GC170a1 1st Edition Exam 5 Study Guide Lectures 18 222 Lecture 18 Climate Change impacts Droughts Heat and Fire What is weather The state of the atmosphere at any given place or time What are some examples of weather events Rainstorms Tornadoes Blizzards Hurricanes Heat wave What is climate The long term average of weather in a given place o Refer to typical weather patterns Monsoon rains in Tucson What is a drought Prolonged period of dry weather lack of rainfall that results in a serious water shortage How are droughts defined Severity how dry Length of years Special extent What are recent examples of droughts in the west California currently in severe 3 4 year drought How does the jet stream pattern contribute to current drought in CA The jet stream ridge prevents storms from reaching California for several months and decreases rainfall for multiple years How do these recent droughts compare to the 1930 s and 1950 s droughts Droughts were longer in the past and almost as severe More widespread during the 1930 s and 50 s What is a global change type drought Global Change type drought o A drought episode with warmer temperatures o Leads to more evaporation and drier soils o Regional droughts What are the consequences of prolonged and severe drought e g global change type drought Loss of crops Less water available Forest Mortality Wildfires What is a heat wave And what are the consequences A period of very warm temperatures for a few days to weeks o Consequences Can lead to death in elderly or vulnerable populations Damage to crops and livestock What is happening with daily highs and lows in the past few decades and what does that mean Increases in record high temperatures Increases in night time temperatures Lecture 20 Wildfires at end of Lecture 18 ppt What happened with wildfire activity in 2002 and 2011 2002 severe drought across the intermountain west o Fire activity increased sharply in early 2002 s o Colorado Arizona 2011 severe drought in Texas o Wallow Fire Arizona 841 square miles Biggest wildfire in Arizona 6 000 people evacuated 32 homes destroyed 109 million in fire fighting and damage costs In Texas in 2011 what were the key factors that influenced the Bastrop county complex Exceptional drought that had been ongoing for months Sparks from a powerline started the fire Huge winds because of a nearby tropical storm Consequences o 2 000 homes in one weekend o 2 firefighters were killed o 3 4 billion in fire fighting costs economic losses timber homes infrastructure How are the number of wildfires changing with warmer temperatures of the past 40 years Increase in the number of fires and warmer temperatures across the western US for the past 40 years Warmer temperatures create a longer summer season Lecture 19 Climate Change impacts Extreme storms What is an extreme precipitation event and what are the consequences Extreme storms that brings lots of precipitation in a short period of time o Consequences of heavy or extreme rainfall Flooding Crop damage Increased water pollution What are two examples of extreme rainfall events Tucson July 2006 o Persistent low pressure system brought moisture to southern AZ for four days Brought 10 12 inches of rainfall to southern Arizona Colorado Sept 2013 o 17 inches of rainfall in four days o Annual amount of rainfall in 4 days o Extreme flooding throughout the Front Range Boulder Ft Collins Are extreme precipitation events changing in recent decades Increased occurrence of extreme one day precipitation events over recent years Related to sea surface temperatures why are extreme precipitation events increasing Warmer sea surface temperatures increases evaporation Warmer atmosphere can hold more moisture Clouds move over land and more rainfall occurs Is hurricane activity increasing with warming sea surface temperatures Hurricane activity strength and duration increasing in recent decades with increasing sea surface temperatures What influences the strength or intensity of a hurricane Wind Shear o High wind shear large temperature gradient Warm temperatures at the surface Cool temperatures in the upper atmosphere Intensifies a hurricane Low wind shear similar temperature throughout o Warm temperatures at the surface o Warm temperatures in the upper atmosphere Causes a hurricane to weaken or break apart Is the number of hurricanes increasing over the 20th century look at adjusted hurricane counts It is NOT increasing What is the biggest concern with hurricanes in the future Concern that hurricanes will get more intense and have higher rainfall amounts o Intensity relates to warmer sea surface temperatures leading to a stronger temperature gradient in the atmosphere o Higher rainfall amounts will result from warmer sea surface temperatures leading to increased moisture in the atmosphere How does sea level rise influence the damage during hurricanes Storm Surge o Water being pushed to shore by the storm winds Sensitive to changes in storm intensity and direction Can be more destructive when sea level is higher Lecture 20 C02 sources and emissions scenarios Where do the greenhouse gases come from CO2 o Burning of fossil fuels coal natural gas and oil o Sectors that contribute most to CO2 emissions Industry Transportation Electricity generation CH4 Methane Nitrous Oxide N2O o Methane mostly comes from cattle and rice cultivation o N2O mostly comes from fertilizers o Increases in these have been modest in past few decades What are the fossil fuels Coal oil natural gas o Plant matter buried and compressed into rocks millions of years ago o Oil and natural gas are liquids and stored within sedimentary rocks beneath surface o Coal is compressed plant matter that is solid rock Why does our economy rely so much on fossil fuels The United States gets 81 of energy from fossil fuels a little bit from renewable resources o Cheap o Demand always increasing What is a global climate model GCM Global climate models GCM simulate future temperatures based on CO2 emissions How does it work Simulate the components of the energy budget and atmosphere Change CO2 concentrations and surface properties o Predict temperatures What do GCM s predict for the future Temperature Atmosphere and energy budget How do we know that GCM s are good at reproducing and predicting temperature Can reproduce the influence of human fossil fuels and natural volcanoes sunspots forcings on temperature Separate out the influence of the humans fossil fuels GCM s model the temperature