Consequences (lec 19) Flashcards
Can past warm periods and ice ages be attributed in part to the earth’s position relative to the sun
Yes
Can current global warming be explained by Milankovitch cycles ?
No
Where is our global climate headed
6.1° F
How can we make reliable predictions about future climate?
Predictive models
Climate science use computer models to take into account major factors that are known to have affected past climate and feed data into a model to see what matches up with warming that has been observed .
Predictive models
What models match the actual historic temperature trend?
Ones that include human releases of greenhouse gases
Factors that can affect global climate these can be positive ( increase temp) or negative (decrease temp)
Forcers
Positive forcers
Black soot on snow
Solar radiance
N2O
Halocarbons
Tropospheric ozone
CH4
CO2
Negative forcer
Cloud albedo effect
Aerosols
High- albedo land use
Stratospheric ozone
Temp rises
More ice melts
More water is exposed and absorbs heat
Positive feedback loop
What also releases methane?
Warming
What increases warming?
Meting ice by changing albedo
Effects of tundra thawing
Releases methane and CO2
Large positive feedback loop
Methane hydrates at bottom of shallow polar seas
A plankton that drifts to the upper layer of the ocean and forms the basis of virtually all marine food webs
Emelliana huxleyi
Emelliana..? (Neg feedback loop)
Abdorbs C02 in photosynthesis
Reflects solar radiation with cocolith plates
Releases vapor dimethyl sulfate
Scatters incoming radiation and forms nuclei for greater cloud cover
Vapor dimethyl sulfate
If emelliana declines it becomes what?
Positive feedback loop
What causes Emelliana populations to decline
Warmer ocean
High levels of dissolved CO2 (390ppm) we are at 400ppm
Acidification of Ocean from CO2 ( shell is calcium carbonate)
Where does extra CO2 go?
26% absorbed by oceans
46% in atmosphere
28% used by plants
Can plants use CO2 in many ways besides just growth?
Yes
More C02 = more ? ( plants)
Pollen and Poison Ivy
By 2050 Georgia is expected to be ?° warmer?
5-9
? Will have consequences for human health, drought and wildfires
Increase in very hot days
Ocean heat content
Makes storms more severe
Is ice melting and rebuilding?
No
Northwest passage opened up due to
Melting ice
Sea level is certain to rise —- in less than 100yrs
3-6 ft
Greenland melting would raise sea level by
23 ft
Drivers of sea level rise
Thermal expansion (warming of oceans)
Change in land ice
Sea level changes on US coastlines 1958- 2008
8 in
In 2005 how many sq mi of land and wetlands were lost due to?
Hurricane Katrina and Rita
On coastal GA water moves inland ?
1000’ with every 1’ tise in sea level
