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MET 112 Global Climate Change - Lecture 10 Recent Climate Change Dr. Eugene Cordero San Jose State University Outline Recent trends in temperature Recent trends in GHGs Time scales 1 MET 112 Global Climate Change (b) Additionally, the year by year (blue curve) and 50 year average (black curve) variations of the average surface temperature of the Northern Hemisphere for the past 1000 years have been reconstructed from “proxy” data calibrated against thermometer data (see list of the main proxy data in the diagram). The 95% confidence range in the annual data is represented by the grey region. These uncertainties increase in more distant times and are always much larger than in the instrumental record due to the use of relatively sparse proxy data. Nevertheless the rate and duration of warming of the 20th century has been much greater than in any of the previous nine centuries. Similarly, it is likely7 that the 1990s have been the warmest decade and 1998 the warmest year of the millennium. Examples of Temperature Change Trends Periodic Oscillations Random Variations Jumps 3 MET 112 Global Climate Change Examples of Temperature Change Draw the following: 1. 2. 3. 4. 5. 6. 7. Trend Oscillation Trend + Oscillation Random variations Random + trend Jump Random + jump 4 MET 112 Global Climate Change Trend Temperature 0 20 40 60 MET 112 GlobalTime Climate Change 80 100 5 Graph Time60 100 0 20 40 80 100 0 20 40 Time60 80 100 Time60 0 20 40 Time60 80 100 0 20 40 80 100 Temperature 80 Temperature 40 Temperature 20 Temperature Temperature Temperature 0 0 20 40 Time60 80 100 Time60 This graphs represents 0 20 40 Time 60 80 96% tio n an R an do m va lla tio n sc i d+ O Tr en R d ill a sc Tr en 0% 0% 0% 0% ria tio do n m +T re nd R Ju an m do p m +J um p 4% 0% O Trend Oscillation Trend+Oscillation Random variation Random+Trend Jump Random+Jump Temperature 1. 2. 3. 4. 5. 6. 7. 100 0 20 40 Time 60 80 69% 13% 9% 4% 2% 2% ria tio do n m +T re nd R Ju an m do p m +J um p tio n R an va lla an do m d+ O sc i tio n 0% R d ill a sc O Tr en Trend Oscillation Trend+Oscillation Random variation Random+Trend Jump Random+Jump Tr en 1. 2. 3. 4. 5. 6. 7. Temperature This graphs represents 100 0 20 40 Time 60 80 83% 11% 4% 0% ria tio do n m +T re nd R Ju an m do p m +J um p tio n an R an do m va lla sc i d+ O R d ill a sc Tr en 2% 0% tio n 0% Tr en Trend Oscillation Trend+Oscillation Random variation Random+Trend Jump Random+Jump O 1. 2. 3. 4. 5. 6. 7. Temperature This graphs represents 100 0 20 40 Time 60 96% R an va do m an 0% 4% 0% ria tio do n m +T re nd R Ju an m do p m +J um p tio n 0% lla sc i d+ O R d ill a sc O 0% tio n 0% Tr en Trend Oscillation Trend+Oscillation Random variation Random+Trend Jump Random+Jump Tr en 1. 2. 3. 4. 5. 6. 7. Temperature This graphs represents 80 100 0 20 40 Time 60 80 93% 7% R an va do m an 0% 0% ria tio do n m +T re nd R Ju an m do p m +J um p tio n 0% lla sc i d+ O R d ill a sc O 0% tio n 0% Tr en Trend Oscillation Trend+Oscillation Random variation Random+Trend Jump Random+Jump Tr en 1. 2. 3. 4. 5. 6. 7. Temperature This graphs represents 100 0 20 40 Time 60 80 98% R an va do m an 0% 0% 2% ria tio do n m +T re nd R Ju an m do p m +J um p tio n 0% lla sc i d+ O R d ill a sc O 0% tio n 0% Tr en Trend Oscillation Trend+Oscillation Random variation Random+Trend Jump Random+Jump Tr en 1. 2. 3. 4. 5. 6. 7. Temperature This graphs represents 100 Time Frames -- Examples Seconds to minutes – Small-Scale Turbulence Hours – Diurnal Cycle (Caused by Earth’s Rotation) Hours to Days – Weather Systems Months – Seasonal Cycle (Caused by tilt of axis) Years – El Niño Decades -- Pacific Decadal Oscillation Centuries – Warming during 20th Century (Increase in greenhouse gases?) Tens of thousands of Years – Irregularities in Earth’s motions Millions of Years – Geologic Processes 22 MET 112 Global Climate Change …“Over the last 140 years, the best estimate is that the global average surface temperature has increased by 0.6 ± 0.2°C” (IPCC 2001) So the temperature trend is: 0.6°C ± 0.2°C What does this mean? Temperature trend is between 0.8°C and 0.4°C The Uncertainty (± 0.2°C ) is critical component to the observed trend Current CO2: ~380 ppm What Changed Around 1800? Industrial Revolution – Increased burning of fossil fuels Also, extensive changes in land use began – the clearing and removal of forests 27 MET 112 Global Climate Change Burning of Fossil Fuels Fossil Fuels: Fuels obtained from the earth are part of the buried organic carbon “reservoir” – Examples: Coal, petroleum products, natural gas The burning of fossil fuels is essentially – A large acceleration of the oxidation of buried organic carbon 31 MET 112 Global Climate Change Land-Use Changes Deforestation: – The intentional clearing of forests for farmland and habitation This process is essentially an acceleration of one part of the short-term carbon cycle: – the decay of dead vegetation Also causes change in surface albedo (generally cooling) 33 MET 112 Global Climate Change 34 MET 112 Global Climate Change Natural Short-Term Carbon Cycle – Quantitative Carbon Content: 750 Pg* Carbon Flux: ~ 120 Pg/year Atmosphere Carbon Content: 38, 000 Pg Carbon Content: 2000 Pg Biosphere Carbon Flux: ~ 90 Pg/year 1 Pg = 1015 g Ocean 35 MET 112 Global Climate Change Carbon Budget Example Atmosphere 1.5 Note: Number are not real…only for practice Land Land emission =1.3 Ocean emission = 3.0 Ocean Positive values refer to carbon going into the atmosphere Land uptake = -2.3 Ocean uptake = ? What is the ocean uptake required to produce an atmosphere at 1.5? The ocean update is: +1.5 -1.5 -0.5 0 1.0 -1.0 57% 9% 9% 1 -1 22% 4% 5 -0 . MET 112 Global Climate Change 0 5 -1 . 0% 1. 5 1. 2. 3. 4. 5. 6. 39 Carbon Budget Example Atmosphere 1.5 Note: Number are not real…only for practice -1.0 Land Land emission =1.3 Ocean emission = 3.0 -0.5 3.0 Ocean Land uptake = -2.3 Ocean uptake = ? -0.5 What is the ocean uptake required to produce an atmosphere at 1.5? Carbon Budget Example Notes… Land/atmosphere Flux = Land emission + Land uptake Ocean/atmosphere Flux = Ocean emission + ocean uptake Carbon Budget Changes Units in Peta-grams (x1015) of Carbon per year (PgC/yr) Atmosphere increase 3.3 ± 0.1 – Observations Emissions (fossil fuel, cement) 5.4 ± 0.3 – Estimates from industry Ocean-atmosphere flux -1.9 ± 0.6 – Estimates from models/obs Final component is Land/atmosphere flux: What is the land/atmosphere flux? 43 MET 112 Global Climate Change Carbon Budgets Atmosphere 3.3 PgC 5.4 PgC Land Land/atmosphere flux Fossil fuel burning -1.9 PgC Ocean Ocean/atmosphere flux What is the land/atmosphere flux? +4.0 -4.0 -3.5 +3.5 0.2 -0.2 71% 17% MET 112 Global Climate Change -0 . 5 4% 0. 5 -3 . -4 0% 5 2% 3. 5 6% 4 1. 2. 3. 4. 5. 6. 45 Carbon Budgets Atmosphere 3.3 PgC -0.2 PgC Land Land/atmosphere flux 5.4 PgC Fossil fuel burning -1.9 PgC Ocean Ocean/atmosphere flux Carbon Budget (II) Land atmosphere flux – Must be to balance budget -0.2±0.7 Land atmosphere flux partitioned as follows Land use change – From observations 1.7 Residual terrestrial sink Calculated to balance land/atmosphere flux 48 MET 112 Global Climate Change Carbon Budgets Atmosphere 3.3 PgC -0.2 PgC Land use change 1.7 PgC Land 5.4 PgC Fossil fuel burning -1.9 PgC Ocean Land/atmosphere flux So, now considering the land use change, what is the new Land/atmosphere flux? What is the residual land sink? 89% MET 112 Global Climate Change 2% 1. 5 2% 0. 2 7 -1 . 6% 9 -1.9 -1.7 +0.2 1.5 -1 . 1. 2. 3. 4. 50 Carbon Budgets Atmosphere 3.3 PgC -1.9 -0.2 PgC Land use change 1.7 PgC Land 5.4 PgC Fossil fuel burning -1.9 PgC Ocean Land/atmosphere flux So, now considering the land use change, what is the new Land/atmosphere flux? Carbon Budget (II) Land atmosphere flux – Must be to balance budget -0.2±0.7 Land atmosphere flux partitioned as follows Land use change – From observations 1.7 Residual terrestrial sink -1.9 Calculated to balance land/atmosphere flux 52 MET 112 Global Climate Change Human Perturbation of the Carbon Cycle 53 MET 112 Global Climate Change Carbon Budget (III) There are significant uncertainties related to these budget terms. Main questions are related to: – Can biosphere/ocean take up more atmospheric CO2? – What are the carbon fluxes over different types of ecosystems Tropical forests, Temperate forests, Boreal forests, Tropical savannas & grasslands, Temperate grasslands & shrub lands, deserts and semi deserts, Tundra, Croplands, Wetlands – What happens if the land/ocean get ‘saturated’ with carbon? MET 112 Global Climate Change 56 Carbon Budget (III) 58 MET 112 Global Climate Change Greenhouse Gases Carbon Dioxide Methane Nitrous Oxide CFCs (Chlorofluorocarbons) Others 59 MET 112 Global Climate Change Methane 60 MET 112 Global Climate Change Anthropogenic Methane Sources Leakage from natural gas pipelines and coal mines Emissions from cattle – Flatulence…gas Emissions from rice paddies 62 MET 112 Global Climate Change Nitrous Oxide 63 MET 112 Global Climate Change Anthropogenic Sources of Nitrous Oxide Agriculture 64 MET 112 Global Climate Change CFCs CFC-11 CFC-12 65 MET 112 Global Climate Change Sources of CFCs Leakage from old air conditioners and refrigerators Production of CFCs was banned in 1987 because of stratospheric ozone destruction – CFC concentrations appear to now be decreasing – There are no natural sources of CFCs Lecture on ozone depletion to follow later in semester… 67 MET 112 Global Climate Change Latest global temperatures 68 MET 112 Global Climate Change Activity 1. Describe the 120 year temperature records in terms of the seven above described types of variations (trend, trend+oscillation etc.) by breaking up the time series into periods (i.e. from 1930-1950, oscillation + positive trend, from 1950-1970, negative trend) 2. Based on the past 120 years of globally averaged temperatures: a. What trend would you assign to this period. (i.e. 0.3°C over 120 years) b. If you were to break up the data into time sections provide trends over the following time periods i) 1880-1920; b) 1920-1940 and c) 1970-2000 69 MET 112 Global Climate Change How would you describe the last 30 years of temperature Random Oscillation Oscillation+trend Oscillation+jump Random+jump Trend 51% 20% 13% 2% O sc O sc ill d Tr en at io n+ tr en ill d at io n+ ju R m an p do m +j um p n ill at io om MET 112 Global Climate Change 13% 0% O sc an d R 1. 2. 3. 4. 5. 6. 70 What is the approximate temp trend over the last 30 years? 0.6C/30 years 1.0C/30 years .1C/30 years 0.2C/30 years 87% ar s ar s 0 2C /3 0. .1 C/ 3 0 ye ye ar s MET 112 Global Climate Change 4% 2% ye 0 0C /3 1. 6C /3 0 ye ar s 7% 0. 1. 2. 3. 4. 71 What is the approximate temp trend over the last 100 years? 1. 2. 3. 4. 0.08C/10 years 0.8C/10 years 1.0C/10 years .2C/10 years 72 MET 112 Global Climate Change What is the approximate temp trend over the period 1850-1900 1. 0.4C/50 years 2. 0C/50 years 3. -0.4C/50 years 73 MET 112 Global Climate Change 74 MET 112 Global Climate Change Comparison of 1998 with 2005 75 MET 112 Global Climate Change Temperature over the last 10 years 76 MET 112 Global Climate Change The Land and Oceans have both warmed 78 MET 112 Global Climate Change Precipitation patterns have changed 80 MET 112 Global Climate Change Video – Donal MacIntyre and Climate Glacier Cities and climate Future 81 MET 112 Global Climate Change Activity 11 Question Explain how humans may affect precipitation in a city. 82 MET 112 Global Climate Change