CAPE (Circum-Arctic PaleoEnvironments), was established as an
organization within IGBP-PAGES following a planning meeting held
in Copenhagen in September, 1995. CAPE has as its central mandate
to link international and national Arctic paleo-programs, and
to provide a forum for regional syntheses and modeling. The primary
emphasis of CAPE is to facilitate scientific integration of paleoenvironmental
research on terrestrial environments and adjacent continental
margins covering the last 250,000 years of Earth history, particularly
those tasks that cannot be easily achieved by individual investigators
or even regionally-focused research teams. The primary mechanism
by which CAPE will perform its role is through a series of tightly
focused workshops that address specific topics identified by the
community as key to our understanding of the role of the Arctic
in the climate system.
The first task identified for CAPE was to define the spatial and
temporal patterns of environmental change in the Arctic during
the Holocene, the last 10,000 years of Earth history. The Holocene
offers possibilities for paleoenvironmental reconstruction at
a level of precision unavailable for earlier periods. There exists
a rich and diverse set of proxy data in a continuous, or near-continuous
time series, that offers the potential for high spatial and temporal
resolution. The Holocene includes the interval of instrumental
and written records, thus allowing a firmly-based calibration
of proxy data in terms of climate variables, and it overlaps with
the period of rapidly increasing CO2 content in the atmosphere,
a significant feature to be evaluated when predicting future climate
change. A key element of CAPE is to ensure that the syntheses
are data-based, with full documentation of the sources, and archiving
of the primary data in one of the international paleoenvironmental
databases.
Planning
An organizational meeting for the CAPE Holocene Project was held
in London, UK, in September, 1996. The meeting was attended by
the CAPE Steering Committee and local Organizing Committee, who
together established the primary objectives for the project. To
synthesize the vast array of observational data, twelve regions
were defined (Fig. 1).
For each region, two individuals were identified and recruited,
one each for the marine and terrestrial realms (Table 1). These
individuals were to coordinate the regional compilations and to
insure that the data were transcribed on to standardized forms.
As dataforms were completed they were entered on to digital spreadsheets
so that the regional syntheses could be compiled for the entire
Arctic and compared to model simulations in real time during the
meeting.
Strategy
A wide range of terrestrial and marine proxies exist as continuous
times series for the Holocene. Our goal was to first characterize
the Earth's surface at 1 ka time slices throughout this period.
On land, reconstructions were based primarily on paleovegetation
data (pollen and macrofossils) interpreted in terms of a limited
number of vegetation types. Additional surface characteristics
include the distribution of lakes and glacier ice, and paleoshorelines.
Paleoenvironmental data are also available from ice cores, and
diagnostic changes in isotope data in organic matter from lakes,
aerial plankton, diatoms, and various other faunal and floral
elements. Key marine characteristics are the seasonal and permanent
sea ice distribution, sea surface temperature (SST), water mass
type (e.g. Polar versus Atlantic/Pacific) and dominant currents.