What is the Greenhouse Effect?
Increases in greenhouse gases will lead to increases in
global temperature
Data from 2007 IPCC report
Climate Change: Faster
than expected in 1990s
CO2 Concentration
Solid lines =
observed
•
Dashed lines = 1990s
projections
Av Surface Temp
IPCC 4 (2007) was limited to
science published by early 2006
• Subsequent research shows
increasing rates of:
 Global GHG emissions
3.3% in 2000s, vs 1.3% in 1990s
 Temperature rise
especially in polar regions
 Ice melt (Arctic: 40% loss since 1980,
Sea Level Rise (cm)
accelerating 2006-07)
 Sea-level rise
Rahmstorf, Church, et al.,
Science 2007
1975
1985
1995
2005
IPCC Fourth Assessment Report (2007) was very conservative.
Recent studies indicate accelerating change.
What are the Consequences?
Melting of glaciers and polar ice
Since 1850, glaciers in the
European Alps have
disappeared from more than
30-40% of their former range
What are the Consequences?
Increased temperature and incidence of heat waves
Globally averaged, the earth is ~0.75 C warmer than it was in 1860
September 2008 sea ice = 4.67 (ice was thinner so volume was record low)
What are the Consequences?
Sea Level Rise
Sea Level Rise
Biological Impacts
• Extreme weather events cause rapid range contraction
due to physiological tolerances being surpassed.
- You can see this in genetics – increase in heat
tolerant genotypes seasonally, then decadally in
fruitflies
• Phenology changes
• Abundance and community reassembly processes
• Sea level rise - salinization
• Ecosystem processes – decomposition, primary
productivity, etc.
What are the Consequences?
Melting of glaciers and polar ice
Polar bears need sea ice – seals and other marine
mammals main food item
Documented drop in female weight
1980 = 650lbs
2004 = 507
Minimum weight needed to become pregnant
Unprecedented numbers swimming and then found
drowned.
Global Warming
Global Warming
Global coupled atmosphere-ocean-ice model
Hoegh-Guildberg (1999)
What are the Consequences?
Shifts in species ranges
Edith's Checkerspot
Butterfly has been
disappearing from the
lower elevations and
southern limits of its range.
Average shift = 35 miles north
What are the Consequences?
Shifts in biological activity
Toads, frogs, and newts spawning early.
Spawning was 9 to 10 days earlier over a
17-year period.
Marmots are emerging from hibernation on
average 23 days earlier than 20 years ago. This
coincides with an increase in average May
temperatures of about 1.8oF (1oC).