On The Radio – Pace of sea level rise tripled since 1990


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A new study found that sea levels are rising nearly three times faster than in previous centuries. (Chris Dodd/flickr)
Jenna Ladd| June 12, 2017

This week’s On The Radio segment discusses a recent study that found sea levels are rising at a significantly faster rate than in the past. 

Transcript: Scientists, in a new study, have found that the Earth’s oceans are rising nearly three times as quickly as they were throughout most of the 20th century.

This is the Iowa Environmental Focus.

This new finding is one of the strongest indications yet that a much-feared trend of not just sea level rise, but its acceleration, is now underway.

Their paper, published in May’s Proceedings of the National Academy of Sciences, isn’t the first to find that the rate of rising seas is itself increasing — but it finds a bigger rate of increase than in past studies.

The new paper concludes that before 1990, oceans were rising at about almost a half an inch per decade. From 1993 through 2012, though, it finds they rose by almost one and a quarter inches per decade.

To learn more about the study, visit iowaenvironmentalfocus.org.

From the UI Center for Global and Regional Environmental Research, I’m Betsy Stone.

Iowa State researchers receive grants to improve glacier flow models and sea level predictions


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                         Calving of the Aialik Glacier in Kenai Fjords National Park in Alaska. (Alaska National Park Service)
Jake Slobe | February 15, 2017

Iowa State University’s Neal Iverson and a team of researchers are working on research that will predict how much glaciers will contribute to the rise of sea levels.

The research will focus on the extent to which glacier-flow to oceans is likely speed up over the next century as the climate warms.

Iverson, an Iowa State University professor of geological and atmospheric sciences who has studied glaciers in Iceland and Norway, and the rest of the research team will look to lab experiments and field work to build more realistic computer models of glacier flow.

Iverson said about the project:

“Glaciologists are trying to predict how fast glaciers will flow to the oceans. To do that, we need new lab and field data to include complexity in models that is usually neglected. These are complicated systems. Modeling them is hard. But we need to include how water in ice affects its flow resistance, and we need sliding laws that are based on the real topography of glacier beds and that include rock friction. Adding these things really matters.”

Two new grants will help Iverson and his team fund their research, both of which grants are from the National Science Foundation.  The research will also receive funding from the United Kingdom’s Natural Environment Research Council to support the work of applied mathematicians at the University of Oxford in England.

Iverson is the lead investigator on both grant proposals. The other researchers are Lucas Zoet, an assistant professor at the University of Wisconsin-Madison and a former postdoctoral research associate at Iowa State; Ian Hewitt, an associate professor and university lecturer at Oxford’s Mathematical Institute; and Richard Katz, a professor of geodynamics at Oxford.

The first project will look at temperate ice, or ice at its melting point, and how this soft, watery ice resists deformation. That’s important because the resistance to deformation of temperate ice at the edges of ice streams – areas of rapid ice flow within the Antarctic ice sheet that can be hundreds of miles long and tens of miles wide – holds back the flowing ice.

The second project will support development of better “sliding laws” to help predict the sliding speeds of glaciers and ice sheets. Sliding laws are the mathematical relationships between the glacier sliding speed and the factors that control it, such as the stresses below the glacier, the water pressure there, the topography of the glacier bed and the concentration of debris in glacier ice.

Both projects will use the glacier sliding simulator Iverson has been using since 2009 to study glacier movement.

The new projects will add complexity to Iverson’s lab experiments. Debris, for example, will be added to the ice ring to study friction between it and the rock bed during sliding. In other experiments, temperate ice will be sheared between rotating plates to study how its resistance to flow depends on its water content.

NPR: “Ready — Or Not. Abrupt Climate Changes Worry Scientists Most”


Photo by Rob Baxter; Flickr

 

An expert panel at the National Academy of Sciences is calling for an early warning system to alert us to abrupt and potentially catastrophic events triggered by climate change.

The committee says science can anticipate some major changes to the Earth that could affect everything from agriculture to sea level. But we aren’t doing enough to look for those changes and anticipate their impacts.

To read more and to listen to the audio, head over to NPR.