Climate Change Today

1. Is it Really Changing?

2. If so, are Humans the Cause?

Temperature Change in the Last 1000 Years

Temperature Change Since 1850

World Temperature Anomaly for 2009Temperature increase is not evenly distributed.

Minimum Arctic Sea Ice Sept. 1979

Minimum Arctic Sea Ice Sept. 2005

CERES UC Boulder

What Did Our Snowy/Cold Winter in the Eastern U. S. Mean?

Is carbon dioxide an effective greenhouse gas?

http://www.youtube.com/watch?v=kGaV3PiobYk&feature=related

The Keeling Curve and rising CO2 today

Where is the carbon dioxide coming from?

• Atmospheric CO2 has ranged between 180 parts per million (ppm) and 300 ppm over the past 800,000 years.

• Today, CO2 levels are around 390 ppm.

HUMAN-INDUCED INCREASES IN ATMOSPHERIC CARBON DIOXIDE AND METHANE

Carbon dioxide1. Burning of fossil fuels – oil, coal, and natural

gas2. Clearing rainforests and burning the wood

MethaneMethane is produced by anaerobic decomposition of

organic material.1. Burning fossil fuels2. Rice paddies3. Cattle raising

• http://climate.jpl.nasa.gov/ClimateTimeMachine/climateTimeMachine.cfm

The Vostok Ice Core and how temperature, carbon dioxide, and methane work together.

• As an ice age ends, temperature starts to rise before either carbon dioxide or methane. Cause: Milankovitch cycles.

• As ocean temperatures rises, its ability to absorb CO2 decreases. Then, CO2 begins to increase in the atmosphere.

• Methane hydrate in ocean floor sediments begins to melt, releasing CH4 into the ocean and then into the atmosphere.

• As more CO2 and CH4 are released into to the atmosphere, temperatures are driven upward in a positive feedback loop.

Is there agreement among climate scientists about global warming and its cause?

97% of climate scientists in a University of Illinois study agreed that…

1. Climate is warming, and 2. Human activities are a significant factor in that warming.

http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf