FINAL STUDY GUIDE GC
FINAL STUDY GUIDE GC GC 170A
Popular in INTRO TO GLOBAL CHANGE
Popular in Global Studies
This 9 page Study Guide was uploaded by Gigi on Tuesday December 8, 2015. The Study Guide belongs to GC 170A at University of Arizona taught by E. Bigio in Fall 2015. Since its upload, it has received 86 views. For similar materials see INTRO TO GLOBAL CHANGE in Global Studies at University of Arizona.
Reviews for FINAL STUDY GUIDE GC
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 12/08/15
Global Change Final Study Guide Lectures 14,15,16,17 Weather State of the atmosphere at any given place or time Rainstorms, tornadoes, blizzards, hurricanes, heat waves Climate Long term average of weather, refers to typical weather patterns for a place, varies slowly over time Climate Change Long term changes in the regional climate or earth's average temperature occurring over decades to centuries Climate Variability Short term changes in the climate occurring over years to decades usually related to natural climate influences Proxy Methods Used to reconstruct past climates What is proxy data? Data that represents past environments & climates (tree rings, ice cores, pollen records) Why is it important to study • Key to future = understanding past paleoclimate? • Historical info provides a context for recent warming • Helps to predict future environmental conditions What proxy information can be 1. Melt Water= Temperature (hydrogen isotopes) obtained from ice cores? 2. Gas Bubbles= atmosphere samples, used to reconstruct past greenhouse gas concentrations (Carbon dioxide, methane, nitrous oxide) 3. Particulates=dust/ash from past volcanic eruption & pollution What do the Vostok and Dome C Shows repetitive cycles/ fluctuations in CO2 & ice cores show? unprecedented high CO2 levels in recent decades Tree ring width Related to changes in temperature, precipitation and elevation Wide= wet year Narrow=dry year *Distinct Rings: winter- tree shuts down & stops growing Frost rings: Row of damaged cells in middle of tree ring (Happens to temperature sensitive trees at high elevation & cold temps) Four criteria for cross-dating 1. From similar/same location (typically mountain) 2. Influenced by same environmental factor 3. Sensitive trees 4. Minimum of 50 trees -Used to determine how old a tree is -Can’t just count the rings since trees can have false or missing rings (dry years) Why are desert trees not Warmer winters = trees don’t shut down growth = suitable for dendrochronology? Don’t form distinct rings Sensitive Tree Growth Growing on steep slopes & rocky areas *Represent regional changes in rainfall or temperature (Changes cause variation in wide vs. narrow rings) What is a paleoclimate Representation of climate (temperature or precipitation) reconstruction? What do in the past, prior to instrumental records instrumental records show in -Developed from proxy methods from past 150 years recent decades? *Recent Paleoclimate reconstructions have confirmed that 20 century warming is unprecedented What is the evidence of the Medieval Warm Period: Medieval Warm Period and • 900-1300 AD average temperature in northern Little Ice Age? hemisphere was Warmer • Evidence from northern Europe, such as Vikings settled in Greenland for 400 years and archaeologists dig up the remains • Native Americans dispersed since droughts made it difficult to sustain large communities Little Ice Age: • 1400-1800 AD, Regional observations (Europe) • Holland had more continuous frozen ice • Mountain glaciers were more advanced in some locations than they are today • sunspots & increased volcanic activity contributed Sunspots Sun’s shortwave radiation varies over time=changes amount of incoming solar radiation that reaches the earth -Warms the climate slightly for about10 years More sunspots=more solar radiation Sunspots contribute tiny amount to recent warming (Natural cause of climate change) Volcanic Eruptions Emit large amounts of SO2 gas that converts to sulfate aerosols in stratosphere Aerosols = very reflective & blocks incoming solar radiation & cools the climate for 1- 2 years Volcanoes near equator: • Hadley cell circulation transports the aerosols=larger impact on global climate (Natural cause of climate change) Where do Bristlecone pines At high elevations in White Mountains of California (3: grow? Sheep Mt, Campito Mt, Methuselah Walk) & Colorado (2: Almagre Mt, Hermit Lake) • Used for temperature reconstructions Why are bristlecone pines They are sensitive to temperature at high elevations. especially useful for long Shows evidence of past volcanic eruptions: paleoclimate (especially 1. Cooler global temps. 1-2 years=narrow rings temperature) reconstructions? 2. Cold-snaps for 1-2 weeks=frost rings How is Methuselah different? Moisture sensitive site Temperature-Sensitive Pines Higher elevations= growth limited by cold temperatures • Warm summers (long growing season)=wide rings • Cold summers (short growing season)=narrow rings Moisture-Sensitive Pines Lower elevations= trees are limited by precipitation • Wet winters (more rain/snow)=wide rings • Dry winters (less rain/snow)= narrow rings Lectures 18-23 3 Ice Sources 1. Arctic Sea Ice 2. Ice Sheet (Greenland) 3. Mountain Glaciers Two ways that Arctic sea ice has Decreased in: changed in the past 35 years 1. Area 2. Thickness What are the consequences of 1. Reduced Albedo =more radiation absorbed at surface Arctic Sea Ice loss? 2. Change in weather patterns in the arctic -Does not contribute to global sea-level rise -Economically advantageous (new shipping routes will open) Ice Sheets • Ice flows outwards from the center • Snow accumulation & surface melting are measured • Increasing extent of surface melting What are the consequences of • Destabilizes the glacier, leads to further melting ice sheet melting? • Potential for sea-level rise in the future • Not yet a major cause of sea-level rise Why are the glaciers on the east Warm water circulating underneath ice shelf accelerates and west sides of Antarctica melting melting rapidly? What are the two sources of 1. Melting of mountain glaciers & ice sheets current sea-level rise? 2. Thermal expansion of ocean water related to global warming Future predictions 3-4 meters of sea level rise How does warming arctic affect Warming temps = jet stream becomes wavier & slower the jet stream? -Weather patterns become more persistent (NE: more snow CA: drought) Heat Most significant change in daily temperatures is the increasing temperature at night Droughts Defined by: Severity (how dry it is) Length (number of years) Spatial extent How does the 1930’s drought compare with recent droughts in CA or TX? Recent droughts have been severe, but not as widespread as the dustbowl What is a global change type Prolonged & Severe, but less extensive over US drought? Consequences: • Loss of crops • Less water for communities (difficult to generate power) • Forest morality • Wildfires Causes of Drought in CA & SW - Natural variability: La Nina events, Northern Pacific sea surface temperatures - Expansion of Hadley Cell Circulation, Jet Stream Patterns (effects of global warming) Wildfires More wildfires during severe drought years Factors: 1. Severe Drought 2. High Winds Across Western US, number of fires increasing with warming temperatures What is expected for the future • More heat waves with regards to warming • More record temperatures temperatures? • Extreme precipitation & heavy rainfall events Why are extreme precipitation 1. Warmer sea surface temperatures increase events more likely with global evaporation warming? 2. Warmer atmosphere can hold more moisture 3. Clouds move over land & more rainfall occurs Consequences: - Flooding - Crop Damage - Increased water pollution Hurricanes # of hurricanes has not increased over past century & is not expected to Biggest concern: Hurricanes will be more intense & have higher rainfall amounts=more damage Warmer sea surface temperature=higher rainfall amounts Global Climate Change model Computer model that simulates future temperatures based on CO2 emissions - Predicts future temperature changes based on fossil fuel consumption What would the temperature in There would be no increasing trend in the temperature the 20th century be like without without human influence (CO2 emissions from fossil the influence of humans? fuels) Factors that influence future - Population growth CO2 emissions - Economic growth - Technological advances - Political agreements (globalization vs. regionalization) A1 Scenario Global cooperation focused on the economy Mix of fossil fuel & investment in alternative energy B1 Scenario Global cooperation focused on environment Total focus on renewable energy & drastic reductions in CO2 emissions, reaches 2 C o A1B Scenario Most likely because we have global economy (cooperation) with a priority of economic growth with some investment in renewable energy *Exceeds 3 C by 2100 How can we reach a safe level of - Carbon capture & storage 2 C in the future? What are - Afforestation (planting trees) some examples of how we can - Huge investment in renewable (solar/wind) reach the B1 scenario? - Phase out coal Paris Talks Division between developing & industrialized nations • Developing nations need fossil fuel to grow economically & they don’t want to limit growth when industrialized nations caused global warming • Solution requires investment from industrialized nations The Paris negotiations are Future Climate Impacts: focused on keeping the • Cold days/nights will be warmer & less frequent temperature below 2 C. Why is • Hot days/nights will be warmer & more frequent this important? • Frequency of warm spells & heat waves will increase • Frequency of heavy precipitation events will increase What are the stakeholders Energy industry stakeholders focus on cost of action: positions on climate change 1. Economy will suffer greatly policy? 2. Fossil fuel energy is cheap and supports our economy 3. Alternative energies are too expensive Environmental Stakeholders: cost of inaction 1. Cost of disasters 2. Droughts, heat-waves cause economic losses (crop failures) 3. People will migrate, often unexpectedly 4. Alternate energies creates new jobs What do they agree on? Either solution will damage the economy History of Climate Policy 1988: IPCC (intergovernmental panel on climate change, *concluded global warming was occurring) 1990: First climate assessment report (stay at the 1990 level of 350 ppm CO2) 1992: UN convention on climate change 1997: Kyoto Protocol (US didn’t sign) Mitigation Strategies to reduce CO2 emissions • Energy conservation (Compact fluorescent light bulbs, New appliances with energy star ratings, Insulation to homes, seal leaks, Fuel efficient cars, Lifestyle changes: drive less) • Carbon tax • Alternative energy sources (nuclear, wind, solar, hydropower) Adaptation Strategies to protect ourselves from the consequences of climate change • Moving inland, public health programs, changing water management Nuclear Power • Alternative energy (doesn't produce CO2) • Problem #1: creates toxic nuclear waste, difficult to dispose of nuclear waste • Problem#2: risk of major radiation leaks (3 Mile Island 1979, Chernobyl 1986, Fukushima 2011) However, nuclear has a very low death rate compared with fossil fuel sources Benefits of Nuclear Power: • No greenhouse gases • Huge reserves of uranium available • Technology available, produces very little waste • Can provide energy needed in the next 30 years in the transition to renewable energy source Solar Energy Fastest growing renewable energy source in the world • PV (photovoltaic) cells directly convert incoming solar radiation to electricity • When the sunlight is absorbed by the silicon electrons are released from the atoms, that creates electricity 1. Solar Farm: array of solar panels 2. Concentrated solar: series of moveable mirrors, reflect the sun’s energy onto receivers filled with fluid, heat energy from the fluid drives a steam turbine that creates electricity
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'