* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download CO 2
Effects of global warming on human health wikipedia , lookup
Snowball Earth wikipedia , lookup
Climate change and agriculture wikipedia , lookup
Media coverage of global warming wikipedia , lookup
Global warming controversy wikipedia , lookup
Effects of global warming on humans wikipedia , lookup
Climate engineering wikipedia , lookup
Climate sensitivity wikipedia , lookup
Climate change and poverty wikipedia , lookup
Scientific opinion on climate change wikipedia , lookup
General circulation model wikipedia , lookup
Global warming hiatus wikipedia , lookup
Fred Singer wikipedia , lookup
Surveys of scientists' views on climate change wikipedia , lookup
Effects of global warming on Australia wikipedia , lookup
United Nations Framework Convention on Climate Change wikipedia , lookup
Mitigation of global warming in Australia wikipedia , lookup
Climate change in the United States wikipedia , lookup
Climate change, industry and society wikipedia , lookup
Public opinion on global warming wikipedia , lookup
Instrumental temperature record wikipedia , lookup
Global warming wikipedia , lookup
Physical impacts of climate change wikipedia , lookup
Politics of global warming wikipedia , lookup
Attribution of recent climate change wikipedia , lookup
Years of Living Dangerously wikipedia , lookup
IPCC Fourth Assessment Report wikipedia , lookup
The Greenhouse Effect & Global Warming Earth and the Other Terrestrial Worlds How do Greenhouse Gases Make it Warmer? CO QuickTime™ and a 2 TIFF (Uncompressed) decompressor are needed to see this picture. Climate History of Venus Venus should have outgassed as much H2O as Earth. • Early on, when the Sun was dimmer, Venus may have had oceans of water Venus’ proximity to the Sun caused all H2O to evaporate. • • • • H2O caused runaway greenhouse effect surface heated to extreme temperature CO2 released from rocks: Adds to greenhouse effect UV photons from Sun dissociate H2O; H2 escapes, O is stripped If Earth moved to Venus’ Orbit Venusian Weather Today • Venus has no seasons to speak of. • rotation axis is nearly 90º to the ecliptic plane • Venus has little wind at its surface • rotates very slowly, so there is no Coriolis effect • The surface temperature stays constant all over Venus. • thick atmosphere distributes heat via two large circulation cells There is no rain on the surface. • it is too hot and Venus has almost no H2O Venusian clouds contain sulfuric acid! • implies recent volcanic outgassing? Mars’ Thin Atmosphere Martian sunset illustrates just how thin the Martian atmosphere is. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Martian Weather: N Polar Ice Cap & Dust Storm Martian Weather Today • Seasons on Mars are more extreme than on Earth • Mars’ orbit is more elliptical • CO2 condenses & vaporizes at opposite poles • changes in atmospheric pressure drive pole-to-pole winds • sometimes cause huge dust storms QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. The last decade of the 20th Century was the warmest in the entire global instrumental temperature record, starting in the mid-1800’s. All 10 years rank among the 15 warmest, and include the 6 warmest years on record. Through the reconstruction of past climate we can evaluate the rarity and magnitude of this warming. Greenhouse Warming The Greenhouse Effect Physics of Climate Climate Forcing Climate Change Response Uncertainties 4.6 Billion Years Ago ... Venus Earth Mars SUN 0.7 AU 1 AU (150 million km from Sun) 1.5 AU Temperature: Top of Atmosphere decreases with distance from Sun 500 Temperature (Celsius) 500 400 Earth -18oC (0oF) 300 300 200 100 Venus 100 0 Mars 0 0 0 AU -100 -100 -100 5500 oC 0.2 0.4 0.6 0.8 Distance From Sun 1 1 AU 1.2 1.4 1.6 EARTH: Surface 15oC (60oF) Top of Atm: -18oC (0oF) Temperature (Celsius) 500 500 400 300 300 Surface 200 All three phases of water 100 100 0 0 0.5 No Greenhouse1 1.5 2 -100 -100 Surface warmer than top of atm Greenhouse Effect Clue: atm composition Mass & Composition of Atmospheres n2 CO2: <0.04% o2 co2 Earth H2O: <4%h2o CO2: 95% O2: 21% 1 2 3 Venus: 95 atm 4 N2: 78% Mars: 0.006 atm Mars n2 o2 Earth: 1 atm co2 h2o CO2 Greenhouse Warming Goldilocks and the Greenhouse Effect Physics of Climate Climate Forcing Climate Change Response Uncertainties The Electromagnetic Spectrum Wavelength l c = l x freq. = 3 x 108 m/s in vacuum Wavenumber = 1/ wavelength ( cm-1) Frequency in GHz (1 Hz = sec –1) Energy Vibrational Modes for CO2 n1 symmetric n2 bending 15 mm n2 asymmetric 4.3 mm O C O O C O O C O Greenhouse effect: Radiation at specific wavelengths excite CO2 into higher energy states. Light energy is absorbed by the CO2 molecules Other Greenhouse Gases O H O H O O ozone water H N O N H C H H nitrous oxide methane Absorption by different molecules l = 0-15 µm Absorption CO2 Bending Mode Transmission Peak terrestrial emission at ~300K Earth Spectrum Incoming from Sun: High energy, short wavelength Top of Atm Surface 0.5 mm Theoretical Planck curve T= 300 K Infrared ! Radiance measured At top of atm 20 Outgoing from Earth Low energy Long wavelength 10 Incoming Light: Peaks at 0.5 microns Thermal Emission by Earth: Peaks at ~15 microns. Energy Balance Energy Balance at Top of Atmosphere: Incoming shortwave = Outgoing longwave Incoming Shortwave absorbed: Fo (1 – albedo) High albedo: Clouds (~10 mm), ice, deserts Outgoing longwave (IR) radiation: High clouds radiate less due to lower Temp Greenhouse Warming Goldilocks and the Greenhouse Effect Physics of Climate Climate Forcing Climate Change Response Uncertainties Carbon Dioxide: in our atmosphere is Increasing rapidly Worldwide CO2 Emission By fuel type: 1970 - 2020 QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Burning coal QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Quic kTime™ and a TIFF (Unc ompres sed) dec ompres sor are needed to see this pic ture. CO2 Causes Global Warming: Stay tuned . . . gasoline Natural gas Increase in Temperature tracks Increase in Greenhouse Gases Since 1850: Atmospheric CO2 has increased by 30% Temperture vs Time 1850 Year 2000 Three Perspectives on Global Warming Kyoto Protocol: unfccc.int/resource/convkp.html White House Council on Environmental Quality: www.whitehouse.gov/ceq Pew Center on Global Climate Change: www.pewclimate.org CO2 Since the Year 1000 AD CO2 in atmosphere, measured in thick arctic ice. Greenhouse Warming Goldilocks and the Greenhouse Effect Physics of Climate Climate Forcing Climate Change Response Uncertainties Increase in both atm and ocean heat content since 1945: unlikely caused by natural variability and redistribution of heat Retreat of Glaciers QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. 1948 2002 2006 Trift Glacier, Gadmental, Berner, Oberland Switzerland 1939 Franz Josef Glacier In Retreat QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. 1951 1964 1960 QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Franz Joseph glacier New Zealand Length Today QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Franz Joseph Glacier New Zealand Notice how the rock projecting from the valley wall on the left of the picture has been smoothed and ground by the glacier, which covered it 50 years ago, and for many centuries before that. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Longitudinal grooves in the rock are characteristic of glacial carving. Vegetation has begun to cover it now and the grooves are harder to see than in 1964. Receding Glaciers Glacier Length (km) South Cascade Glacier in Washington. The yellow line indicates the location of the terminus in 1958. The red line shows the position of the terminus in 1998. 1500 2000 Temperature trend not caused by solar variability Measurements of solar irradiance: •Solar-min solar-max cycle •Offsets among instruments •No trend Global Warming Hot political issue. More research needed on amount of warming caused by human production of CO2. Three Facts are Absolute: 1. 2. 3. Earth has warmed by 0.5C in past 50 years. Temperature rise greatest in past 10 years. Humans are increasing by 30-50% the CO2 in the atmosphere. Rising CO2 will cause rising temperatures Key Question: How much are humans contributing to Global warming ? Greenhouse Warming Goldilocks and the Greenhouse Effect Physics of Climate Climate Forcing Climate Change Response Uncertainties Predicting Feedback Temp rise ==> Evaporation of ocean water. H2O is a greenhouse gas ==> Earth gets even Warmer ! But clouds may form, increasing albedo. ==> Earth cools. Difficulties in Predicting Feedback Temp rise causes polar cap ice to melt. Artic ground exposed: dirt absorbs more sunlight (lower albedo). Ground warms up more: Earth gets hotter. More polar cap ice melts. Earth gets even hotter. Consequences of Global Warming 1. More evaporation of oceans: More storms, and more severe storms. 2. Water in oceans exand with rising Temp. Sea level has already risen 20 cm in past 100 years. Coastal regions and islands flood. 3. Polar caps and Glaciers melt: Causes rising ocean levels. 4. Change in ocean current patterns. Desserts may get rain; Farmland may get none. By how much will temperatures change over the next 100 years? CO2 (t) D T_surf Different emission scenarios DEPENDS ON MAGNITUDE OF FEEDBACK AND RATE OF INCREASE OF GHG. IN 100 YEARS, FORCED CLIMATE CHANGE WILL MOST LIKELY EXCEED NATURAL VARIABILITY Global Climate Models used to project climate change from different CO2 scenarios: Business as usual CO2 emission Stabilization of CO2 Control Arctic is Warming at Twice Global Rate The Arctic will lose 50% to 60% of its ice distribution by 2100, according to the average of five climate models run by the scientists. One of the five models predicts that it will no longer have any ice in the summer. Positive feedback. Snow and ice reflect 80% to 90% of solar radiation back into space. But when these white surfaces disappear, more solar radiation is absorbed by the underlying land or sea as heat. This heat, in turn, melts more snow and ice. The Kyoto Agreement The Kyoto Protocol, negotiated by more than 160 nations in 1997, will reduce emissions of certain greenhouse gases (primarily CO2). Each of the participating developed countries must decide how to meet its respective reduction goal. Signed by every country in the European Union, by Japan, and by Russia. Kyoto Agreement: The United States Won’t Sign In March 2001, President Bush announced that the United States would not be a party to the Kyoto Protocol on Global Climate Change. The Protocol requires signatories to cut carbon dioxide emissions an average of 5 percent below 1990 levels between 2008 and 2012. Developing nations are exempt from emission reductions. “President Bush strongly opposes any treaty or policy that would cause the loss of a single American job, let alone the nearly 5 million jobs Kyoto would have cost.” - James Connaughton, chairman of the White House council on Environmental Quality. http://www.eia.doe.gov/oiaf/1605/vrrpt/summary/longform.html United States Policy on CO2 “Voluntary Reductions” Three Perspectives on Global Warming Kyoto Protocol: unfccc.int/resource/convkp.html White House Council on Environmental Quality: www.whitehouse.gov/ceq Pew Center on Global Climate Change: www.pewclimate.org Marcy Stopped Here. Ozone QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Ozone formation - ultra-violet radiation from the sun (shown in yellow) splits oxygen molecules into oxygen atoms which then react with more O2 to form ozone. Another molecule (M) is needed to absorb some of the huge amount of energy involved in the reaction. Formation of ozone: Without ozone in the sttratosphere, life would not be possible on Earth. Ozone prevents harmful ultraviolet radiation from the Sun (light with wavelengths less than 320 nm) reaching the ground. If allowed to reach Earth, this radiation would severly damage the cells that plants and animals are made up of. Ozone was first formed in the Earth's atmosphere after the release of oxygen, between 2000 and 600 million years before the first humans appeared. The Ozone Hole QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Oct 1998 Ozone also plays a very important, natural role in the upper atmosphere (the stratosphere). Ozone absorbs harmful ultraviolet (UV) radiation from the sun. Reductions in ozone results in the increase of harmful UV radiation reaching the Earth's surface. The biggest destroyer of the ozone in the stratosphere is human produced chemical compounds: (chlorofluorocarbons - CFC's), Earth radiance in the near ultraviolet spectrum. More solar UV light is reaching the Earth over polar regions. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. March 14, 2006 Ozone Layer: Damage and Recovery QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. In 1985 over 60 countries pledged to phased out a group of chemicals called CFC's. These very stable chemicals were once widely used in aerosols and refrigerators. It was thought that their release into the atmosphere produced chlorine radicals which reacted with O3 to produce O2. The emission of CFC's into the environment is now greatly reduced. Human Activity Changes Our Planet Ozone “hole” forming in the ozone layer over the Antarctic. CFC (chlorofluorocarbons) Cl-O International Treaties and policies: Montreal protocol: phase out of production of CFC and methyl bromide. Ozone hole will take decades to recover: 100 year lifetimes of CFCs in the atmosphere. Recovery will be slow. Habitat Destruction and Pollution Chemicals, such as pesticides, damage reproduction of many species. Habitat is lost, such as wetlands and migration paths over hundreds of miles. Extinctions occurring at high rates, compared to historic averages. What are Weather and Climate? Weather – short-term changes in wind, clouds, temperature, and pressure in an atmosphere at a given location Climate – long-term average of the weather at a given location These are Earth’s global wind patterns or circulation • local weather systems move along with them • weather moves from W to E at mid-latitudes in N hemisphere Two factors cause these patterns • atmospheric heating • planetary rotation Global Wind Patterns Air heated more at equator • warm air rises at equator; heads for poles • cold air moves towards equator along the surface Two circulation cells are created in each hemisphere Cells of air do not go directly from pole to equator; air circulation is diverted by… Coriolis effect • moving objects veer right on a surface rotating counterclockwise • moving objects veer left on a surface rotating clockwise Global Wind Patterns On Earth, the Coriolis effect breaks each circulation cell into three separate cells • winds move either W to E or E to W • Coriolis effect not strong on Mars & Venus • Mars is too small • Venus rotates too slowly • In thick Venusian atmosphere, the pole-to-equator circulation cells distribute heat efficiently • surface temperature is uniform all over the planet Clouds, Rain and Snow Clouds strongly affect the surface conditions of a planet • they increase its albedo, thus reflecting away more sunlight • they provide rain and snow, which causes erosion Formation of rain and snow: Four Major Factors that affect Long-term Climate Change Gain/Loss Processes of Atmospheric Gas Unlike the Jovian planets, the terrestrials were too small to capture significant gas from the Solar nebula. • what gas they did capture was H & He, and it escaped • present-day atmospheres must have formed at a later time Sources of atmospheric gas: • outgassing – release of gas trapped in interior rock by volcanism • evaporation/sublimation – surface liquids or ices turn to gas when heated • bombardment – micrometeorites, Solar wind particles, or highenergy photons blast atoms/molecules out of surface rock occurs only if the planet has no substantial atmosphere already Gain/Loss Processes of Atmospheric Gas Ways to lose atmospheric gas: • condensation – gas turns into liquids or ices on the surface when cooled • chemical reactions – gas is bound into surface rocks or liquids • stripping – gas is knocked out of the upper atmosphere by Solar wind particles • impacts – a comet/asteroid collision with a planet can blast atmospheric gas into space • thermal escape – lightweight gas molecules are lost to space when they achieve escape velocity gas is lost forever! Origin of the Terrestrial Atmospheres Lack of magnetospheres on Venus & Mars made stripping by the Solar wind significant. • further loss of atmosphere on Mars • dissociation of H2O, H2 thermally escapes on Venus Gas and liquid/ice exchange occurs through condensation and evaporation/sublimation: • on Earth with H2O • on Mars with CO2 Since Mercury & the Moon have no substantial atmosphere, fast particles and high-energy photons reach their surfaces • bombardment creates a rarified exosphere Climate History of Mars • More than 3 billion years ago, Mars must have had a thick CO2 atmosphere and a strong greenhouse effect. • the so-called “warm and wet period” • Eventually CO2 was lost to space. • some gas was lost to impacts • cooling interior meant loss of magnetic field • Solar wind stripping removed gas Greenhouse effect weakened until Mars froze. Rock cycle QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Rock cycle QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Water cycle QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Residence time Average amount of time spent in a reservoir Amount in/time Amount in reservoir Amount out/time Residence time = amount in reservoir/amount added (removed) per unit time Residence time at Berkeley 20,000 students 5,000 enter (leave)/year Residence time? Residence time = 20,000 students/5,000 students/year = 4 years Residence time of water in the ocean Volume in ocean: 1.3x109 km3 Discharge from rivers: 3.5x104 km3/yr Residence time: volume/discharge = 1.3x109 km3/ 3.5x104 km3/yr = 30 x 103 years Carbon cycle QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Long term Carbon cycle QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Carbon cycle: volumes QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Earth’s Magnetosphere Solar Wind: Electrons, protons, helium nuclei