“Polar Ice Volumes Over Time: Is the Climate Debate Over?”
A Conversation with Wieslaw Maslowski, Research Professor of Oceanography, Naval Postgraduate School, Monterey; hosted by Larry Smarr, Director, California Institute for Telecommunications and Information Technology (Calit2), UC San Diego and Irvine
LS: Why are we looking at the Arctic as the canary in the coal mine?
WM: if you look at the earth as a whole, there will be a 1.5-2.5 degree temp increase. Polar regions will increase by an average of 3-5 degrees C or more, while tropical temp changes will be less. You don’t have to change the temperature by that much to see significance of melting in those regions, which increased radiation of shortwave atmosphere, which further increases melting.
A map shows that the Arctic is like avery large estauary with a lot of big rivers, which helps to maintain a fresh-water layer at the surface. That change is due to freshwater coming from Pacific side. Some ice is exported, so new ice is formed.
LS: NW passage is open in summer, but there are actually two different passages.
WM: Key aspect of climate change in arctic is the opening of shipping routes. When ice shrinks, shipping routes open that allow goods to be shipped from Asia to the US/ Canada in a shorter time. Still need icebreakers to pass through these routes. The prob is that the sea ice can be moved quickly by winds, and without ice breaker protection, you may lose the vessel or the cargo, such as oil and gas. We don’t have security for this cargo without ice breaker exports.
WM: Over about 23 years (1979-1002) , there’s about 17 percent change in ice area. IN ADDITION, WE MUST determine the change in thickness also, which has changed almost twice as fast as the area. Satellites provide only a part of the picture. Not seeing changes in depth, width, only 2D changes in ice expanse. Ice volume cycles continued steadily into the late 1990s, but then took a sharp dip. Some satellites ar now able to provide estimates of thickness. Ice volume has been declining at 1000 km cubed/year. Under 9000 km cubed of ice volume left, which means you can prove the decline of arctic ice.
However, some ice will remain, North of Greenland, that will survive beyond 2010, 2020. But most will be gone much sooner than we have believed before.
LS: Previous IPCC predictions had put that number at 2030-2050. What are the physical reasons for that? Why melting from below?
WM: Most recent estimates are suggesting the sometime around 2030-2040 there will be a week in summer where there’s no ice. Because IPCC models have not accounted fully fo melting from below due to warm water from Pacific side are underestimating the time it will take to reach ice-free summers. WArm water coming from Pacific side has a strong influence on the water even in the winter. In the summer, ice retreats, ocean absorbs the sunlight and more melting takes place. The winter will still have ice, but the summers will be ice-free. Yesterday’s ice concentration — Bering strait is already ice free, as are some of the Alaskan waters. Already below average of May 2007, including the last 4 years.
LS: one thing I like about this is that, looking globally, the Arctic is one of the first places we’ll notice this ice melting.