Post on 02-Jan-2016
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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
• 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, accelerating 2006-07)
Sea-level rise
CO2 Concentration
Av Surface Temp
Sea Level Rise (cm)
Dashed lines = 1990s projections
Rahmstorf, Church, et al., Science 2007
Solid lines = observed
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
Globally averaged, the earth is ~0.75 C warmer than it was in 1860
What are the Consequences?Increased temperature and incidence of heat waves
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 itemDocumented drop in female weight
1980 = 650lbs2004 = 507
Minimum weight needed to become pregnantUnprecedented numbers swimming and then found drowned.
Global Warming
Global WarmingGlobal coupled atmosphere-ocean-ice model
Hoegh-Guildberg (1999)
Edith's Checkerspot Butterfly has been disappearing from the lower elevations and southern limits of its range.
What are the Consequences?Shifts in species ranges
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).