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CLIMATE CHANGE SCENARIOS FOR YUKON FLATS
NATIONAL WILDLIFE REFUGE, ALASKA
Anna Springsteen University of Alaska and The Wilderness Society
Wendy Loya The Wilderness Society
Climate Change in the Northern Latitudes
• Since 1950, temperatures have already risen 2.2ºC statewide and 3.9ºC in the Interior
• Changes in Precipitation suggest increases, although lack of monitoring makes it difficult to tell
• Need for closer examination of climate change in northern-latitudes
Global Circulation Models (GCMs)
Used in IPCC 4th Assessment (2007) to look at potential climate change under several emissions scenarios.
We chose 5 models to run under the “A1B” emissions scenario: • Greenhouse gas emissions are expected to rise at rates similar
to today but eventually decline due to the use of more renewables and more efficient technologies.
5 ModelsEcham5 Gfdl2.1 Miroc3.2MR HadCM3CGCM3.1- And a composite(average) of the 5 models.
Past 2040 2080
Glo
bal E
mis
sion
s (G
t C /
yr)
0
5
10
15
20
25
A1B
Yukon Flats National Wildlife Refuge
Climate Change Predictions for the Refuge:
• Past and Future trends for Temperature and Precipitation
• Length of the Growing Season
• Change in Potential Evapotranspiration (PET) to estimate wetter or drier conditions
Year
Tem
pera
ture
(C)
1980 2000 2020 2040 2060 2080 2100
-10
-50
5
Cccma
Echam5
Gfdl2.1
Hadley
MirocMR
Composite
Regression of Composite
1961-1990 Mean
+ 2.74 C + 4.94 C
y = -108.8+0.052(Year)
TemperatureAll 5 models predict temperature increases over time.
Temperature
Annual Temperature Change (ºF)
• Annual temperatures increase 9ºF by 2080, or about 1ºF per decade
• This is an increase from 22ºF to 31ºF on average
Temperature
Winter Temperature Change (ºF)
• Winter temperatures increase 12ºF by 2080
• This is an increase from -3ºF to 9ºF on average
Temperature
Growing Season Temperature Change (ºF)
• Growing season temperatures increase 6ºF by 2080
• This is an increase from 52ºF to 55 to 58ºF on average
Growing Season
1980 2000 2020 2040 2060 2080 2100
100
140
180
Mean Modelled Length of Frost-Free Season
YEAR
Leng
th (D
ays)
PRISM152 days
167 days 178 days
+2.6 days per decade
• Date of freeze-up occurs 1.3 days later per decade
• Date of break-up occurs 1.3 days earlier per decade
• Thus, the “growing season” lengthens by ~3 days per decade to increase in length by 26 days
Precipitation
Annual Precipitation (inches)
• Annual precipitation increases from 10 to 13 to 15 inches.
• An increase of 0.5 inches per decade
Precipitation
Winter Precipitation (inches)
• Winter precipitation increases 63% by 2080
• This is an increase from 40 to 60 inches of snowfall
Precipitation
Growing Season Precipitation (inches)
• Growing season precipitation increases by 33%
• This is an increase from 7 to 9 inches of rainfall
Potential Evapotranspiration (PET)• Despite increases in Precipitation, conditions will
become drier
• Due to warmer Temperatures and a longer growing season, the Refuge may become considerably drier
Time Period
1961-1990 2035-2044 2075-2084
Wat
er D
efic
it
-25
-20
-15
-10
10% Drier
25% Drier
Overview
…Interior Alaska is projected to warm more in the next 40 years than it did in the last 150
…and become drier by up to 25%.
• Warmer temperatures will be found in all seasons, along with an increase in precipitation.
• However, evaporation will increase water demand more than precipitation will fill it.
• In addition, because the growing season will lengthen by a month, the period over which water demand occurs will increase as well.
Implications: Permafrost
• Thinning of discontinuous permafrost due to annual temperatures above 32ºF by 2100
- Shrinking of wetlands
- Unpredictable landscape changes
Implications: Forests
Hotter, drier growing seasons:
• More forest fires
• Switch to more deciduous vegetation
• Potential for more invasive plant and insect outbreaks
Implications: Wetlands & Rivers
• Unpredictable freezing and ice break-up
• Earlier pulse of spring runoff, less or more runoff?
• Possible lower river levels and drying wetlands
• Warmer water temperatures affecting river and lake food webs
Implications: Wildlife
• Increased habitat for certain species, decreased quality habitat for others
• Extended breeding and rearing seasons
• How will weather variability change with climate--more extreme weather events?
Conclusions
Climate models are not perfect and there are still many unknowns, but…
• Climate change is already visible in interior Alaska.
• The combined warming and drying of the future are likely to cause stress on vegetation, wildlife, and people
• Need to plan for the effects of climate change in a quantitative way
Contributors
Scenarios Network for Alaska Planning (SNAP)John WalshScott RuppBill ChapmanMark Olson
For More Information:
Summary Available at:
The Wilderness Society Websitewww.wilderness.org/library under "What's New"
orScenarios Network for Alaska Planning Website:
http://www.snap.uaf.edu/
Growing Season
1980 2000 2020 2040 2060 2080 2100
250
270
290
Mean Modelled First Date Below Freezing
YEAR
Dat
e (D
ays
sinc
e Ja
n. 1
)
+1.3 days per decade
PRISMSep. 26Day 269
Oct. 4Day 278sd=2.5
Oct. 9Day 283sd=1.5
1980 2000 2020 2040 2060 2080 2100
6080
120
Mean Modelled First Date Above Freezing
YEAR
Dat
e (D
ays
sinc
e Ja
n. 1
)
PRISMApr. 27Day 117
Apr. 20Day 111sd=4.2
Apr. 14Day 105sd=3.2
-1.3 days per decade
1980 2000 2020 2040 2060 2080 2100
100
140
180
Mean Modelled Length of Frost-Free Season
YEAR
Leng
th (D
ays)
PRISM152 days
167 days 178 days
+2.6 days per decade
Potential Evapotranspiration (PET)
PET(mm)
Precipitation-PET(mm)
PRISM 625 -4602040 700 -5002080 790 -565
Time Period
1961-1990 2035-2044 2075-2084
Wat
er D
efic
it
-25
-20
-15
-10
10% Drier
25% Drier
-625
-500
-375
-250
Year
Pre
cipi
tatio
n (m
m)
1980 2000 2020 2040 2060 2080 2100
1020
3040
5060 Cccma
Echam5
Gfdl2.1
Hadley
MirocMR
Composite
Regression of Composite
1961-1990 Mean
+ 6 mm/mo + 10 mm/mo
y = -183.6+0.104(Year)
Precipitation
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