Lecture 7/8 Flashcards
Define weather
atmospheric conditions over short time periods (e.g. hours, days) within small geographic areas
Define climate
atmospheric conditions (e.g. precipitation, temperature) across large geographic regions over long periods of time (e.g. decades, centuries)
What are the 3 influences on the Earth’s climate
- sun
- atmosphere
- oceans
How does the sun affect the earth’s climate
without it, Earth would be dark and frozen
How does the atmosphere affect the earth’s climate
without it, Earth’s temperature would be colder
How do the oceans affect the earth’s climate
shape climate by storing/transporting heat/moisture
What are the two factors involved in climate
- average annual precipitation
- average annual temperature
What does climate change focus on
trends and variations in the earth’s climate
Define global warming
An increase in Earth’s average temperature
- average temperature naturally increases but rapid change is due to human activity
What are the 6 factors affecting the absorption of solar radiation, leading to climate change
- orbital cycles of Earth
- solar output variations
- ocean absorption of atmospheric gases
- ocean circulation patterns
- changes in absorption of solar radiation by Earth’s surfaces
- changes in atmospheric gases (especially ‘greenhouse gases’)
Define orbital cycles
periodic long-term changes in Earth’s rotation and orbit around Sun
- (referred to as Milankovitch Cycles)
Define solar output variations
drives temperature change on Earth’s surface because of variation in solar flare activity and solar storms
Define ocean absorption
the ocean holds 50 times more carbon than the atmosphere and by absorbing CO2 from the atmosphere, the ocean acts as a carbon sink that maintains stable levels of atmospheric gases
Define ocean circulation
worldwide currents changing - warmer, fresher water moves along surface; and colder, saltier water moves deep beneath the surface
- impacted by melting of glaciers and polar ice caps
Define changes in absorption of solar radiation
changes in atmospheric gases can alter the amount of solar radiation absorbed by the Earth’s surface (= albedo)
- with more absorption, Earth’s surface increases in temperature and emits more infrared radiation that warms lower atmosphere
Define changes in atmospheric gases
changes in atmospheric gases that absorb infrared radiation (e.g. water vapor, CO2, CH4, N2O, chlorofluorocarbons) can alter amount of solar radiation absorbed by the Earth’s surface
Define CO2 as an atmospheric gas
- not most potent
- most abundant / long lived
- major contributor to climate change
Define CH4 as an atmospheric gas
- very potent
(25 times greater than CO2) - less abundant / short-lived
- due to human activities
Define NO2 as an atmospheric gas
- very potent
(300 times greater than CO2) - less abundant
- due to human activities
Define the greenhouse grass effect
- With more solar absorption, Earth’s surface warms and emits more heat that warms the lower atmosphere
- Warming of lower atmosphere further warms Earth’s surface
What does PCF stand for
Permafrost Carbon Feedback Loop