Climate Global Change: Effects
Fall 2008, Lecture 9
1
Dealing with GCC
How will climate change affect the earth?
A. In the short term (years to decades) B. In the intermediate term (by 2100) C. Longer term effects
2
Mitigation of Effects
How we can mitigate the effects we have on climate? We must realize that mitigation efforts will not be sufficient to maintain the status quo, because our best efforts cannot stop the climate changes we have already set in motion At best, we can slow these changes, and perhaps reduce their impacts
3
Adaptation
So we must necessarily think of ways of adapting to climate change
We must do this while adapting to a sharp reduction in the supply of petroleum in the short term, to increasing problems of pollution, and perhaps most importantly, to a rapidly expanding population in the short to intermediate terms
4
What Will the Changes Be?
Before we can begin plans to adapt, we must know what the changes will be We also need to keep in mind that change may be good or bad, but such judgments are nearly always subjective
5
Predicting Change
Some changes are already appearing Some changes may be predicted with some confidence with existing computer models Others we can speculate about
6
Currently Observed Change
Two areas where change has already begun will be discussed These are:
Sea level rise Effects on the polar regions
7
Unknown Effects
Speaking of ice near the top of North America, physical oceanographer Humfrey Melling of the Institute of Ocean Sciences (Sidney, British Columbia) says, "Every 10 years or so, for reasons we don't understand, there's a dramatic loss of ocean ice"
8
Diatom Evidence
Diatom mats hang from the bottom of Arctic ice These diatoms rain on the seafloor as they die, providing food for worms and crustaceans, which in turn are food for the bottom-feeding whales Net effect of diminished diatom Scanning electron mats on the overall ecology is an micrograph of a marine open question
diatom
9
Potential Positive Effect
Diminished ice cover would increase the production of phytoplankton, which are consumed by zooplankton, which are eaten by Arctic cod Cod are food for both humans and Arctic seals
Plankton
Arctic cod
10
Potential Negative Effect
Polar bears spend much of their life on the ice They eat seals from late spring to midsummer, building up energy reserves to see them through many lean months Recession of the ice will give the seals more open water away from the predatory bears
11
Indigenous Arctic Peoples
Indigenous Arctic peoples are used to adaptation Hunting early or later, hunting...
GCC_Effects_F08_Lect09