Climate Change Flashcards
What is paleoclimatology?
the study of the Earth’s past climates through proxy methods
What are the three methods for long-term climate reconstruction?
- isotope analysis
- ice cores
- ocean sediment core
What is significant about the climate of the past 70 million years (3)?
- scientists have been able to reliably recreate climate
- continents have been stable throughout this time
- relatively rapid warming of the atmosphere
What are some characteristics of the climate of the past 70 million years (3)?
- warmer
- tropical environments extended further
- cooling trend 50 million years ago
What is significant about the climate of the past five million years (3)?
- oversaw the evolution of modern humans
- rise of agriculture and civilizations
- included an ice age
What is significant about the climate of the past 20,000 years?
there have been more sources of data to analyze climate
What is dendrochronology (4)?
- each ring represents a year of growth
- the thicker the ring, the wetter the conditions
- the thinner the ring, the dryer the conditions
- scars form forest fires
What are the mechanisms of natural climate change (4)?
- solar variability
- Earth’s orbital cycles
- continental position and topography
- atmospheric gases and aerosols
How does solar variablity affect climate change (4)?
- variations in amount of energy coming into Earth’s system
- solar output has increased by 1/3
- changes in the sun’s magnetic field
- susnpot activity
How does Earth’s orbital cycles affect climate change (5)?
- distance between Earth and sun varies
- elliptical orbit around sun varies
- shape of ellipse varies
- Earth’s orientation towards sun
- axial tilt varies
How does continental position and topograpy affect climate change (4)?
- composition of continents impacts atmospheric and oceanic circulation
- example: formation of Himalyan Mountains affects jet stream and rain shadow
- example: formation of Panamanian Bridge prevents ocean flow
- position and structure impacts Earth’s albedo
How do atmospheric gases and aerosols affect climate change (3)?
- more carbon dioxide = warmer
- less carbon dioxide = cooler
- aerosols cause cooler conditions
What is feedback (3)?
- feedback: systems produce outputs that influence their own operations
- positive feedback: feedback amplifies system changes; destabilizes system
- negative feedback: a reduction in system changes; stabilizes system
What are some examples of feedback that impact climate (2)?
- ice-albedo feedback
- water vapor feedback
What is the carbon budget?
the exchange of carbon between sources and sinks in all of Earth’s spheres
What is the Carbon Cycle (3)?
- some processes remove carbon from the atmosphere (photosynthesis)
- some add carbon to the atmosphere (respiration and decomposition)
- must remain balanced
What are some human impacts on the Carbon Cycle (2)?
- clearing forests: decreases carbon sinks
- industrial revolution: burning of fossil fuels
What is the Keeling Curve?
- shows increase of carbon dioxide since 1955
- fluctuation caused by seasonality and photosynthesis
How do oceans affect the carbon cycle (5)?
- absorption of carbon by ocean results in smaller than expected amount of CO2 in atmosphere
- absorption causes formation of carbonic acid in ocean
- ocean acidity negatively impacts marine life
- the world’s oceans have absorbed about 50% of atmospheric carbon
- as the ocean’s temperature increases, its ability to dissolve carbon decreases
How do plants affect the carbon cycle?
- plants grow at a quicker rate and store more carbon
- but as temperature increases, photosynthesis decreases
What serves as evidence for present climate change (5)?
- sources of climate data
- rising temperatures
- melting ice
- rising sea levels
- increased atmospheric water vapor
What are some sources of climate data (4)?
- weather data
- satellites
- weather balloons, ships, buoys, etc.
- aircrafts
How do rising temperatures explain climate change (2)?
- warmest time in last 120,000 years
- increse in 20th century temperature happened faster than any other increase in the last 1,000 years
How does melting ice explain climate change (3)?
- melting sea ice does not increase sea level, but exposes lower albedo ocean water, resulting in increasing temperatures
- glacial ice is decreasing in Antarctice and Greenland
- permafrost has been thawing
How do rising sea levels explain climate change (2)?
- by-product of melting ice in polar environments
- happening faster than previously thought
How does increased atmospheric water vapor explain climate change (3)?
- increasing since the 1970s
- by-product of increasing temperature
- results in more frequent and extreme weather events
What is the primary cause of worldwide temperature increases?
increase of greenhouse gasses in atmosphere
How do greenhouse gasses affect climate change (2)?
- higher levels of greenhouse gasses absorb more longwave radiation trying to exit Earth’s atmosphere
- contribution to climate change depends on type of gas and how long gas remains in atmosphere
How has the increase in carbon dioxide contributed to climate change (3)?
- most prevalent of greenhouse gasses
- lasts 50-100 years
- primary sources: fossil fuels (70%), biomass burning, forest removal, industrial agriculture, cement production
How has the increase in methane contributed to climate change?
- 2nd most prevalent
- lasts about 12 years
- traps more heat than CO2
- primary sources: livestock, mining coal, oil, natural gas, rice farming, burning vegetation
How has the increase in nitrous oxide contributed to climate change?
- 3rd most prevalent
- lasts about 120 years
- primary sources: commercial agriculture (chemical fertilizer)
