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GEOL 1302 UH (Chapter 8)

Terms in this set (25)

"Hockey stick" model
the combined records from proxy climate data and instrument-based sources from a dozen Northern Hemisphere temperature records covering the past 1000 years.
Faint Young Sun Paradox
4 billion years ago, liquid water flowed on a warmer Earth when the fainter Sun, which produced only 70% of today's energy output
Sunspot
a dark blotch of irregular shape on the face of the Sun, typically thousands of kilometers across, that develops where an intense magnetic field suppresses the flow of gases, transporting heat from the Sun's interior
Maunder minimum
during the 70-year period from 1645 to 1715 sunspot activity declined by a factor of 10 to 20 from its usual value during normal sunspot cycles, and decreased global temperatures
Spörer minimum
a 90-year period of reduced sunspot number from 1460 to 1550 and lower global temperatures
Dalton minimum
a 40-year period of reduced sunspot number from 1790 to 1830 and lower global temperatures
Ice Age
periods of time when extensive ice sheets existed in Northern and Southern hemispheres, linked to anomalously colder surface and atmospheric temperatures
Interglacial
periods between Ice Ages
Orbital parameters
the eccentricity of Earth's orbit about the Sun, Earth's tilt of the rotational axis and precession of the axis
Milankovitch cycles
regular variations in the precession and tilt of Earth's rotational axis and the eccentricity of its orbit about the Sun
Perihelion
shift in the precession cycle of Earth
about the Sun when Earth is closest to the Sun
Aphelion
shift in the precession cycle of Earth about the Sun when Earth is farthest from the Sun
Feedbacks
in climate studies, processes in which a natural or anthropogenic driver affects the climate system by a certain amount, as measured by a specified quantity, which, in turn, changes the first quantity
Positive feedback
in climate studies, when a change in one segment of a sub-system causes a change in climate and that initial change enhances additional changes in climate; an amplifying feedback
Negative feedback
a feedback that dampens an initial change in the climate system; a stabilizing feedback
Ice-albedo feedback
a feedback mechanism that accelerates melting of sea ice and amplify warming
Thermokarst lake
a depression in the ground formed when warming causes melting of ice-rich permafrost and water drains into the depression
Permafrost
Ground that is permanently frozen
Methanogenesis
process by which microbes are able to remain active at extremely low temperatures and produce methane
Methane hydrate
a clathrate, an ice-like solid formed from methane (CH4) and water
Callendar effect
the theory that global climate change can be brought about by enhancement of Earth's natural greenhouse effect by increased levels of atmospheric CO2 from anthropogenic sources, principally the burning of fossil fuels
Keeling curve
record of atmospheric carbon dioxide from NOAA's Mauna Loa Observatory in Hawaii that shows a sustained increase in average annual atmospheric carbon dioxide concentration from about 316 ppm (parts per million) in 1959 to about 400 ppm in 2014
Aerosols
tiny, nanometer to micrometer in size, solid and liquid particles suspended in the atmosphere that vary in size, shape and chemical composition
Sulfurous aerosols
tiny droplets of sulfuric acid and sulfate particles in the air
Black carbon
aerosols that enter the atmosphere as soot
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