13.3

• Paleoclimatology is the branch of science that deals with climates prevalent at particular times in the geological past
• Climatologists and geologists use global climate models (GCMs) to understand how present-day factors affect the climate
• Stratigraphic Record is the product of a geochemical system consisting of geochemical setting, climate, and processes of sediment production
• Glacial till is composed of unconsolidated sediments eroded and incorporated by a moving glacier
• Paleontological evidence refers to the remains and traces of organisms that once existed or are still existing
• The best climate indicator is microplankton, which depend on water temperature
• Oxygen-isotope ratio analysis estimates past ocean temperatures by looking at the ratio of stable oxygen isotopes, 18O and 16O, which are temperature-dependent in water
• Growth rings indicate the age of a tree or shells
• Very broad rings generally indicate a good growing year
• Narrow rings signify a lack of sun or water, or damage by fire
• Off-center rings indicate exposure to high winds on a side
• Great Oxygenation Event enriched our atmosphere with essential oxygen gas initiated by the evolution of photosynthetic organisms
• Cyanobacteria are the first oxygen-producing organisms
• Loss of carbon dioxide after photosynthetic organisms evolved led to “snowball Earth” conditions in the Huronian glaciation
• Greenhouse or hothouse periods are extremely warm periods
• Icehouse periods are extremely cold periods
• Positions of continents and continental drift, Volcanism, Uplift, Life evolution, Mass-extinction are factors of long term climate change
• Positions of continents and continental drift dictate ocean current patterns and change the latitude of landmasses
• Volcanism increases the concentration of the atmosphere’s greenhouse gases over time, causing global warming
• Uplift exposes certain elements to weathering, such as CO2
• Large uplift events can disrupt atmosphere circulation and form highland climates
• Life evolution refers to the extinction or appearance of certain organisms which led to great climate upheavals
• Mass-extinction events can indicate a sudden and violent change in climate, with long-lasting effects
• In the past 15,000 years, the temperature has generally increased with minor fluctuations
• Holocene maximum, Medieval Warm Period, Little Ice Age are short term climate change
• The Holocene maximum exhibited warmer global temperatures which caused ancient civilizations to thrive
• The Medieval Warm Period resulted in larger harvests, affecting human civilization prosperity
• The Little Ice Age was characterized by glaciation, crop loss, and scarcity
• Solar fluctuations affect the amount of energy Earth receives, with sunspots appearing every 9 to 11 years, releasing large amounts of radiation
• Milankovitch Cycles refer to changes in the tilt of Earth’s axis, the precession cycle, and the eccentricity of the orbit
• Plinian eruptions release a large volume of ash into the atmosphere, causing global temperatures to cool down
• Ocean currents are easily changed, causing subsequent climate changes
• Albedo is the amount of solar radiation reflected by the surface, affecting the planet’s energy input
• Human activity has increased greenhouse gas release, exceeding the Earth system's capacity to absorb them
• The Intergovernmental Panel on Climate Change (IPCC) of the United Nations and World Meteorological Organization consolidates and summarizes studies on climate change
• Solar fluctuations, Milankovitch cycles, Plinian eruption, Ocean currents, Albedo are factors that caused short term climate changes