Lecture 13: More Climate Controls & Measuring Climate

Comprehensive vocabulary flashcards covering the Earth's climate spheres (hydrosphere, biosphere, cryosphere, lithosphere) and paleoclimate measurement techniques, including ice cores and proxy methods.

Hydrosphere

The system comprising all of Earth's water, especially the oceans, which helps regulate global climate due to water's high heat capacity.

Heat capacity (of water)

The physical property that allows water to absorb a large amount of heat without changing temperature very quickly.

Gulf Stream

An ocean current that carries warm water from the Gulf of Mexico along the eastern United States toward the North Atlantic, redistributing heat.

Thermohaline circulation

The large-scale movement of ocean water driven by differences in temperature ('thermo') and salinity ('haline'), where cold, salty, dense water sinks.

Biosphere

The global ecological system comprising all living organisms, which affects climate by altering atmospheric greenhouse gas levels such as $CO_2$ and methane.

Biological pump

The process by which carbon is transported from the ocean surface into deeper ocean water and ocean sediments through biological activity.

Phytoplankton

Tiny ocean plants living near the water surface that absorb $CO_2$ from the atmosphere through photosynthesis.

Marine snow

Sinking biological debris, such as dead marine organisms and waste products, that carries carbon from the ocean surface to the deep sea.

Cryosphere

The sphere consisting of all of Earth's frozen water, including glaciers, snow cover, and ice sheets.

Albedo

A measurement of the proportion of incoming solar radiation reflected by a surface; snow and ice exhibit high albedo, whereas typical land surfaces have lower albedo.

Lithosphere

Earth's solid outer rocky layer, which influences climate via continental position, continental size, mountain building, and the formation of land bridges.

Rain shadow

A dry area formed on the leeward side of a mountain after moist air is forced upward, cools, and precipitates on the windward side before descending as warm, dry air.

Land bridge

A terrestrial connection created by tectonics or sea-level changes that can redirect or block ocean circulation between ocean basins.

Ice core

A long cylinder of ice drilled from ice sheets or glaciers containing trapped air bubbles, which provide actual direct samples of ancient atmospheric composition rather than a proxy.

Climate proxy

An indirect natural recorder or measurement used to estimate past environmental and climatic conditions before modern instrumental records existed.

Tree-ring width

A paleoclimate proxy where the thickness of annual growth rings indicates past growing conditions, with wider rings reflecting more favorable conditions.

Biogeography (as a climate proxy)

The study of the geographic distribution of organisms (such as crocodilians) used to infer past climate based on the specific environmental tolerances of those species.

Magnesium/calcium ($Mg/Ca$) ratios

A chemical proxy measured in fossil shells that provides quantitative (numerical) temperature estimates based on temperature-dependent elemental incorporation.

Isotopes

Atoms of the same chemical element that possess the same number of protons but different numbers of neutrons, resulting in different masses.

Oxygen isotope ratio ($^{18}\text{O}/^{16}\text{O}$)

A quantitative paleoclimate proxy measured in fossil materials such as shells and fish bones to calculate numerical temperature estimates of past environments.

Carbon isotope ratio ($^{13}\text{C}/^{12}\text{C}$)

A paleoclimate proxy measured in fossil skeletons that reconstructs past vegetation ($C_3$ and $C_4$ plants) and environmental conditions rather than providing direct numerical temperatures.