Climate Variability and Change Flashcards
What is the human-enhanced greenhouse effect?
The leading cause of global waring, atmospheric CO2 levels have increased by nearly double over the past 250 years. Methane, which is 25x more potent, has also increased by 150%.
What is paleoclimatology?
The study of past climate trends by using proxy measurementd to gauge climate changes.
What is dendrochronology
1 of the 6 climate proxies that scientists use to reconstruct past climates, it analyzes tree rings in order to establish dates for catastrophic events, such as drought, flood, fires, and major changes in temperature.
What is oxygen isotope analysis?
1 of the 6 climate proxies that scientists use to reconstruct past climates, it measures the amount of 16-O and 18-O in the atmosphere to determine existence of major climate changes.
What does an abundance of 16-O in oxygen isotope analysis tell us about the climate?
The abundance of this oxygen isotope tells us that there was homeostasis.
What does an abundance of 18-O in oxygen isotope analysis tell us about the climate?
An abundance of this oxygen isotope in oxygen isotope analysis tells us that there was an ice age because the other type of isotope became trapped in glaciers.
How do oceanic sediments affect oxygen isotope analysis?
Floraminafora calcium shells layer up and retain 16) levels during the period.
How do coral reefs affect oxygen isotope analysis?
Polyp exoskeletons retain 16-O levels of the time.
What is Ice Coring?
1 of the 6 climate proxies that scientists use to reconstruct past climates, it involves drilling into glaciers to reveal records of snow fall.
What do high 18-O levels in an ice core tell us about the climate conditions of the time?
An abundance of this oxygen isotope in ice cores indicates higher temperatures because more of these molecules evaporate and become snow.
Why do air pockets in an ice core help scientists make conclusions about the climate conditions of the time?
This feature of ice cores provides pure samples of 18-O and 16-O from the time.
What is palynology?
1 of the 6 climate proxies that scientists use to reconstruct past climates, it takes samples of pollen from sediment to determine the lifespan of plants.
What is radiocarbon dating in the context of palynology?
Provides age of organic plant material from up to 50k years ago by sampling relative amounts of two carbon isotopes, 14-C and 12-C.
What is a feature of 14-C in the context of palynology?
This carbon molecule decays at a known rate into 14-N, allowing scientists to estimate the age of a plant.
What is a feature of 12-C in the context of palynology?
The more stable of the two sample carbon isotopes during palynology, it more or less remains the same over time.
