco Tedesco standing on the edge of one of four moulins (drainage holes) he and his team found at the bottom of a supraglacial lake during the expedition to Greenland in the summer, 2011.”

It’s not news that there are amplifying feedbacks at work on the great ice sheets.  Just this March, the U.S. Jet Propulsion Laboratory published its analysis that Polar ice sheet mass loss is speeding up, on pace for 1 foot sea level rise by 2050.  That study found:

The Greenland and Antarctic ice sheets are losing mass at an accelerating pace, according to a new NASA-funded satellite study. The findings of the study — the longest to date of changes in polar ice sheet mass — suggest these ice sheets are overtaking ice loss from Earth’s mountain glaciers and ice caps to become the dominant contributor to global sea level rise, much sooner than model forecasts have predicted.

But the new CCNY study, based on in situ observations “during a four-week expedition to the Jakobshavn Isbræ glacier in western Greenland,” lays out for the first time a very specific amplifying feedback occurring way up north:

CLICK HERE TO READ MORE OR COMMENT

Read more