Post-glacial climatic change and variability - The Global Climate System: Patterns, Processes, and Teleconnections - page 182

Table 6.1 (cont.)

Proxy method Definition Spatial extent Time scale Benefits Limitations

Pollen Pollen species from

undisturbed lake
and coastal cores

Mainly mid to high
latitudes where
trees and grass
grow

Normally a
few
millennia

Widespread use
Long records possible
Can indicate both
temperature and
moisture

Dating can be uncertain
Pollen identification can be
difficult
Depends on how vegetation
responds to climate

Speleothems Stalactites and

stalagmites in
cave
environments

Cave
environments:
depends on
water flow in
sedimentary rock

Normally a
few
millennia

Wide range of proxies
possible (chemistry,
trace elements)
Can indicate changes in
water cycle;
atmospheric
circulation

Limited locations
Dating can be uncertain
Difficult to interpret climate
variables

Varved sediments Sedimentation of
marine and lake
organic remains

Areas with high
sedimentation
rates and strong
seasonal
changes

Normally a
few
millennia

Annual and seasonal
resolution possible
O 18 analysis
Faunal assemblies

Best in closed-basin glacial lakes
Limited distribution

Historical records Written records,
diaries,
phenology, crop
harvests, etc.

Can be wide
ranging, but
usually mid to
high latitudes

Up to about
1500 years

Wealth of information
possible
Wide range of potential
sources
Can provide highly
detailed information

Patchy in space and time
Can be anecdotal and lack
accuracy
Requires cautious interpretation
Often emphasis on extremes
May not represent seasonal and/
or annual means

Greater details are available in Jones et al.( 1998 ); IPCC ( 2001 ); Jones and Mann ( 2004 ).