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Ice core
An ice core is a core sample from the accumulation of snow and ice over many years that have recrystallized and have trapped air bubbles from previous time periods. The composition of these ice cores, especially the presence of hydrogen and oxygen isotopes, provides a picture of the climate at the time.
Because water molecules containing heavier isotopes exhibit a lower vapor pressure, when the temperature falls, the heavier water molecules will condense faster than the normal water molecules. The relative concentrations of the heavier isotopes in the condensate indicate the temperature of condensation at the time, allowing for ice cores to be used in global temperature reconstruction. In addition to the isotope concentration, the air bubbles trapped in the ice cores allow for measurement of the atmospheric concentrations of trace gases, including greenhouse gases carbon dioxide, methane, and nitrous oxide. The air bubbles may also contain traces of aerosols, which are produced in great concentrations during volcanic eruptions.
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Earth & Climate News
January 29, 2026
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Jan. 15, 2026 New research shows tropical forests can recover twice as fast after deforestation when their soils contain enough nitrogen. Scientists followed forest regrowth across Central America for decades and found that nitrogen plays a decisive role in how ...
Jan. 15, 2026 In the rapidly disappearing Atlantic Forest, mosquitoes are adapting to a human-dominated landscape. Scientists found that many species now prefer feeding on people rather than the forest’s diverse wildlife. This behavior dramatically raises the ...
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Jan. 27, 2026 The Ediacara Biota are some of the strangest fossils ever found—soft-bodied organisms preserved in remarkable detail where preservation shouldn’t be possible. Scientists now think their survival ...
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Jan. 14, 2026 Earth’s oceans reached their highest heat levels on record in 2025, absorbing vast amounts of excess energy from the atmosphere. This steady buildup has accelerated since the 1990s and is now ...
Jan. 13, 2026 Honey bees can normally keep their hives perfectly climate-controlled, but extreme heat can overwhelm their defenses. During a scorching Arizona summer, researchers found that high temperatures ...
Jan. 13, 2026 Scientists tracking Earth’s water from space discovered that El Niño and La Niña are synchronizing floods and droughts across continents. When these climate cycles intensify, far-apart regions ...
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