Transcript Variations in greenhouse gas (nitrate) with short

Climate Change and Public Health
Maine’s Climate Future
(and past)
George L. Jacobson
Professor Emeritus of Biology, Ecology, and Climate Change
Maine State Climatologist
Climate Change Institute
The University of Maine
April 7, 2010
Climate Change Institute
(formerly Institute for Quaternary and Climate Studies)
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Climatology/Paleoclimatology
Historic climatology
Terrestrial paleoecology
Paleolimnology
Prehistoric archaeology
Glacial geology and glaciology
Atmospheric chemistry (incl. ice cores)
Geochemistry
Maine State Climatologist (GLJ)
“Maine Climate News” Web Site
Climate Change Institute
The University of Maine
Central question:
What is the natural variability of the earth’s climate, and
what are the underlying mechanisms?
Weather or climate?
El Nino tendency over time
(Nov. to Mar.)
All-time state record low temperature (– 50 F)
OFFICIAL RECORD
16 Jan 2009
20,000 years ago was the most recent glacial maximum
Maine under ice
Regular ice ages characterize the past million years
(information derived from ocean sediments)
Present interglacial (Holocene)
warm
cold
C.D. Keeling – IGY 1957
390 ppm as of February 2010
Projections show Maine becoming warmer
and wetter in all regions of the state.
Was this winter a taste of late-21st Century norms in Maine?
Maine’s climate is highly compressed: equal to that of northern Europe
Maine’s steep climate gradient produces
interesting patterns of range limits in plants.
Plant-hardiness zones have been shifting northward
Lakes have become ice-free earlier in the year
Range of deer ticks is spreading northward in recent years.
Future change are just the opposite of what happened in the past
1000 years --- southward expansion of spruce during a cool period.
Sea-level rise is likely to accelerate
Courtesy UM Prof. Gordon Hamilton
Implications for Maine of global instabilities caused by
climate change (broadly defined):
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Potential demand for resources (water, food, space, etc.)
Economic disruptions of many kinds
National security instabilities
Cumulative demand for health-related services & resources
Many others…
Discussion?
Records of atmospheric N2O and of Dansgaard–Oeschger events over a 16,000year interval during the last ice age.
Schmittner & Galbraith (2008) Nature 456:373-376.