Evidence of Climate Change

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Ice Core Noun

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[ice kor]

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Ice Core

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A cylinder of ice drilled from a glacier, containing a record of past atmospheric conditions and climate history.

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Example: This diagram shows how layers of snow are compressed over thousands of years into dense ice, trapping air bubbles that contain ancient atmospheric gases.

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Isotopes Noun

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[ai-suh-towps]

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Isotopes

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Variants of a chemical element with different numbers of neutrons, used as proxies for past climate temperatures.

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Example: This diagram shows three types of carbon atoms: Carbon-12, Carbon-13, and Carbon-14. They are isotopes because they have the same number of protons but different numbers of neutrons.

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Interglacial Noun

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[in-ter-glay-shul]

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Interglacial

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A brief, warm geological period that separates longer, colder glacial periods within a larger ice age cycle.

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Example: This graph shows that an interglacial is a naturally occurring warm period that happens between colder glacial periods, or ice ages, over Earth's history.

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Paleoclimate Noun

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[pay-lee-oh-kly-mit]

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Paleoclimate

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The study of climates of the past, reconstructed using evidence from natural sources like ice cores and tree rings.

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Example: This image compares past and present Northern Hemisphere ice coverage, showing how scientists use evidence like ice sheets to study paleoclimates (climates of the past).

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Climate Proxy Noun

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[kly-mit prok-see]

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Climate Proxy

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Preserved physical characteristics of the past that substitute for direct meteorological measurements to reconstruct past climate conditions.

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Example: This graph uses climate proxies, like tree rings, to show Earth's temperature over 2,000 years, revealing a sharp increase in recent times.

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Varves Noun

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[varvz]

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Varves

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Annual layers of sediment found in some lakes, used as a climate proxy to study regional climate changes.

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Example: This microphotograph shows varves, which are annual layers of sediment. The distinct light and dark bands correspond to different seasons, creating a yearly record.

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Palmer Drought Severity Index (PDSI) Noun

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[pahl-mer drowt suh-ver-i-tee in-deks]

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Palmer Drought Severity Index (PDSI)

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A standardized index that measures ground dryness based on recent precipitation and temperature, indicating wet or dry periods.

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Example: This map uses the Palmer Drought Severity Index (PDSI) to show drought. Red and orange areas are drier than normal, while blue areas are wetter.

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Sea Surface Temperature (SST) Noun

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[see sur-fis tem-per-uh-cher]

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Sea Surface Temperature (SST)

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The water temperature at the ocean's surface, which is a key indicator used in climate and oceanographic studies.

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Example: This world map uses a color scale to show sea surface temperature, with red areas being warmest (near the equator) and blue areas being coldest.

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δ¹⁸O (Delta-O-18) Noun

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[del-tuh oh ey-teen]

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δ¹⁸O (Delta-O-18)

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A measure of the ratio of heavy oxygen-18 to lighter oxygen-16, used as a temperature proxy in materials.

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Example: As water evaporates from the ocean and moves inland as clouds, the heavier oxygen-18 isotope rains out first, making later rain and snow isotopically 'lighter'.

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Anomaly Noun

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[uh-nom-uh-lee]

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Anomaly

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In climate science, a deviation from a long-term average or standard value, such as a temperature or isotope anomaly.

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Example: This graph shows the temperature anomaly, or how much the Earth's temperature has differed from the long-term average (the 0.0 line), demonstrating a clear warming trend.