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).