Welcome! Please get out objectives # for a stamp. Please read the board.

What do these have in common?

Climate and civilization Human civilizations change when climate changes 20,000 ybp (years before present) ice age: Bering strait freezes, people migrate to the Americas 8,000-7,000 ybp – warming period Mesopotamia flourishing, Jericho established

Mayan civilization – collapses suddenly 950 CE (common era – used to be called AD) Leif Erikson – 950 CE sails to Greenland

Black Death in Europe – famine – needed to import grain from China Little Ice age – Irish Potato Famine

Dust Bowl – 1930’s Mild but persistent La Nina conditions coupled with changes of sea surface temperatures + poor farming practices

Predicting future climate How do they do that anyway?

Global Circulation model

Global Climate Models: GCM’s Computer model divides atmosphere into chunks. Current conditions programmed into each chunk: temp, wind, [GHGs], etc Computer can generate current and future global temperature averages based on [GHGs]

Limitations of GCMs Complexity Feedback loops (not included in GCMs)  (+)Melting tundra permafrost and lower geologic formations– 500 billion tons CH 4  (+)Loss of albedo effect with ice  (-)Increasing albedo effect with clouds  (+) Increasing greenhouse effect with evaporating water Role of ocean and CO 2 absorption

Lesson from the Ozone Hole: 1930’s – CFCs invented 1970’s – mechanism of O3 destruction understood; models of possible effects suggest general thinning of O3 layer 1985 – Ozone hole documented as complete surprise – models were wrong – Montreal Protocol ratified

IPCC: Intergovernmental Panel on Climate Change UN group of 1,200+ scientists representing almost every country Jan 2007 –Absolute agreement on anthropogenic cause of current climate change. “Warming of the climate system is unequivocal” (100% confidence level) “There is very high confidence that the net effect of human activities since 1750 has been one of warming.” (90% confidence level)

How hot will it get? Depends on CO2 output: IPCC 2013 graphs

Predictions: If CO 2 goes to 450ppm by 2050, +2 o C (3.6 o F) CO 2 to 550ppm by 2050, +3 o C (5.4 o F) In 50 yrs, expect 4 o C warming (2012 World Bank Report) CO 2 of 350ppm is considered sustainable by climatologists Tipping point is probably at 2 o C (the point at which change due to human activity brings about sufficient new processes in nature to make any human reversal of the change impossible. )

Mauna Loa CO2 levels

Observations Europe – 2011/2012 – record winter snows and cold Texas – 2011 record 10,000 year drought? Australia 2013 – extreme heat – new colors on weather maps California – severe drought, wildfire seasons starting in January United States experienced 25 climate- and weather-related disasters that claimed 1,141 lives and each exceeded $1 billion ($175 billion total) in damages.

From the National Oceanographic and Atmospheric Administration (NOAA) The year 2012 was the 10 th warmest year since records began in was the 7 th warmest year. The 37 th consecutive year that the yearly global temperature was above average. Arctic ice melting at record rate Frost free season has increased by 21 days in CA, 9 days in TX, 10 days in CT Including 2013, all 12 years to date in the 21 st century (2001–2012) rank among the 14 warmest in the 133- year period of record. Only one year during the 20 th century—1998—was warmer than 2012.

Chasing Ice – ice core graphs, effects, glaciers

Big seven Change in precipitation patterns More severe weather events (droughts, floods, extreme hot/cold) Rising sea levels (glaciers melting) Changing seasons – earlier spring and shift of biomes away from equator Increased insect-borne disease Decreased availability of fresh water Acidification of ocean and bleaching of coral reefs (H 2 CO 3 )

Sea level rise Sea level rise.7 m by 2100 Melting glaciers add water volume to ocean (Greenland ice sheet stores enough water to raise seal level by 5-7 meters) Thermal expansion creates most of the increase

Where will the environmental refuges go? 50% of global population lives within 100 miles of a coastline.

Fig. 11–9 Shift of biomes away from equator Trees can shift 5mi/10years through seed dispersal Shift of habitat to higher latitudes and elevations Potential large loss of biodiversity © Brooks/Cole Publishing Company / ITP

Don’t forget!

How would you rank these possible effects of climate change: which would you say is the greatest concern and why?