29 terms

Ocean 15


Terms in this set (...)

climate change and the integrity of science
-planet warming due to increased concentrations of heat-trapping gases in atmosphere
-most of the increase in the concentration of these gases over last century is due to human activities, ie burning of fossil fuels and deforestation
-natural causes always play a role in changing Earth's climate, but are now being overwhelmed by human-induced changes
-warming the planet will cause many other climatic patterns to change speeds unprecedented in modern times, including increasing rates of sea-level rise and alterations in the hydrologic cycle. rising concentrations of carbon dioxide are making the oceans more acidic
-the combination of these complex climate changes threatens coastal communities and cities, our food and water supplies, marine and freshwater ecosystems, forests, high mountain environments and more
climate system
exchanges of energy and moisture between:
feedback loops
end results of process modifies inputs
-positive feedback loops - enhance initial change
-negative feedback loops - counteract initial change
past climates are reconstructed and causes of changes are identified through paleoclimatology
proxy data
indirect evidence using natural recorders of climate variability
-sea floor sediments
-coral deposits
-glacial ice rings
-tree rings
-historical documents
the climate can change through natural causes
solar energy changes
variations in Earth's Orbit
volcanic eruptions
movement of earth's plates
Linked to Pleistocene ice Age, Little Ice Age, Medieval Warm Period
Recent change unprecedented
milankovitch theories
eccentricity of Earth's orbit
obliquity of Earth's axis
precession of Earth's axis
solar energy changes
variable energy from the Sun over time
little evidence to link solar activity with climate change
volcanic eruptions
-volcanic ejecta may block
-need many eruptions in short time period
-not observed in recent history
movement of Earth's Plates
-changes ocean circulation
-extremely slow process
-climate change would be very gradual over millions of years
Recent change unprecedented
magnitude and rate of change
more likely result of human activity than natural causes
intergovernmental Panel on Climate Change (IPCC)
published assessments since 1990
predict global temperature changes of 1.4-5.8 degrees C by 2100
climate change models can mimic modern conditions only if human emissions are taken into account
greenhouse effect
incoming radiation from sun: short wavelengths
outgoing radiation from earth: long wavelengths
-net warming effect
rates of energy absorption = rates of reradiation
water vapor
-most important absorber of heat
-66-85% of greenhouse effect
carbon dioxide
-natural part of atmosphere
-greatest relative contribution from human activities
-burning of fossil fuels
-second most abundant human-caused greenhouse gas
-great warming power per molecule
-landfill decomposition
records of global temp show warming
-glaciers and ice caps are melting
-winters are shorter
-species distribution are changing
-global temperature is rising
-sea surface temperature is increasing
-the 8 warmest years have occurred since 1998
-Earth's surface temperature has risen 0.8 degrees C in last 140 years
predicted effects of global climate change
-more days above 90 degrees
-more severe droughts and flooding
-retreat of mountain glaciers
-Reduced water supplies and quality
-Ecosystem changes and extinctions
-Increasing ocean temperatures
-Increased hurricane activity
-changes in deep-water circulation
-Polar Ice Melting
increasing ocean temperatures
-sea surface temperatures rised mostly since 1970
-deep waters showing increases
increased hurricane activity
-warmer water fuels hurricanes
-severity of recent Atlantic hurricanes
-number of global tropical storms have not increased worldwide
-intensity of storms has increased
-more category 4 and 5 hurricanes
-Rising Sea Level
changes in deep-water circulation
-North Atlantic especially sensitive
-melting glaciers
-warmer surface waters
Polar Ice Melting
-arctic amplification
-loss of more than 2 million square kilometers of Arctic sea ice in last decade
-loss of ice = enhanced warming due to lower albedo
-Arctic ice melting affects polar bear survival
-Food sources are dwindling for human Arctic dwellers
-Marine species migration
-Antarctica shrinking, glaciers thinning
The other CO2 prolem
ocean acidity increase
-CO2 dissolves in ocean water
-threatens calcifying organisms
rising sea level
-severely affect areas with gently sloping coastlines
-models predict rise between 0.5 - 1.4 meters by year 2100
changes in the ocean
-sound transmission in ocean
-reduced dissolved oxygen - marine dead zones
-change in ocean productivity
-marine organisms unable to adapt to temperature changes
reducing green house gases?
-human emissions contributing excessive CO2
-global engineering - attempts to counteract human caused climate change
-reducing sunlight reaching earth
-removing human caused greenhouse gases
Ocean's Role in reducing greenhouse gases
ocean's biological pump
-'sink' for carbon dioxide
-pumps from surface to deep waters

ocean as thermal sponge
-unique thermal properties of water
-oceans absorb much heat without changing temperature
-oceans will warming
iron hypothesis
-fertilize ocean to increase productivity
-increase phytoplankton, increase carbon dioxide removal from atmosphere
-sequestering excess carbon dioxide in oceans
Kyoto protocol
international agreement - 60 nations
voluntarily limit greenhouse gases
even if gas emissions stabilize, Earth will continue to warm
human activities are altering the global environment