Lessons and Legacies of International Polar Year 2007-2008 (2012) / Chapter Skim
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3 Scientific Advances and Discoveries
3 Scientific Advances and Discoveries
Pages 27-66
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From page 27... ...
AND SUBGLACIAL SYSTEMS Now it is driven by the desire to learn about different kinds of unknowns, such as the consequences of chang- During IPY, numerous international teams ing climate, ecosystems that exist on the underside of addressed scientific issues from on, within, and below the ice, changing patterns of sea ice, and mechanisms the world's two massive ice sheets, in Greenland and of ice sheet flow. International Polar Year 2007-2008 Antarctica (Figure 3.1)
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From page 28... ...
variations, which in this case are created by regional Taken together, these assessments showed that the pace mass redistributions within the ice sheets. IPY findof ice sheet mass loss has been increasing since the end ings from the LEGOS1 project using GRACE data of the last century, accelerating sea level rise.
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From page 29... ...
Thick black lines along the coast are interferometrically derived ice sheet grounding lines. Bottom: Satellite-based passive microwave images of the sea ice cover have provided a reliable tool for continuously monitoring changes in the extent of the Arctic ice cover since 1979.
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From page 30... ...
Observa- potential awakening of the East Antarctic ice sheet, a tions of accelerating ice flow following the collapse of potentially powerful influence on global sea levels and Antarctic ice shelves confirmed the buttressing effect of the climate system. Surface mass balance in East Antice shelves on ice flow and underscored the importance arctica is a fundamental but poorly known component of ice shelves to ice sheet stability (Rignot et al., 2004; of the ice sheet mass balance (IPCC, 2007a)
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From page 31... ...
The Antarctic Gamburtsev Province project used cutting-edge airborne radar to investigate the Gamburtsev Mountains which are completely covered by ice near the center of the East Antarctic Ice Sheet. The data reveal an Alps-like mountain range incised by fluvial river valleys in the south and truncated by the landward extension of the Lambert Rift to the north (Figure 3.5)
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From page 32... ...
. The negative mass balance of the glacier persists Extensive research was conducted during IPY to today,3 including accelerated thinning of ice volume understand the multifaceted role of sea ice -- that is, and retreat of the ice margin, indicating that climate ocean (salt)
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From page 33... ...
Cutting-edge airborne radar was used to investigate the Gamburtsev Mountains which are completely covered by ice near the center of the East Antarctic Ice Sheet. Bottom: (A)
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From page 34... ...
Instrumental time series of minimum ice extent leading up to 2006 showed that there had been an ~8 percent areal loss per decade in Arctic sea ice, with the strongest losses occurring in areas such as the Kara and Barents Seas. Thus IPY provided an opportunity to study the changing Arctic in a time of rapid change.
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From page 35... ...
indicated that the that 2007 represented a tipping point leading to an FIGURE 3.8 Satellite tracking pro vides information on Arctic sea i ce age, which correlates with thickness. Upper panels show the s patial pattern of sea ice age at the end of February in 2009 ( upper right)
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From page 36... ...
One contributing factor to recently been explored between Antarctic sea ice extent these changes may be the decrease in both the extent changes and variations in the state of the Southern and thickness of the Arctic sea ice cover (Serreze Annual Mode and the El Nino–Southern Oscillation et al., 2007)
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From page 37... ...
are providing data critical for While disappearing sea ice in the Arctic, por- determining the pace of future change and identifying tions of Antarctic, and glaciers are among the most the complex mechanisms driving ecosystem modificavisible surface indications that our planet is warming, tions in both the Arctic (western Arctic, e.g., Chukchi IPY research also served to highlight the vulnerabil- Sea) and the Antarctic (western Antarctic peninsula)
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From page 38... ...
Here recent studies been warming and changing salinity, especially from support the idea that the sensible heat carried by this the Laptev Sea into the Canada Basin (Dmitrenko et water causes the southward moving ice to melt, resultal., 2009, 2008; Polyakov et al., 2007) consistent with ing in a decrease in the salinity and density of the upper earlier observations first documented by the Surface part of the water column and thereby contributing to FIGURE 3.10 Cold, relatively fresh water from the Pacific Ocean enters the Arctic Ocean through the Bering Strait (blue arrows)
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From page 39... ...
biological distributions in many regions of W hile the Beaufort and Chukchi Seas north of the the Southern Ocean, particularly the western AntarcBering Strait largely support important fisheries for tic Peninsula region, are structured by hydrography, subsistence hunters in coastal communities, the ongo- circulation, and sea ice; (2) Antarctic krill use a range ing transformation of these marine ecosystems suggests of overwintering strategies; (3)
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From page 40... ...
Circulation modeling studies of Circum- showed the importance of the circulation in determinpolar Deep Water intrusions onto seas west of the Ant- ing shelf residence times of water and biota, transport arctic Peninsula and in the Ross Sea showed differences pathways, and retention regions, which have implicain vertical mixing of this water mass that have implica- tions for connectivity and recruitment of Antarctic tions for different basal melting rates of ice shelves and krill populations (Piñones et al., 2011; Wiebe et al., nutrient supply in the two regions (Dinniman et al., 2011)
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From page 41... ...
These rates are critical to providing estimates of the potential for sea level rise caused by melting of the 6 http://www.antarctica.ac.uk/staff-profiles/webspace/dutrieux/ West Antarctic ice sheet (Rignot et al., 2011)
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From page 42... ...
Recent studies suggest that this enhanced uptake will MARINE CARBON CYCLING AND be short-lived with surface waters rapidly warming OCEAN ACIDIFICATION and equilibrating with the atmosphere. Furthermore, release of large stores of carbon from the surrounding The Arctic marine carbon cycle and exchange of Arctic landmasses through rivers into the Arctic Ocean carbon dioxide (CO2)
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From page 43... ...
. Although the chemistry The intimate connection of the polar regions with of this effect is well understood and not much debated, the rest of the globe is most evident in the atmosphere, the full consequences of ocean acidification for marine where air from lower latitudes can be transported to the ecosystems and human well-being are only beginning poles in a matter of days.
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From page 44... ...
Projects focused on IPY provided. observations of the polar atmosphere, such as IASOA Arctic haze has been known to have much of its (International Arctic Systems for Observing the Atmo- origins from Northern Hemisphere anthropogenic sphere)
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From page 45... ...
Current studies do not provide a bromide. Activation of the trace amounts of bromide ready explanation for the observed expansion of sea ice in the snow on top of the Greenland ice sheet is able extent in the eastern portions of the Southern Ocean to support vigorous bromine chemistry that was shown (Thompson et al., 2011)
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From page 46... ...
For example, in the polar regions of the geospace environment. The modulation of the the solar wind energy is transferred into disturbances magnetosphere's open-closed boundary (OCB)
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From page 47... ...
Although the authors could not conclusively show that the polar surface air temperature patterns are TERRESTRIAL EARTH SYSTEMS physically linked by geomagnetic activity, they did dem- AND PERMAFROST onstrate that geomagnetic activity likely plays a role in modulating wintertime surface air temperatures. Current warming of the planet is contributing to Images of the aurora taken simultaneously in the changes in terrestrial environments that have large Northern and the Southern Hemispheres during IPY impacts on society.
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From page 48... ...
. The interplanetary magnetic field moves with the solar wind velocity.
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From page 49... ...
of the Arctic Ocean north of Europe. The mean warm Permafrost is soil and other subsurface materials ing of 1-2°C over the last six to eight decades has been that remain frozen year after year.
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From page 50... ...
. Evidence is results that exemplify large differences in the existence now emerging that deep-soil organic matter otherwise and state of permafrost between sites that vary from locked in permafrost in Alaska and northern Sweden is continental to marine and from sea level to mountains starting to be released (Dorrepaal et al., 2009; Schuur et (Christiansen et al., 2010; Romanovsky et al., 2010; al., 2009)
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From page 51... ...
A decline in freshwater storage across fish associated with arctic sea ice; guillemots now feed the central Arctic Ocean and recognition that circulation their nestlings lower quality and less abundant bottomthrough the Arctic Basin controls freshwater dynamics dwelling prey, resulting in lower breeding success and raises questions as to whether Arctic Ocean freshwater chick growth rates. Summer ice retreat has also shifted flows are intensifying.
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From page 52... ...
The precipitous minimum in Arctic summer sea al., 2010) ; and reduced safety of hunters traveling on ice extent in 2007 (Stroeve et al., 2007)
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From page 53... ...
The recovery of a new 100,000-year-long ice thermometry work10 confirms this independently. Analcore record from one of the most vulnerable portions of ysis of global sea surface temperature data and atmothe Antarctic continent is producing the first Southern spheric reanalysis data products has shown that the Hemisphere climate and greenhouse gas record with the same time resolution and duration as the ice core 10Anais Orsi and Jeffrey Severinghaus, Scripps Institution of records from the Greenland ice sheet.
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From page 54... ...
Studying the amount of melt that occurred on the Greenland ice sheet during this period can help advance modeling efforts and enable scientists to understand future climate warming caused by anthropogenic increases in CO2. This map shows the NGRIP (North Greenland Ice Core Project)
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From page 55... ...
In contrast to the dramatic shifts between is that it demonstrated, for the first time, instability glacial-interglacial end member climate states evident in the West Antarctic ice sheet, revealing Antarctica's in Pliocene-Pleistocene and Oligocene drill cores on the vulnerability to oceanographic warming and changes same coastal margin, the early Miocene paleoclimatic in atmospheric CO2, with dramatic consequences fluctuations were subtler under warmer, more equable for future changes in global sea level. This important
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From page 56... ...
, is an extraordinary surprise because lake located 100 km north of the Arctic Circle in north- it suggests repeated intervals in the past when the eastern Russia (see also "Paleoclimate Tools" section Greenland ice sheet may have been much smaller than in Chapter 4)
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From page 57... ...
. At the same time, changes in the size of the 31 is especially interesting because this interval coin- Greenland ice sheet over its history have been primarcides by half a precession cycle with the last time ily controlled by temperature, with warming in the ANDRILL chronicles the collapse of the WAIS and past always causing considerable ice sheet shrinkage the Ross Ice Shelf (Naish et al., 2009)
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From page 58... ...
(G) Northern Hemisphere average proxy temperature anomalies (10year means)
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From page 59... ...
Changes in sea ice and the extent engagement of polar residents, particularly Arctic of ice sheets create feedbacks in the climate system with indigenous people, in IPY operations. Such broadening implications for regional change and sea level fluctua- of the research base and scope led to significant science tions around the world.
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From page 60... ...
, academic research and local/indigenous knowltive models, and groundbreaking research paradigms. edge, are needed for a comprehensive understanding of There have been many pioneer advances in the the polar regions and processes.
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From page 61... ...
. By adding a sociocultural perspective and indigenous knowledge, ice scientists broadened the IPY agenda indicators to evaluate the status of sociocultural well in sea ice research beyond its habitual focus on ice dynamics being of Arctic population at the community, local, and and coupled ocean-atmosphere-ice modeling (Druckenmiller et regional levels (Crate et al., 2010)
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From page 62... ...
; it illustrated remarkable parallels evant to local residents. It argues for collaboration with in human advances into both northern and southern the new groups of stakeholders on research planning polar regions.
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From page 63... ...
.15 health dimensions as a recognized thematic area of study. Overall, new research in the social science and IPY activities related to human health were primarily humanities fields helped advance a broad variety of focused on the permanent inhabitants of polar regions, themes: the well-being of polar communities; use of with additional efforts to reach transient and nomadic natural resources and economic development, particu communities as well.
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From page 64... ...
, several IPY health research focused on a suite of issues of IPY studies were chartered to address these issues. "The concern to Arctic residents, including health impacts Inuit Health in Transition" was a large international of environmental contaminants, climate change, rap- study focused on diet and lifestyle factors (smoking, idly changing social and economic parameters within physical activity, etc.)
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From page 65... ...
. During IPY, Circumpolar regions experience unique chal there were a number of research projects that explored lenges in the delivery of health services because of behavioral and mental health issues and the relation- the dispersed populations and geographic isolation.
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From page 66... ...
Lake sediment sequences, ice cores, and tree els have overestimated accumulation due to snowfall. ring records from the circumarctic show that recent Cutting-edge radar measurements of the bottom of the warming has reversed the cooling trend of the last East Antarctic ice sheet yield insight on ice sheet origins.
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