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Course definition • Can’t understand planetary processes including oceanography without understanding the planet – Planet includes: atmosphere, geosphere, hydrosphere, biosphere – Each component has its sub-discipline but all feedback upon each other – Why oceanography? The ocean plays a huge part in all components – climate, biodiversity, heat balance, etc. – We start with the big bang and end with the future • Need to understand relationships and feedbacks to understand past, present and future conditions System • Interconnectedness of components – Can’t understand one part without the other – Can’t predict one part without considering the others • System – a functional unit composed of interconnected parts (components) – Scales – micro to mega, depends on your definition – Biological systems easiest to visualize and on the right timescales – human body; ecosystems, etc – Ecosystem collapse The Earth System • Mass and energy balance – on earth mass essentially closed, energy is not – Other budgets – examples, your garden, your body? • System – entity composed of interconnected parts (components) – Biological systems – human body; ecosystems, etc • The Earth System – Comprised of components where mass, material or energy exchange can be opened or closed Four components in the Earth System: solid earth, water, gas, biota The Earth Sub-systems • • • • • What are they? What are the major reservoirs? Where are there exchanges? What are the exchanges? Mass, energy? Are the fluxes between compartments equal? Will they stay equal? What is equilibrium? • What are the turnover times? • Where are the interactions between systems? Interactions • Self-regulation • Feedbacks loops – how does earth stay habitable – Positive feedbacks – Negative feedbacks Reductionist Approach • State the problem • Find a reason – At what point in time – At what physiological state – Under what physical and chemical conditions Systems Approach • • • • Relationships Synthesis Evolution of interactions How interactions change under different scenarios • Self-regulation – Positive feedbacks – Negative feedbacks Earth’s organization • Highly organized – why? • Self-organization – Energy cycling – Feedbacks among system components Climate change • Greenhouse effect – radiative effect – Climate observations (Keeling curve – atm. CO2 on Mauna Loa, Hawaii – 1958-present) – Independent data sets – ice cores, etc – Time scales, rates of change • Greenhouse gases – Many and diverse (H2O, CO2, CH4, N2O and aerosols) – Some completely anthropogenic (freons [CFCs]) – Anthropogenic emissions by country – industrial vs. land use changes – Rate of change of production • C cycling The Greenhouse Effect • Necessary for life on earth – and its natural • Controls the earth’s climate • Greenhouse gases absorb outgoing IR radiation What is unnatural or due to humans (anthropogenic) Impact on Global Surface Temperature 0 400,000 Years before present Vostok ice core records Glacial pCO2 minima ~180 ppm change of about 100 ppm over 100,000 years 0.001 ppm/year Change of ~80 ppm 0.4 ppm/year What is unnatural or due to humans (anthropogenic) Use of fossil fuels Deforestation 750 – 800 ppm 2100 Rising atmospheric pCO2 Ozone depletion • Political success • Tractable by eliminating a few chemicals (CFCs) Atmosphere & Ocean • Gases and water freely exchange at the oceanatmosphere interface • Movement of air (and water) by wind help minimize worldwide temperature extremes. • Weather is influenced by the movement of water in air (state of the atmosphere at a specific time and place) • Climate is the long-term average of the weather in an area • Interaction between atmosphere and hydrosphere Composition of the atmosphere • 78% nitrogen and 21% oxygen • Other elements make up < 1% • Air is never completely dry and water can be up to 4% of its volume. • Residence time of water vapor in the atmosphere is ~10 days. • Interaction with water cycle/hydrosphere Atmospheric circulation • Powered by sunlight • About 51% of incoming energy is absorbed by Earth’s land and water • Light penetration varies depending on the angle of approach, the sea state and the presence of ice or other covering (e.g., foam) • Affects planetary heat balance Heat budget • Energy imbalance – more energy comes in at the equator than at the poles • 51% of the short-wave radiation (light) striking land is converted to longer-wave radiation (heat) and transferred into the atmosphere by conduction, radiation and evaporation. • Eventually, atmosphere, land and ocean radiate heat back to space as long-wave radiation (heat) • Input and outflow of heat comprise the earth’s heat budget • We assume thermal equilibrium (Earth is not getting warmer or cooler) or the overall heat budget of the earth is balanced Incoming radiation • 16% of incoming solar radiation absorbed by dust • 3% absorbed by clouds • 51% absorbed by earth • 6% backscattered by air (leaves atm) • 20% reflected by clouds (leaves atm) • 4% reflected by earth’s surface (leaves atm) Outgoing radiation • • • • 38% emission by water and CO2 (leaves atm) 26% emission by clouds (leaves atm) 6% surface emission 30% that was reflected or scattered Of that absorbed by earth • 21% radiated – 15% is absorbed by water and CO2 (greenhouse effect) – 6% leaves the atmosphere • 7% conductive transfer from ground to air • 23% evaporation Earth’s heat budget and sun • Earth is a closed system (essentially) wrt mass but not energy • Solar luminosity changes (increases over time due to nuclear reactions within the sun) • Greenhouse gases alter heat loss from planet Inputs Exports Concentration Pool Size Maintained Inputs Exports Concentration Accumulates Inputs Exports Concentration Declines Fluxes through reservoirs – relative sizes and residence time is important Simplified C cycle Sources and sinks • • • • • Fossil fuel burning Industry & auto Other Biomass burning Climate feedbacks • Terrestrial C sinks – Agriculture – Forestry • Oceanic C sinks – Sinking C – Burying C • Atmospheric reactions *Think about time scales of processes Estimated size of C reservoirs (Billions of metric tons) • Atmosphere • Soil organic matter • Ocean • Marine sediments & sedimentary rocks • Terrestrial plants • Fossil fuel deposits • 578 (as of 1700) to 766 (in 1999) • 1500 to 1600 • 38,000 to 40,000 • 66,000,000 to 100,000,000 • 540 to 610 • 4000 Controls of CO2 in the ocean • Carbonate equilibria/speciation – Carbonate precipitation/dissolution • Global circulation – Solar heating and upwelling of CO2-rich water • Photosynthesis and biosynthesis of carbonate 6CO2(g) + 6H2O hv C6H12O6 + 6O2 (g) • Oxidation of organic matter • Bacterial respiration Important Concepts affecting the ocean C cycle • • • • Temperature and gas solubility Temperature and biology Physical stratification New production vs. recycled or regenerated production • Biological Pump Projections and uncertainties • Biota – geographical ranges and timing of spring blooms • Water cycle • Ocean circulation • Global heat budget • Clouds • Ocean ventilation • Sea level rise – ice and thermal expansion Global change on long timescales Timescales of disturbances • Mass extinctions – K-T – Permian-Triassic • Mass extinctions – Reradiation – Past and future can look very different (mesozoic mammals) • Evolution – natural selection and biodiversity • Adaptation versus evolution • Rates of change within a disturbance important – Sealevel rise and wetlands Dinosaurs - popular Mass extinction events “recycling” of crustal and oceanic materials “uni-directional” change of the crust and oceans Less known but massive Origin of the Earth • How old is earth and why should we believe it (dating of a variety of things) • Geological history – Hadean and Archean… 0 400,000 Years before present Vostok ice core records Glacial pCO2 minima ~180 ppm K-T Boundary • Rare earth element Iridium spike • Meteorite • 65 million years ago • Fossil record Permian-Triassic Mass Extinction • • • • • • • Circa 251 million years before present 85% of terrestrial species extinct 95% of marine species extinct Related to CO2 Volcanic eruptions of greenhouse gases Acid rain, thinning ozone, and warming Slow circulation, stagnation, low oxygen, hydrogen sulfide production Gaia • Earth as an “organism” • Life responds to physical forcing with counteracting forces that stabilize the planet • Earth is alive People equal C and N People = Nutrients • Quite literally: 14 kg N (31 lbs) and 1.1 kg P (2.4 lbs) per person per year • 128 gals of sewage per person per day • 2.5 kg of garbage per person per day • Atmospheric N = 10-40% of N load, VMT increasing at 4 times population A Nighttime View of the Earth -distribution of people and land OVERVIEW • Public policy process has become increasingly important to academic research. • Science and Engineering community have not been involved with the public policy process in proportion to its importance to the community. • Interactions between science and policy realms serve both, but require knowledge of each other’s processes. • Interactions can take as much or as little time as scientists are willing to undertake THE CHALLENGE Scientific advance is a necessary but not sufficient condition for social progress Science must be mediated through other social institutions (social, economic, and political) before social progress can occur. The gap between the “Two Cultures” must be bridged • C.P. Snow’s 1959 Reade Lecture alleged that social progress was hindered by the communications gap between science and the humanities RELATIONSHIP BETWEEN PUBLIC AWARENESS AND POLITICAL ACTION OVER TIME Public Awareness Political Action Political Interest Public Interest Media Interest Advocacy Group Interest Scientific Interest Time CLIMATE CHANGE NUCLEAR CONFLICT Globe International Treaty OVER FISHING/ COLLAPSE State Law Nation State/Province Scale of Impact National Law Mode of Remedy Region ACID RAIN – LAKE EFFECTS AUTOMOBILE AIR POLLUTION CHERNOBYL Local Ordinance Community BOPHAL ACCIDENT Individual/ OCCUPATIONAL CANCER Group Action Individual Time of Impact Day ENVIRONMENTAL EVENTS: SCALE, TIME, AND REMEDY Acute Week Month Year Effect Congressional Term(s) Presidential Term(s) Decade Century Chronic