CLIMATE CHANGE

Earth’s Climate Has Undergone Many Changes Warm Cold Icy Not icy Cambrian ‘explosion’ of life Today

Currently in a warming period Rate of warming is exceptional Cause is too

Air Temps Vary, But The Trend Is Clear

Increasing Rates Of Warming Compare line slope

Temperature is correlated with CO2

CO2 is a product of fossil fuel use Temperature Fossil Fuel use Lagged means 25 time lag (time for atmospheric build up)

Compounding factor: permafrost methane from the atmosphere. Methane's lifetime in the atmosphere is much shorter than carbon dioxide (CO2), but CH4 is more efficient at trapping radiation than CO2. Pound for pound, the comparative impact of CH4 on climate change is over 20 times greater than CO2 Impact of CH4 is 20x that of CO2

Factoring in all predicted greenhouse gas concentrations The UN Climate Change Report (1/10)

RAMIFICATIONS OF WARMING

Warming Oceans

Coral reef bleaching healthy bleached

Reduced ice cover at the north pole

stampede risk to calves Polar bear more swimming less hunting Walruses were first spotted coming ashore in large numbers in 2007. In 2009, an estimated 3,000 walruses were seen; the number rose to 30,000 in 2011 and went back down to 10,000 in 2013. (Read "Ten Thousand Walruses Gather on Island as Sea Ice Shrinks.") Scientists have seen large haul-outs on the Russian side of the Bering Strait for quite some time, says Anthony Fischbach, a wildlife biologist at the USGS in Anchorage. But since the first recordings of walrus gatherings in Alaska in the 1870s, groups of this size weren't observed until 2007, he said. While it's not unusual for males to gather in large numbers on Alaska's shores, females typically prefer floating ice chunks as places to give birth, leaving calves on the ice when finding food. walrus larger haul-outs stampede risk to calves

Corresponding change in sea level Past 300 years 20th century

Low lying islands/coasts most vulnerable Maldives – 450,000 people The Maldives, consisting of over 1,100 islands to the west of India, is the world's lowest-lying nation. On average the islands are only 1.3 meters above sea level. The 325,000 (plus 100,000 expatriate workers who are not counted in the census) residents of the islands are threatened by rising sea levels. 11 islands that will disappear

Ocean Acidification CO2 + H2O -> carbonic acid

Ecosystem Change both habitat & biota Grinnell resurvey project a century of change Alpine chipmunk Neotamias alpinus

Shifts in climate zones, ecosystems malaria parasite and vector expand range

pushed to highest alpine habitats gone from >33% habitat Pika pushed to highest alpine habitats gone from >33% habitat intolerant of heat The tiny pika, a cousin of the rabbit that lives on mountain peaks in the western United States, is running out of options. In fact, they have already disappeared from over one-third of their previously known habitat in Oregon and Nevada. Now, the situation is so dire that the U.S. Fish and Wildlife Service is considering the pika for protection under the Endangered Species Act. Because these small mammals have adapted to cold alpine conditions, pikas are intolerant of high temperatures and can die from overheating when exposed for just a few hours. Migratory birds

Increased extinctions Golden Toad Increased extinctions EXTINCT: Golden toad (Bufo periglenes). Along with the Monteverde harlequin frog (Atelopus varius), also of Central America, the golden toad is among the very small number of species whose recent extinction has been attributed with medium confidence to climate change, according to Scholes and Pörtner. Last seen in 1989, the golden frog lived in mountaintop cloud forests that have disappeared due to drought and other climatic changes. Other confounding factors are involved, such as the deadly chytrid fungus, which has killed off many amphibians worldwide.

Despite the evidence not all are convinced • International consensus 130 nations • Scientific consensus 1250 scientists • Extensive studies 12,000 papers • Exhaustive peer review 90,000 comments skeptical –> raise questions deny –> refuse Author: The Greatest Hoax: How the Global Warming Conspiracy Threatens Your Future. (2012) US senator J. Imhofe, OK Environmental and Public Works Committee

How to proceed? Opposing claims: • Global warming • No global warming Opposing actions: • act now to reduce greenhouse gas emissions • take no action 1 3 4 2 1 3 Discuss/record on whiteboards the consequences of each pair 2 4

http://www. livescience. com/common/media/video/player. php http://www.livescience.com/common/media/video/player.php?videoRef=GoldilocksGreen (6 min) http://videos.howstuffworks.com/hsw/22369-extreme-climate-the-role-of-the-greenhouse-effect-video.htm (6min) Look for more at How Stuff Works Sci Amer Frontiers http://www.hulu.com/watch/23343/scientific-american-frontiers-hot-planet-%E2%80%93-cold-comfort (22 min) http://www.movieweb.com/tv/TVLsmRLNaWMHQM/season-20-earth-day-message-heating