Geoscience Reference
In-Depth Information
and from ships. These data show considerable variability of timescales of weeks,
years and decades. Further developments are essential both to the models and data
collection, with measurements in areas of ice shelves and in sea ice regions being
particularly challenging.
The interface between rock and the continental ice is very varied both spatially
and temporally
the ice can be frozen to the bed or be covered with till and water
that makes the sliding resistance of ice orders of magnitude lower. Some remote
sensing techniques have been developed, but validation of the technique is required
through direct observations. This will require signi
-
cant drilling of ice and with
much greater spatial mapping of the ice
rock interface to allow better calculations
of the rates of loss of ice from Antarctica and more accurate estimates of sea-
level rise.
Presently the Earth experiences Milankovitch cycles of about 100 000 years
which are related to the eccentricity of its orbit but prior to about 1.2million years
ago the period was 40 000 years, attributed to the obliquity of the Earth
-
s orbit.
The change has been observed in ocean sediments, but if old ice could be found
in Antarctica it would provide carbon dioxide and other important chemical signals
to help explain why the dominant period changed. Understanding the natural
rhythms is critically important to allow the anthropogenic impacts to be accurately
quanti
'
ed.
Many of the outstanding issues are so large that they are beyond the scope of
a single nation to provide, and hence international cooperation, already a very
strong characteristic of those operating in Antarctica, will need to increase further.
To address some of the issues associated with the Southern Ocean requires
continuous circum-polar measurements of a wide range of physical and biological
parameters. A plan has been developed entitled the Southern Ocean Observing
System to address the problem but it requires considerable investment from
many nations to achieve signi
cant progress. As many parts of the world experience
severe
financial budget constraints, it will be even more important to coordinate and
share the use of major assets in Antarctica, stations, ships and planes. These
activities will require some relaxation of national agendas and a more cooperative
approach.
The Antarctic Treaty System has proved to be very successful to date, but in
the longer term it will come under increasing pressure as the natural resources
on the other continents diminish. Although oil and gas are often discussed in an
Antarctic context, the extraction of rare Earth minerals might be the
first serious
challenge to the Treaty although identi
cation of their locations and their
mining will prove extremely dif
cult. The mineral resource issues are decades
away but they clearly need to begin to be addressed now before any crisis
might arise.
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