Global Change Flashcards
(28 cards)
What is global change?
Promotes changes in land-atmosphere-ocean systems
What are these global changes that we made?
- Atmospheric change
- Land cover change
- Oceanic change
- Climate change
Atmospheric change
Changes in the chemical composition of the atmosphere
Land cover change
A change in the physical or biotic state of a site
- 40%+ of earth’s surface is composed of croplands and pastures
- Huge areas of natural vegetation
Oceanic change
Changes in the physical, chemical, and/or biotic state of the oceans
Climate change
Changes in atmospheric circulation, pressure, temperature, precipitation
What is the trend for CO2 concentration?
They’re at their highest level since the last 650,000 years
What are the indicators of human influence towards the atmosphere?
Increase in:
1. Carbon dioxide concentration
2. Nitrous Oxide concentration
3. Methane concentration
4. Sulfate aerosols deposited in Greenland ice
How do plants respond to CO2?
Respond positively however response declines over time (adjusts to CO2 in environment)
What are the negative affects of CO2 in ocean life?
- Causes acidification in ocean waters on a global scale
- Causes degradation of animal shells or anything made of calcium
Natural causes of climate variation
- Atmospheric clarity
- Variation in solar activity
- Climate oscillations
Atmospheric clarity
Volcanic eruptions, meteor strikes
Variation in solar activity
Solar flares / solar dimming
Climate oscillations
A recurring climate pattern
- El Nino/Southern
- Pacific decadal
- Atlantic multidecadal
- North Atlantic
- Madden Julian
Human causes of climate variation
Enhanced greenhouse effect
Enhanced greenhouse effect
Increases in gases from fossil fuel burning and deforestation
How can we detect climate change?
- Ice cores
- Lake sediments
- Tree rings
- Direct observations
Ice cores - observations
Between greenhouse gases and climate
Lake sediments - observations
Between pollen assemblages and climate
Tree rings - observations
Link thickness in tree rings to changes in climate
Direct measurements
Weather stations are used to measure climate
What are the natural causes of oceanic temperature change?
Hatched region / green triangles have little resemblance to observed temperatures - red dots
What are the human causes of oceanic temperature change?
Hatched region is highly correlated with observed temperatures - red dots
What is the main reason for oceanic temperature changes ?
Human causes - green house gas emissions
