MTNCLIM 2005
FROM A PALEO PERSPECTIVE
G.M. MacDonald
UCLA
This is the Powerpoint presentation of a summary talk for
the 2005 MTNCLIM Meeting. The presentation was to
have provided a synthesis of the meeting from a
viewpoint that integrated both modern and paleo studies.
The presentation is dedicated to the memory of Dennis
Machida.
This is an educational presentation only and all images are copyrighted and not to be reproduced
Three themes regarding progress on mountain climates
are explored -
Coherence
Uncertainty
Ways Forward
COHERENCE – Long climatic records display variability
that is greater in magnitude and duration than that
anticipatable from instrumental records.
These records are now being assimilated and used by
the larger community. This shows coherence in the paleo
record and also in the concerns of paleoclimatologists and
modern climatologists, ecologists and resource managers.
The occurrence of a large
Medieval mega-drought that
impacted almost all of western North
America and is without precedent in
the historical period is a coherent
signal seen in many types of paleo
records. It provides evidence of
extreme the range of natural
variability can be.
, C.M. Eakin, D.M. Meko and
E.R. Cook, C.A. Woodhouse
D.W. Stahle, 2004:
Long-term Aridity Changes in the Western United
States. Science, Vol. 306
The mega-drought impact extended from mountains in Canada to California and provides an ‘extreme
scenario’ for resource management
Case and MacDonald 2003
Eric Kuhn’s talk displayed how resource managers have integrated paleo data from another widespread
drought that occurred in the 16th century
Stahle et al. EOS
COHERENCE – Paleoclimatologists are developing longer
high resolution multi-proxy climate records that span the
entire Holocene and are similarly being incorporated into
the work of climatologists, ecologists and resource
managers working with contemporary questions.
The work of Jeffery Stone
and Mark Shapely
presented at MTNCLIM
demonstrate the high
resolution and sensitivity
of Holocene paleo
records from lakes.
Quercus turbinella
Aber et al 2001 Bioscience
Ron Nielson’s talk demonstrated how mid-Holocene
distributions of tree species can be incorporated to help
understand potential future global scenarios.
COHERENCE – Long term climatic records are now
accumulating in spatial networks and show consistent
patterns of regional and temporal variability. These
insights help inform us of spatial patterns in climate
variability that are likely to occur today and in the future
The talk by Stephen Gray provided
examples of regional patterns of
past environmental change that are
important in understanding current
conditions in the western mountain
region
Gray et al GRL 2003
COHERENCE – Instrumental and paleo climatic records are
showing evidence of the same potential ocean-atmosphere
drivers.
Reconstructions of the PDO provide a coherent picture of this phenomena and also indicate
that it is prone to variability in its frequency and intensity
MacDonald and Case
In press GRL
Megadrought
Materials presented by Emma
Watson and Greg Pederson
illustrated how modern climate
patterns can be integrated with
glaciological and tree-ring
research
Pederson, Fagre, Gray, Graumlich, 2004 GRL
UNCERTAINTIES – We still do not often fully
understand (or adequately appreciate the complexity
of) the linkages between climate and ecologicalevolutionary responses in the modern and paleo data
sets.
Information presented in talks or posters by the researchers listed below are just some of the
examples of work that highlighted the complex nature of the relationship between climate and
ecosystems
Brandi Bracht
Malcolm Hughes
Tom Whitham
Craig Allen
UNCERTAINTY – We do not fully understand the often
non-linear dynamics between potential climatic drivers.
We do not understand the underlying forcing factors of
the ocean-atmosphere drivers of variability
Work by Stephen Gray highlights the complex linkages in the ocean-atmosphere system
Gray et al 2003 GRL
UNCERTAINTY – Despite all our progress in modern
climatology and paleoclimatology, in terms of bidecadal
to multidecadal to centennial droughts – the only thing
that is certain about the future is uncertainty.
Based on paleo records we cannot yet build models that predict or retrodict the occurrence of
prolonged severe droughts – despite the occurance of such droughts in our records and in the historical
period
Based on paleo records and inturmental climate records we cannot predict if the current drought in the
Colorado Basin will end next year or 1000 years from now
Based on paleo records and modern instrumental data no one predicted that the 2004-2005 winter
would have broken the 100-year precipitation record in southern California
Southern California Precipitation – 2004-2005
WAYS FORWARD –
1. Higher temporal and spatial resolution records to more closely link
both long and short term records with modern processes (lapse
rates for example – Jessica Lundquist) – in critical sites.
2. More integrated paleo and modern networks of uniform
observations aimed at specific substantive questions (many here)
3. Greater model development and model-data integration for testing
and hypothesis generation – both climatic and ecological (Hughes,
Mitch Plummer, Ron Nielson, Alex Hall etc.)
4. More molecular genetic work – genotypes are more ‘real’ than
species and we are not ‘seeing’ them (Whitham)
5. More international participants – Canada AND Mexico in particular
(but lets not forget Alaska…)
6. More graduate students in the fold – because they will think of
things we cannot imagine!
The future’s uncertain and the end
is always near
Jim Morrison (UCLA 1965)
This was the original ending slide for the presentation and made in reference to climate change and
western mountain systems.
I could not have guessed that these words would be so poignantly and sadly applicable beyond that
context.