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Global Ecology

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Global Currents and Terrestrial Biomes Map
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Terrestrial Biomes
Tundra
Boreal Forest, Taiga
Temperate Conifer Forest
Temperate Broadleaf, Mixed Forest
Montane Grassland, Shrubland
Temperate Grassland, Savanna, Shrubland
Mediterranean Forest, Woodland and Scrub
Desert, Xeric Shrubland
Tropical, Subtropical Dry Broadleaf Forest
Tropical, Subtropical Grassland, Savanna, Shrubland
Tropical, Subtropical Coniferous Forest
Tropical, Subtropical Moist Broadleaf Forest
Flooded Grassland, Savanna
Mangrove
Snow, Ice, Glacier, Rock
Thermohaline Currents
Surface
Deep
Bottom
Phytoplankton Density
High Low
Driven by temperature and salinity gradients, the thermohaline current (THC) travels a 1,000 year circuit bringing cold water and nutrients up from the deep ocean and moving warmer water from the tropics toward the poles. Part of the earth's ocean circulatory system, this huge current moderates the potential extremes of climate, temperature and rainfall.

Ocean currents cause the nutrient rich cold bottom waters to upwell to the surface, providing a regularly renewed food source for phytoplankton - the foundation of the marine food chain on which other marine organisms depend. Algae capture more of the sun's energy in photosynthesis and produce more oxygen than all other plants combined.1
Thermohaline Change Evidence is growing that the thermohaline current may be slowed or stopped by cold fresh water inputs to the Arctic and North Atlantic oceans. This could occur if global warming is sufficient to cause large scale melting of arctic sea ice and the Greenland ice sheet. Such a change in the current may be gradual (over centuries) or very rapid (over a few years). Either would cause planet wide changes in climate. This effect may be part of what starts and stops the ice ages. The land in the northern hemisphere has been unfrozen for less than half of the last 400,000 years (see ice ages). In 2005, it was discovered that deep water formation under the Arctic "Odden ice tongue" had almost stopped.3   (See Arctic map.)

"Diatoms (a kind of phytoplankton) are estimated to "scrub" roughly as much CO2 from the atmosphere each year as all the world's rainforests. In coastal environments they account for as much as 90% of the organic matter generated through photosynthesis." 1

"Net primary productivity is the mass of plant material produced each year on land and in the oceans by photosynthesis using energy from sunlight. Net primary productivity is the total food resource on the earth." 2

The Arctic and Antarctic


Click to
      open a larger version in a new window Sea ice and glaciers are melting all over the globe from warmer temperatures. Over 60% of the world's fresh water is stored in the ice sheets covering Antarctica - up to 4.5 km thick and up to 25 million years old. The Ross ice shelf alone is as large as France. The average temperature on the Antarctic Peninsula has risen 4.5F since 1947. All of the major floating ice shelves are shrinking - melting more during the summer than is being refrozen during winter - about 8,000 sq. km have been lost since the 1950s.1 Were the West Antarctic ice sheet to melt due to climate warming, it could raise sea levels by 20 ft 2. Sea levels are already rising by 2mm a year - faster than during the past 5,000 years.3 Krill - small shrimplike sea creatures that are a major food source for seals, whales and penguins - feed on algae found on sea ice. In Antarctica, they are concentrated northeast of the Antarctic Peninsula - but have declined 80% since the 1970s.4
Click to open a larger version in a new window Industrial air pollution from the developed world is carried on the dominant wind currents up to the arctic. After settling onto the tundra, snow and ice it is absorbed into the food chain. The people and creatures there have some of the highest concentrations of toxins in their bodies of anywhere on earth.



Climate Change


Scientific evidence and peer reviewed consensus affirm that climate change and global warming are happening. The most potent research to date indicates that the extent and direction - warming or cooling - of climate change could be much greater and faster than previously predicted. 1
CO2 concentrations are already well above historic maximums. The GWP (Global Warming Potential) of methane gas (CH4) is 21 times greater than the GWP of CO2. Warming could release vast quantities of methane from thawing tundra and sea bed methane hydrates.2








Main Human Activites Causing Destructive Effects on Ecosystems
Population and consumption growth Infrastructure development (dams, urban growth, highways) Land conversion (deforestation, agriculture, urban growth) Overharvesting / overexploitation (overfishing, wasteful irrigation) Release of pollutants (human waste, agricultural / industrial chemicals, radioactivity) Introduction of exotic species (replacing and overwhelming indigenous species). 5


Biodiversity

Biodiversity is the variety of life found at all levels of biological organization, ranging from individuals and populations to species, communities and ecosystems. A population is a group of individuals of the same species in a given location - a group that is genetically different from other such groups. Species are made up of one or more populations. There were an estimated 2.2 billion populations on Earth. populations are going extinct at a rate of 32,000 per day. The loss of populations is occurring three to eight times faster than species loss. If all of a species' populations but one are destroyed the species technically still exists. However, all of the beneficial interrelations flowing from those populations and their biodiversity will have been lost.


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Deforestation and Habitat Loss
"Conversion of forest or grasslands into croplands results in the local extinction of plant and animal species..."3

"The health of land and water - and of woods, which are the keepers of water - can be the only lasting basis for any civilization's survival and success." 4



Solar Energy
Some of the sun's energy is being blocked from reaching the earth by air pollution. Because the dirty air reflects light away from the earth before it reaches the ground, it has significantly reduced the reception of solar energy - calculations of the effect (from 4% to 30%) vary from region to region. As this type of air pollution is reduced, the amount of energy absorbed by the earth will increase - possibly contributing dramatically to global warming and climate change.


Ozone
Ozone gas in the upper atmosphere filters out the sun's ultraviolet rays and protects life forms from overexposure. This layer has been polluted by human activities and has developed thin areas or "holes" which let in more damaging levels of UV radiation. This in turn adversely affects many life forms - plants, animals and humans. Even after the various chemicals causing this effect are no longer being released, it will be decades or centuries before their disruptive effects disappear.


Space Debris
  • As of april, 2005 at least 13 nuclear reactor fuel cores, 8 thermoelectric generators, and 32 nuclear reactors are known to be in Earth orbits below 1700 km.

  • Low Earth orbit ~ 250-600 km from earth - International space station

  • Geosynchronous stationary orbit ~ 35,785 km from earth - communications satellites

  • ~ 20,000 km from earth - Global Positioning System (GPS) satellites

  • Before 1961, the entire Earth satellite population was just over 50 objects. Now earth orbit is cluttered with: ~11,000 objects bigger than 10 cm, of which ~9,000 are catalogued and tracked (~8000 are of US or USSR origin) - including around 600 functional spacecraft; ~100,000 objects from 1-10 cm -- too small to track, dangerous to spacecraft; and several million objects smaller than 1cm.

    What are they? Jettisoned mission junk, rocket fuel, space station garbage, abandoned rocket parts, used nuclear reactors, leaked radioactive coolant and exploded bits (~150 unplanned explosions of rockets and satellites have occured to date). Collisions between orbiting debris make even more debris. Hundreds of close passes (less than 1 km apart) occur daily between catalogued objects. Each year around 100 objects fall out of orbit and survive re-entry, crash landing somewhere on earth. Dozens of earth orbit satellites launched by the USSR and the USA between 1965-1988 used nuclear power. Several have fallen out of orbit and crash landed. Nuclear power systems are being considered for projects in the next decade. About 75 - 100 new satellites are launched each year.


    Sources


    Oceans and Terrestrial Biomes Map Sources:
    World Wildlife Fund Terrestrial Ecoregions, www.wwf.org
    ESRI, http://www.esri.com/
    Goddard Space Flight Center SeaWIFS data, www.gsfc.nasa.gov/topstory/20020801plankton.html,
    Gaia, An Atlas of Planet Management,
    http://www.globalchange.umich.edu/globalchange2/current/lectures/fisheries/fisheries.html

    Ecosystem and Biodiversity Text Sources:
    1. Christian Science Monitor, "Tiniest Creatures in the World Reveal Health of Oceans", Dec. 16, 2004
    2. Environmental Researc h Foundation, www.ejnet.org/rachel/rhwn256.htm
    3. UNEP: Global Environment Oulook 3, http://www.unep.org/geo/geo3/
    4. A Short History of Progress, Ronald Wright, House of Anansi, 2004
    5. "Threats to Global Biodiversity", http://www.globalchange.umich.edu/globalchange2/current/lectures/biodiversity/biodiversity.html

    http://news-service.stanford.edu/news/1997/october29/population.html;
    What We Must Do to Counter the Biotic Holocaust, Myers, www.nwf.org/internationalwildlife/1998/holocaus.html

    Antarctica Map Sources:
    "Antarctic Region"; Perry Castaneda Map Library, www.lib.utexas.edu/maps/; National Snow and Ice Data Center, http://nsidc.org; National Geographic Maps, "Antarctica",Feb. 2002
    Sea Ice and Glaciers Text:
    1. British Antarctic Survey, www.antarctica.ac.uk/Key_Topics/IceSheet_SeaLevel/ice_shelf_loss.html
    2. Antarctic and Southern Ocean Coalition, "Ice Shelves", www.asoc.org/general/iceshelve.htm
    3. British Antarctic Survey, www.antarctica.ac.uk/Key_Topics/IceSheet_SeaLevel/index.html
    4. British Antarctic Survey, www.antarctica.ac.uk/News_and_Information/Press_Releases/

    Industrial Air Pollution Source:
    "Impacts of a Warming Arctic", Arctic Climate Impact Assessment, Cambridge University Press, 2004, www.acia.uaf.edu;
    Dominant Air Currents, Ocean Currents:
    UNEP GRID-Arendal, www.grida.no

    Climate Change Graphs:
    WRI Earthtrends Database, http:/earthtrends.wri.org;
    Keeling, Whorf, C02 Research Group, Scripps Inst.of Oceanography, http://cdiac.ornl.gov/ftp/ndp001/maunaloa.co2;
    Vostok Ice Core Data for 420,000 Years, IGBP PAGES/World Data Center for Paleoclimatology, Series #2001-076;
    NOAA/NGDC Paleoclimatology Program, www.ngdc.noaa.gov/paleo/icgate.html;
    The Intergovernmental Panel on Climate Change (IPCC), "Climate Change 2001", www.grida.no/climate/ipcc_tar/wg1/221.htm;
    Wikipedia, wikipedia.org/wiki/Ice_age;
    UNEP GRID Arendal, www.grida.no/db/maps/collection/climate5/2100.htm

    Climate Change Text:
    1. "Uncertainty in Predictions of the Climate Response to Rising Levels of Greenhouse Gases", www.climateprediction.net/science/pubs/nature_first_results.pdf
    2. Almanac of Policy Issues, US EPA Documents, "Climate Change", www.policyalmanac.org/environment/archive/climate_change.shtml
    3. www.truthout.org/issues_05/051005EA.shtml,
    4. http://www.usna.edu/Oceanography/courses/SO426_maksym/

    Solar Energy Text:
    Global Dimming, http://news.bbc.co.uk/2/hi/science/nature/4171591.stm; en.wikipedia.org/wiki/Global_dimming

    Space Debris:
    Image: NASA
    Text: UN Office for Outer Space Affairs: www.oosa.unvienna.org/
    www.orbitaldebris.jsc.nasa.gov/index.html