Climate Feedback

Timeline: Ice memory

Some of scientists’ gravest concerns about future climate change are rooted in the past. Records studied by paleoclimatologists reveal that the more extreme possibilities for this century and beyond — temperatures soaring, ice sheets vanishing, fertile lands withering into deserts — were realized previously on Earth when atmospheric greenhouse gas levels surged. At this summer’s AGU Chapman Conference on Abrupt Climate Change, researchers described this turbulent history through all manner of proxies – ice, tree rings, corals, marine and lake sediments, among others. But few talks went without a slide showing the wiggly line of a deep ice core.

Each proxy has its own merits, but ice cores offer records of climatic history whose detail and completeness are unmatched. Their data stretch back 800,000 years and are conveniently located in some of the world’s most climatically sensitive regions. Two new features on Nature Reports Climate Change pay homage to the work of scientists who, over the last few decades, have been tireless in their efforts to extract clues about the Earth’s past climate from air bubbles, isotopes and dust particles trapped in ice.

First, a timeline of deep polar cores documents in fine detail the discoveries of scientific pioneers, from the first efforts to read ice records through to today’s hunt for ice a million years old or more. Complementing this chronology of scientific discovery is an interactive map layer for Google Earth. This virtual tour takes you to the sites where polar researchers have holed up year after year, drilling thousands of metres of Greenland or Antarctic ice before hitting bedrock. In the window below, spin the globe to the pole of your choice, zoom in and click on the map points to see the drilling stations. For a full-size view and more navigation controls – plus a built-in web browser window where you can check out the timeline – download the map layer here and run it in Google Earth, which you can download here.

As I highlighted earlier on the blog, this month’s issue of NRCC also features an exclusive interview with world-renowned glaciologist Lonnie Thompson. On his quest to understand how ice is changing atop the world’s mountains, Thompson has spent more spent more time above 20,000 feet than any other human being; he’s currently with a team at the Quelccaya glacier in Peru, racing to bring back ice that is rapidly being lost to climate change. The American Museum of Natural History has put together a great video on his work.

Such endeavours come with scientific challenges as well as personal ones. As understanding abrupt climate change becomes increasingly crucial, ambitious plans for studying these icy environs will be ever more important.

Anna Barnett


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    Bishop Hill said:

    Apparently Dr Thompson does not make his data available to others. His work should be ignored.

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    John Nethery said:

    It is very very strange that the ice core data actually shows that temperature change precedes CO2 change by several hundred years and on average 800 years (see IPCC 2007 Report, Chapter 6 page 444). Are we seeing a new kind of force in nature that a forcing agent can affect preceding events

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