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International Polar Year 2007–2008 - WMO

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216<br />

IPY 20 07–20 08<br />

so-called Dansgaard-Oeschger events; very abrupt,<br />

millennial-scale, climatic shifts that occurred during<br />

the last glacial period. Understanding the cause of<br />

these events has implications for predicting future<br />

change. Nevertheless, none of the previous ice cores<br />

from Greenland provided an undisturbed climate<br />

record of the last interglacial, the Eemian, which<br />

occurred between about 115,000 and 130,000 years<br />

ago and was warmer in the Arctic than our present<br />

interglacial period. Obtaining a record of this period<br />

from Greenland was an important IPY target.<br />

About 50% (in number) of all world glaciers and ice<br />

caps are found in the Arctic and, although the surface<br />

area of the Greenland ice sheet is about four times the<br />

area of all other Arctic glaciers and ice caps, the smaller<br />

ice masses are generally at lower elevation and have<br />

warmer mean annual temperatures, and so are susceptible<br />

to greater percentage mass loss in response<br />

to warming. Globally, glaciers and ice caps, including<br />

those surrounding the Greenland and Antarctic ice<br />

sheets, store ~ 0.5 to 0.7 m of sea level equivalent, and<br />

are currently contributing at about the same rate to<br />

sea level rise as the combined contributions from the<br />

ice sheets in Greenland and Antarctica (IPCC, 2007).<br />

They will continue to contribute into the 21st century<br />

and beyond. Many of the Arctic glaciers and ice caps<br />

terminate in the oceans and 30-40% of their mass loss<br />

is from iceberg calving. Nevertheless, the uncertainty<br />

both in the surface mass balance and the calving fluxes<br />

of the Arctic glaciers is still large. Hence, IPY aimed to<br />

obtain baseline glaciological data on extent, dynamics<br />

and mass balance of the irregularly distributed Arctic<br />

ice masses in regions such as Alaska, the Canadian Arctic,<br />

Iceland, Svalbard, Franz Josef Land, Novaya Zemlya,<br />

Severnaya Zemlya and northern Scandinavia. The variations<br />

in space and time of the monitored ice bodies<br />

in polar and mountain regions could then be extrapolated<br />

to estimate regional contributions to sea level<br />

change and linked to the global hydrological cycle.<br />

Developing Greenland and Arctic<br />

Glacier IPY projects<br />

The ICSU-<strong>WMO</strong> call for “Expressions of Intent”<br />

(EoI) for IPY projects elicited approximately 30 EoIs<br />

between November 2004 and January 2005 which<br />

were focused on the terrestrial ice masses of the Arctic.<br />

These can be broadly categorized into five groups.<br />

• Characteristics and status of the Greenland ice<br />

sheet. This group included EoIs 74, 94, 581, 607, 883,<br />

933, 951 and 1120. 1 Two geoscience EoIs, 763 and<br />

784, were also linked to this group as they planned<br />

to share logistics to explore the geophysics of<br />

Greenland, including characteristics of the bedrock<br />

beneath the ice sheet.<br />

• Future response and stability of Greenland. This<br />

included EoIs 69, 136, 187, 245, 334, 381, 418 and 765.<br />

• The record of past environments from Greenland<br />

ice cores; EoIs 62, 203 and 561.<br />

• Satellite remote sensing of the Greenland ice sheet;<br />

EoI 910, which was bipolar and also included study<br />

of the Antarctic ice sheet.<br />

• Changes to Arctic glaciers and ice caps; EoIs 30, 233,<br />

654, 684, 756 and 1007.<br />

Over the next several months the proponents of<br />

these EoIs, encouraged by the IPY Joint Committee<br />

and the <strong>International</strong> Programme Office, worked to<br />

combine their ideas and resources into larger full IPY<br />

proposals. Ultimately, seven full proposals that dealt<br />

with the Arctic ice sheets and glaciers were endorsed<br />

by the IPY Joint Committee (JC) in 2005–2006 (Allison<br />

et al., 2007; Chapter 1.5).<br />

Two of these (no. 91 and no. 125 - see below) were<br />

satellite remote sensing projects that also included<br />

investigation of the Antarctic, and two were “umbrella”<br />

projects submitted on behalf of international<br />

organizations. These latter projects, which generally<br />

did not propose specific research activities but sought<br />

to synthesize the results of other relevant projects in<br />

the Arctic and Antarctic, were no. 105 (State and Fate of<br />

the <strong>Polar</strong> Cryosphere) linked to the WCRP Climate and<br />

Cryosphere (CliC) Project, and no. 117 (<strong>International</strong><br />

Partnerships in Ice Core Science - <strong>International</strong> <strong>Polar</strong><br />

<strong>Year</strong> Initiative) linked to the <strong>International</strong> Partnerships<br />

in Ice Core Science.<br />

IPY projects on the Greenland ice sheet<br />

IPY project no. 118 (The Greenland Ice Sheet –<br />

Stability, History and Evolution), led by scientists from<br />

Denmark and U.S.A., was a very large and multi-faceted<br />

study that linked palaeoclimate, observational and<br />

modelling components to investigate past and future<br />

stability of the Greenland Ice Sheet, ice dynamics,<br />

sea level change and change in fresh water supply

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