* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Introduction - San Jose State University
German Climate Action Plan 2050 wikipedia , lookup
Joseph J. Romm wikipedia , lookup
Soon and Baliunas controversy wikipedia , lookup
Climate resilience wikipedia , lookup
Climate change mitigation wikipedia , lookup
ExxonMobil climate change controversy wikipedia , lookup
Heaven and Earth (book) wikipedia , lookup
Climatic Research Unit documents wikipedia , lookup
Climate engineering wikipedia , lookup
Citizens' Climate Lobby wikipedia , lookup
Effects of global warming on human health wikipedia , lookup
Climate change adaptation wikipedia , lookup
Climate change denial wikipedia , lookup
Economics of global warming wikipedia , lookup
Climate governance wikipedia , lookup
Low-carbon economy wikipedia , lookup
General circulation model wikipedia , lookup
Climate change and agriculture wikipedia , lookup
Climate change in Tuvalu wikipedia , lookup
Global warming controversy wikipedia , lookup
Carbon Pollution Reduction Scheme wikipedia , lookup
Effects of global warming wikipedia , lookup
Physical impacts of climate change wikipedia , lookup
Fred Singer wikipedia , lookup
Effects of global warming on humans wikipedia , lookup
Instrumental temperature record wikipedia , lookup
Global warming hiatus wikipedia , lookup
Media coverage of global warming wikipedia , lookup
Mitigation of global warming in Australia wikipedia , lookup
Climate change in the United States wikipedia , lookup
Climate sensitivity wikipedia , lookup
Climate change and poverty wikipedia , lookup
Scientific opinion on climate change wikipedia , lookup
Effects of global warming on Australia wikipedia , lookup
Global warming wikipedia , lookup
Climate change, industry and society wikipedia , lookup
Attribution of recent climate change wikipedia , lookup
Politics of global warming wikipedia , lookup
Surveys of scientists' views on climate change wikipedia , lookup
Climate change feedback wikipedia , lookup
Public opinion on global warming wikipedia , lookup
Business action on climate change wikipedia , lookup
MET 112 Global Climate Change - Lecture 8 Radiative Forcing Eugene Cordero San Jose State University Outline GHG/Aerosols Radiative Forcing Activity 1 MET 112 Global Climate Change In the reading for the week, what does the author find in his breakfast? 1. Evidence of ancient trees 2. Fossil fuels 3. Ozone depleting substances 4. Evidence of mercury pollution 5. Carbon dioxide 6. Both 1 and 4 7. Both 3 and 5 100% 0% 0% 0% il le fu t nc in el s g e su of b. m .. er cu C ar ry bo ... n di ox B ot id h e 1 an B ot d h 4 3 an d 5 0% de p Ev ne zo O MET 112 Global Climate Change id e e nc id e Ev 0% ss Fo of an c ie n tt ... 0% 2 Climate Change: how much and in what direction? We have studied the various factors that contribute to climate change. Some of these contribute to warming the climate Some of these contribute to cooling the climate It would be helpful if we could develop a tool for measuring the strength of the various warming and cooling factors. The Radiative Forcing calculation is a tool for measuring how climate will change due to a particular forcing mechanism. 4 MET 112 Global Climate Change 5 MET 112 Global Climate Change Anthropogenic Forcing Without doubt, humans have altered the radiative balance of the Earth system. The changes can be partitioned into the following categories: – Enhanced greenhouse gases CO2, CH4, N2O, CFC’s – Ozone Tropospheric Stratospheric – Aerosols (Natural and Anthropogenic) First part of Sulfate today’s lecture Carbon Biomass burning (black carbon) – Land Use Changes 7 MET 112 Global Climate Change Atmospheric Aerosols Microscopic liquid/solid particles – Natural sources - examples: Volcanoes (sulfur) Fires, dust – Dust, sulfate particles reflect incoming sunlight: ___________________ Cool atmosphere – Smoky soot absorb incoming sunlight: ____________________ warm atmosphere 9 MET 112 Global Climate Change 10 MET 112 Global Climate Change 11 MET 112 Global Climate Change Aerosols (II) Natural sources include: – Dust, sea salt and volcanic emissions Anthropogenic sources include – Automobiles, factories and biomass burning. Biomass burning: – Anthropogenic portion: burning of large forests for agriculture Aerosols have ‘short’ relative lifetimes – They can ‘float’ around for a few days to a week or two. Aerosols affect the Earth’s energy balance by – reflecting incoming energy and/or – absorbing incoming shortwave and longwave radiation. Cooling influence is stronger 13 MET 112 Global Climate Change Aerosols (III) There are three major types of aerosols – Sulfate aerosols – Black carbon aerosols – Organic carbon aerosols – All have been increasing in concentration over the last 150 years – the industrial revolution. 15 MET 112 Global Climate Change Aerosol Observations from NASA Satellite 16 MET 112 Global Climate Change 17 MET 112 Global Climate Change 18 MET 112 Global Climate Change Sulfate Aerosols Natural source: volcanoes Anthropogenic sources: burning of fossil fuels 90% of sulfur aerosols are anthropogenic Example: SO2 (sulfur dioxide– From coal combustion Sulfate aerosols increasing globally Sulfate aerosols reflect incoming solar radiation. Total effect on Earth’s energy budget – Cooling – Radiative Forcing: negative 20 MET 112 Global Climate Change Black Carbon (Aerosols) Natural source: – Natural biomass burning Anthropogenic source – incomplete combustion from coal and diesel engines; biomass burning Also know as - ‘Elemental Carbon’ or ‘soot’ Black carbon absorbs solar radiation – It’s black so has a low albedo (can also affect snow when it falls to the ground). Potentially harmful if inhaled. Total effect on Earth’s energy budget – Warming – Radiative Forcing: positive MET 112 Global Climate Change 22 Organic Carbon (Aerosols) Natural source – Natural biomass burning Anthropogenic source – Burning fuel – Biomass burning Produced as a result of incomplete combustion. These aerosols are reflective Total effect on Earth’s energy budget – Cooling – Radiative Forcing: negative 24 MET 112 Global Climate Change Indirect Effect due to aerosols (I) Certain aerosols may enhance cloud production and character Recall how clouds form – Water vapor condenses to liquid water – This processes requires ‘cloud condensation nuclei’ – Examples of cloud condensation nuclei Dust, salt, smoke (all of which are natural aerosols) So, aerosols (with both natural and anthropogenic origin) – may serve as cloud condensation nuclei. MET 112 Global Climate Change 26 Indirect Effect due to aerosols (II) More cloud condensation nuclei – would enhance cloud production The question then is how would clouds change – Current understanding is that This idea of enhanced cloud formation by increases in aerosols is termed – The ‘indirect effect’ of aerosols Understanding of these processes is currently incomplete. – But model results suggest more low clouds and thus Total effect on Earth’s energy budget – – – Cirrus cloud (high clouds) production possible, but still MET 112 Global Climate Change uncertain how important. 27 Indirect Effect due to aerosols (II) More cloud condensation nuclei – would enhance cloud production The question then is how would clouds change – Current understanding is that This processes would increase cloud albedo This idea of enhanced cloud formation by increases in aerosols is termed – The ‘indirect effect’ of aerosols Understanding of these processes is currently incomplete. – But model results suggest more low clouds and thus Total effect on Earth’s energy budget – Cooling – Radiative Forcing: negative – Cirrus cloud (high clouds) production possible, but still MET 112 Global Climate Change uncertain how important. 28 Weather, Aerosols and Climate – film clip 30 MET 112 Global Climate Change Over the last 250 years, CO2 concentrations have increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, CH4 concentrations have increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, CFC concentrations have increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, black carbon aerosol concentrations have increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, the earth’s albedo has changed as a result of deforestation. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, organic carbon aerosol concentrations have increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, the amount of low clouds in the atmosphere has increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, the intensity of the sun’s incoming radiation has increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Over the last 250 years, aircraft induced high clouds have increased. The earth’s surface would therefore 1. Receive more energy resulting in warming 2. Receive less energy resulting in cooling 3. Stay the same 100% 0% iv ec e R R ec e iv e e sa m th e St ay le s s m or e en en er gy er gy r.. . ... e 0% Radiative Forcing: Positive Values: Negative Values: Radiative Forcing: Positive Values: Warming the Earth’s surface Negative Values: Cooling the Earth’s Surface Radiative Forcing A change imposed upon the climate system which modifies the Earth’s energy (radiative) balance. Radiative forcing is usually given in units of – watts per square meter (W/m2), Positive values of radiative forcing – contribute to heating of the surface, Negative values of radiative forcing – Contribute to cooling of surface. 43 MET 112 Global Climate Change 44 MET 112 Global Climate Change Radiative Forcing Examples of radiative forcing mechanisms include – Changes in solar intensity – Volcanic activity – Changes in atmospheric composition CO2 Aerosols Ozone – Changes in land surfaces 46 MET 112 Global Climate Change Radiative Forcing Changes in these mechanisms – produce changes to the earth energy budget. The magnitude of the radiative forcing determine how strong the effect is. Radiative forcing is computed by comparing – Pre-industrial energy balance (1750) with today’s energy balance (2000) 48 MET 112 Global Climate Change Enhanced Greenhouse Gases Greenhouse gas concentrations have increased over the last 150 years dramatically The main anthropogenic contribution to greenhouse gases concentrations include: CO2, CH4, N2O, CFC’s (Halons) Increases in greenhouse gas concentrations are well observed Radiative Forcing: positive 50 MET 112 Global Climate Change Ozone Ozone exists in upper atmosphere – Ozone layer (stratospheric ozone) – Ozone layer protects the earth from harmful UV radiation – Ozone layer responsible for heating the stratosphere – Stratospheric ozone levels have been declining over last 20 years (ozone depletion) – Radiative Forcing: negative Ozone exists in lower atmosphere – Tropospheric ozone is another word for ‘smog’ – Tropospheric ozone levels have increased over last 50 years. – Radiative Forcing: positive 52 MET 112 Global Climate Change Land Use Change Changes in the land use have contributed to – Albedo changes Deforestation has been largest contributor High latitudes have been most affected – Pre Industrial: Snow covered forests (low albedo) – Current: Open snow covered areas (high albedo) Again, large uncertainties remain Radiative Forcing: negative 54 MET 112 Global Climate Change Radiative Forcing from the IPCC 1 2 3.0 3 4 5 -1.4 6 7 8 9 10 Radiative Forcing from the IPCC What does this part of the diagram mean? Radiative Forcing from the IPCC What does this part of the diagram mean? Increases between 1750 through today have caused a 1.66 Watts per meter squared increase in the earth’s radiation budget. This by itself would warm the earth’s surface. Radiative forcing = 1.49 – 1.83 (average is 1.66) Example Imagine you and your partner get offers to work for a new progressive company. They use a pay scale with ‘incentives’. You will get paid: $35,000 5,000 depending on your performance and your partner will get paid $75,000 60,000 . Calculate you are your partner’s total salary. – The total (combined) salary is with no ‘incentives’: – Your salary ranges from – Your partner’s salary ranges from Maximum possible salary: Minimum possible salary: So, the total salary is between Big uncertainity! Example Imagine you and your partner get offers to work for a new progressive company. They use a pay scale with ‘incentives’. You will get paid: $35,000 5,000 depending on your performance and your partner will get paid $75,000 60,000 . Calculate you are your partner’s total salary. – The total (combined) salary is with no ‘incentives’: = $110,000 – Your salary ranges from $30,000 to 40,000 – Your partner’s salary ranges from $15,000 to 135,000 Maximum possible salary: $175,000 Minimum possible salary: $45,000 So, the total salary is between $45,000 – 175,000 Big uncertainity! Terms in the radiative forcing diagram Term 1-2: Increases in CO2, CH4, N2O and CFCs – producing warming (positive) Term 3: Decreases in upper atmospheric ozone (ozone depletion) – provide less heating of upper atmosphere (negative) Increases in lower atmosphere ozone – produce warming (positive) Term 4: Increases in water vapor (due to extra CH4) – produce warming (positive) Term 5: Changes in Albedo – Increases in black carbon: produce warming (positive) – Increase in surface albedo (deforestation): produce cooling (negative) Term 6: Increases in sulfate aerosols – produce cooling (negative) MET 112 Global Climate Change 62 Terms in the radiative forcing diagram Term 7: Increases in aerosols altering cloud properties (more low level clouds) – produce cooling (negative) Term 8: Increases in aircraft induced high clouds (contrails) – produce warming (positive) Term 9: Increases in the strength of the sun – produce warming (positive) Term 10-11: Increases in aircraft induced high clouds (contrails and cirrus clouds) – produce warming (positive) Term 10: Total anthropogenic forcing – Produce warming (positive) MET 112 Global Climate Change 64 Radiative Forcing example Imagine that the only two radiative forcing terms are changing the climate are: – CO2 – Ozone Depletion Mean: 1.6, range: (1.49 – 1.82) Mean: -0.15, range(-0.15 – 0.05) Calculate the radiative forcing just due to those two terms including the uncertainties: Mean = 1.6+ (-0.15)=1.45 Calculate range of values Min: 1.49+(-0.15)=1.34 Max: 1.82+0.05=1.87 RF = 1.45 (1.34 – 1.87) 65 MET 112 Global Climate Change Activity 1. Calculate the total mean radiative forcing from the provided figure of individual radiative forcing from the IPCC. Please show your work! 2. Calculate the total range of possible values from the above calculation. 3. What conclusions does the total mean radiative forcing tell us about how the climate has changed? 4. How does the range of values (or uncertainties) affect our above conclusions? 66 MET 112 Global Climate Change What is the mean radiative forcing Between -5 and -3 W/m2 Between -3 and -1 W/m2 Between -1.0 and -0.1 W/m2 Between 0 and 1.0 W/m2 Between 1.0 and 2.0 W/m2 Between 2 and 4 W/m2 Between 4 and 6 W/m2 100% 0% 0% 0% 0% 0% d an ee n -3 et w ee n B et w B et w ee n -5 an d -3 W /m 2 B 1 -1 et W . w ee 0 a /m n n 2 d B 0 et an -0.1 w d ... ee 1. n 0 B 1. W et 0 w /m a ee nd 2 n B 2. 2 et 0. an w .. ee d n 4 W 4 an /m d 2 6 W /m 2 0% B 1. 2. 3. 4. 5. 6. 7. MET 112 Global Climate Change 67 Q3: What conclusions does the mean forcing tell us 1. Warming forcing outweighs cooling 2. Cooling forcing outweighs warming 3. Human induced warming is much stronger than naturally forced warming. 4. Both 1 and 3 5. Both 2 and 3 100% H um 3 d B ot h 2 an d an 1 ot h B an in d uc e d w ou ng fo rc i in g oo l C ar m i.. ... tw t.. . ou ng fo rc i in g W ar m MET 112 Global Climate Change 0% 0% 0% 3 0% 70 Q4: What conclusions does the range of radiative forcing tell us 5. 6. 7. 8. 0% 0% 0% 0% 0% 0% 0% w ar m in e g co fo ol rc in Th in g g e fo is ea rc m rt in h Th or g sh ... is e ou co m or ld ol e in be ... g w is ar st m ro in ng .. er th an Bo ... th 1 Bo and th 3 1 Bo and th 4 2 a nd Bo th 3 2 an d 4 4. Th 3. 100% e 2. The warming forcing is more certain than the cooling. The cooling forcing is more certain than the warming. The earth should be warming, but by how much is difficult to say because of the uncertainty of the cooling factors. The cooling is stronger than the warming and thus the earth should cool. Both 1 and 3 Both 1 and 4 Both 2 and 3 Both 2 and 4 Th 1. MET 112 Global Climate Change 71 End of Lecture Energy Balance The Earth’s atmosphere and surface are in radiative balance: – Energy coming in = energy going out This balance is true everywhere: – At the earth’s surface – At the top of the atmosphere – Within the atmosphere 76 MET 112 Global Climate Change 77 MET 112 Global Climate Change 78 MET 112 Global Climate Change 79 MET 112 Global Climate Change Activity 12 In the IPCC estimate of the Earth’s energy balance, show how the earth’s energy balance is maintained at the: A) Top of the atmosphere B) Within the atmosphere C) Earth’s surface Be sure to indicate how the energy is balanced (using numbers) and where that energy comes from at each level. 80 MET 112 Global Climate Change What is the energy balance at the top of the earth’s atmosphere? 1. 2. 3. 4. 342 Wm-2 in, 235 Wm-2 out 342 Wm-2 in, 342 Wm-2 out 107 Wm-2 in, 235 Wm-2 out 77 Wm-2 in 77 Wm-2 out MET 112 Global Climate Change ou W 77 W m -2 in in , 77 W m -2 7 10 m -2 W m .. 23 5 W m .. 34 2 in , W m -2 2 34 2 34 0 of 70 W m -2 in , 23 5 W m .. t 0% 0% 0% 0% 81 What is the energy balance at the Earth’s surface? 1. 2. 3. 4. 324 Wm-2 in, 390 Wm-2 out 168 Wm-2 in, 168 Wm-2 out 522 Wm-2 in, 522 Wm-2 out 492 Wm-2 in 492 Wm-2 out MET 112 Global Climate Change in 49 2 W m -.. . W m .. 2 49 52 2 W m -2 W m -2 in , 52 2 W m .. 16 8 in , W m -2 8 16 4 32 0 of 70 W m -2 in , 39 0 W m .. 0% 0% 0% 0% 82 What is the energy balance within the atmosphere? 1. 2. 3. 4. 596 Wm-2 in, 596 Wm-2 out 519 Wm-2 in, 519 Wm-2 out 350 Wm-2 in, 350 Wm-2 out 492 Wm-2 in 492 Wm-2 out MET 112 Global Climate Change in 49 2 W m -.. . W m .. 2 49 52 2 W m -2 W m -2 in , 52 2 W m .. 16 8 in , W m -2 8 16 4 32 0 of 70 W m -2 in , 39 0 W m .. 0% 0% 0% 0% 83