GCC – The Central Issue • Global Climate change refers to a set of environmental concerns that are related to human activity, primarily • Global warming • The “Ozone Hole”
Global Warming • Global warming refers to the gradual increase of the Earth’s temperature because of energy trapped by the Earth’s atmosphere • The retention of the heat by the atmosphere is called the greenhouse effect.
How the Greenhouse effect works • Heat, in the form of short wave infrared radiation is received by the Earth from the sun • This heat is reflected back out into space in the form of long-wave infrared radiation. • As long as this energy input-output exchange is in equilibrium, we stay the same temperature (globally) • If something alters it, we either heat up or cool down. • (Greenhouses do not work this way)
Scientific Controversy over the greenhouse effect • There is none. • This is accepted by the scientific community as clearly sound. It is not theory, it is part of the scientific ‘canon’ • There is, however, concern that the use of the the term is inappropriate • Bad Science - Greenhouse
Permanentgases • Permanentgases in the atmosphere by percent are: • Nitrogen 78.1% • Oxygen 20.9% • (Note that these two permanent gases together comprise 99% of the atmosphere) • Other permanent gases: • Argon 0.9% • Neon 0.002% • Helium 0.0005% • Krypton 0.0001% • Hydrogen 0.00005%
Variable gases in the atmosphere • Variable gases in the atmosphere and typical percentage values are: • Water vapor 0 to 4% • Carbon Dioxide 0.035% • Methane 0.0002% • Ozone 0.000004% • CFC’s (not naturally occurring)
Greenhouse Gases • Several gases act as heat sinks in the atmosphere • CO2 • CFCs • Methane • Water vapor
Relative concerns over Greenhouse gases • CO2 is the largest concern, being the largest constituent of the atmosphere • Methane holds more heat, but because it is chemically more active, its atmospheric duration is about 10 years • CFC’s hold much more heat, and last a very long time, but still are a smaller portion • Also being reduced due to Montreal protocol
Atmospheric CO2 • Atmospheric CO2 is believed to have been about 280 ppm (parts per million) in the pre-industrial age. • This figure is based on estimates of carbon sinks and flux, along with the geological record. (ice core samples, bubbles in amber, etc)
CO2 • The most plentiful greenhouse gas • Results from • Combustion of fossil fuels • Gas best fuel • Oil medium • Coal worst • Based on ratio of carbon to hydrogen in the molecules • Burning of vegetation/deforestation • Reduced uptake in plants/deforestation
Mauna Loa CO2 observations • The data on atmospheric CO2 collected by Keeling at the Mauna Loa observatory is said to be the most widely seen data set in the world. • It was started in 1955 • CO2 was at 313ppm then • It is at 375ppm now (2002), an increase of 16.5% in 47 years
The Keeling Data • If you wish to play with the data… • CO2 data - txt • CO2 data - Excel • CO2 data – STATA • Source: • http://cdiac.esd.ornl.gov/trends/co2/sio-mlo.htm
Carbon Sources and Sinks • Places that provide carbonare called reservoirs. • Places where carbon settles are called sinks • Exchanges between sinks and reservoirs are called fluxes. • There are four major reservoirs for carbon • The atmosphere • The oceans • The biosphere • Fossil fuels • Ultimately the crust forms the basic sink for carbon via the deep oceans to carbonate rock and fossil fuels
Sources • “Sinks for Anthropogenic Carbon”. Physics Today • The Role of Land Carbon Sinks in Mitigating Global Climate Change • http://www.royalsoc.ac.uk/files/statfiles/document-150.pdf
Methane • Sources • Coal mining • Oil production • Organic decomposition • Animal digestion • Resident in atmosphere about 10 years
CFCs • Nasty little gases – only anthropogenic • CFCs do not occur in nature – the Fluorine bond is to strong to break naturally. • CFCs come from • Refrigerants • Styrofoam, foaming agents • Cleaning electronics • Spray propellants
Impacts of Climate Change • Temperature rise • Precipitation • Soil Moisture • Changing Habitats • Sea Level Rise • Ocean Currents
Temperature Rise • Estimates are in the 1.5° to 4.5° C range based on General Circulation Models (GCM) of the atmosphere. • Every degree C is equal to about 100 miles of latitude. • This means that WV will have the ecosystems of North GA/SC • Rising temperature means rising AC usage, which means rising CO2 consumption, accelerating greenhouse effect • This is a positive feedback loop
Feedback loops • Positive • The change increases the process driving the change • Polar ice pack melt • As the sea ice gets thinner due to warming, the heat exchange between warm sea water below the ice and cold air above the ice speeds up, leading to faster melting of the ice. • The last 25 Years – NASDA Video • Negative • The change produces an offsetting or equilibrating process • As temperature rises, evaporation increases, leading to increased cloud formation, increasing albedo, thereby lowering temperature
Icebergs • Glacier flow • Melting provides lubrication • Increases snow itself can cause compression – resulting in faster flow. (A worry if winters are warmer, but snowy due to increased water vapor) • They are increasingly of concern • National Naval Ice Center • Ice Berg battering ram
Weather • Climate change is not a problem of a few degrees, it is one of change in • weather patterns • Precipitation changes • climatic subsystems • Ecosystem change • Coral reefs • Bleaching
Changes in Precipitation • Changing Patterns of rainfall/drought • Extreme Precipitation events • Droughts • Storms - flooding • Snowfall • Hurricanes • In a warmer world, more hurricanes, longer season, and more powerful storms
Soil Moisture • Increased temperature means a decreased spoil moisture unless precipitation increases • Western wildfires
Changing Habitats • Changes in habitat • Migration patterns • Ecosystem changes • Changes in species populations can ripple through an ecosystem.
Ocean Fisheries • Pacific Salmon declining precipitously • Anchovy harvest in SA • Responsive to el Nino events • Pacific Tuna
Sea Level Rise • Thermal expansion of water • Arctic Ice pack • Glaciers • Greenland • Western Antarctic
Thermal Expansion of Water • Water molecules get larger as they get warmer. • Sea level rises about 1cm per .1° C • Hence sea level has risen about 10cm since 1900, along with a global mean sea level temp rise of about 1° • Thus sea level may rise by 15-45cm due to thermal expansion
Artic Ice Pack • Adds 0 to sea level rise • Ice floats, and displaces its weight, hence volume will remain constant
Glaciers • Almost all glaciers have receded in last century • Possible that increased precipitation may cause increased glaciations on South pole • Examples of Glacier recession
Western Antarctica • The Western Ice packs in Antarctica hold vast quantities of water. • Increased snowfall may actually accelerate glaciation • Sea Level rise of 21 feet (7 meters) possible in the next century
The scary stuff • Loss of both Antacrcic and Greenland glaciers • Sea level rise of ~75’ • Global Dimming • Accelerating warming very quickly • Ocean current disruption
Ocean Currents • Ocean currents are subject to changes in temperature and salinity • Record indicates changes in: • Gulf stream • Alaska Gyre • California Current off central North America
Human Impacts & Security Issues • Disease • Malaria • West Nile • Dengue Fever • Ebola ? • Insects
More Issues • Food security • Immigration patterns • Storms & disasters • Bangladesh – 1970
The Montreal protocol • Due to the Montreal protocol, CFCs will be less of a concern, as time goes on • Outlawed manufacture, sale or use of CFCs in many instances
Why was Montreal successful? • The Montreal Protocol occurred because: • Scientific agreement on problem (upper atmospheric CFC’s destroy upper atmospheric ozone (O3++). • Technological substitutions are economically viable. • The company which held the license on the offending chemicals (Freon 11,12, etc) also held newer licenses on those substitutes (DuPont).
Will Montreal occur for climate change? • No! • Scientific consensus will not emerge until it is too late • The winners and losers have very large stakes. • Technological substitutes are not available, or will be economically prohibitive.
The Tragedy of the Commons • Global Climate Change is the Tragedy of the Commons at its most global expression • N –’person’ • Not to any nations advantage to unilateraly reduce emissions
Policy Options • Sequestration • Practical to sequester power plant CO2? • Look at the weight • Biological means • Terrestial
Carbon Tax • Price dictates consumption • And little else does!