Lecture 9 – Climate change final
1. IPCC – Summary
a. Human and Natural Drivers of Climate Change
b. Green house gases have been offset by aerosols
i. Lot of aerosol effects are from burning dirty coal , sulfur emmisson from
automobiles, diesel particular emission filters. The coal their exhaust onto a
filter, and it clogs up. They put their exhaust to a filter that gets clogs up and
which they burn for 1000 degrees, and they out a huge amount of aerosol.
ii. China and east asia is putting out lot of aerosols. 50 years from now into the
future, the technology will get modified. The expectation is this amount will
reduce with time. and co2 will get warmer. To some degree there is a masking
of warming with aerosol effects.
iii. Aerosol effects are regional, Co2 effect is global.
1. East asia, you are getting huge amount of aersol cooling effect, but you
wont be feeling that if you take it somewhere else.
iv. Aerosol effects are regional, co2 effects are global
1. If you are still in the middle of the pacific you are getting warmer, no
2. If you are somewhere like in china, you get cooling effects because of
i. Extreme droughts, - changes in precipitation, and seal surface temperateue,
snow ica caps melting; storms – changes in wind patterns whichaffects the extra
tropical wind tracks, and temperature pattersn, antroprogenic reason, extreme
heat effects, predictions from global warming that there will be extreme
weathers, -predictions!!!! On global warming!!! EXPLAIN THESE!!!!! On
midterms!!! Not only increasing temperature.
b. Sea level changes:
i. In Bangladesh the increasing temperature is huge impact, in case their land gets
ii. Over the ladt 100 years it was 115mm. 15 cm.
iii. The document goes through where the sea level is coming from.
1. Glaciers,/ ice caps
2. Sea ice
3. Most of the temperature changes have been measured in ground, but now it has been
measured that the temperature also increases in air. This hadn’t been true earlier.
4. Arctic is an ocean, no land in North pole. and doesn’t matter that as ice is melting, because it
doesn’t change the height of the ocean. It is already in the ocean. What matters is if snow/ice on
the land melts. If you start melting the Greenland ice cap, Antarctic, mountain glaciers, then you
can out that water from land to ocean it is going to change.
5. During ice ages the oceal level would have been several m less. Like 30,000-20,000 years ago. 6. Records of changes in sea lavel changes:
a. Discovered that sea level is going down within the last 50 years. Which seemed
strange.what seemed to be happening was, we should count on what was pulling them
down, not only the water level.
b. What was pulling on that water. The fact that Greenland was melting reducing the
gravitational pole the Greenland has for the ocean in that part of the world.
c. Eg: we have a big mass of ice in Greenland melting and there’s less gravitational force
on the ocean. Ocean id getting pulled up little less.
d. Generally there are consensus reasons.
7. Second reason: warming of water.
8. roughly between the two mechanisms which is more important?
a. roughly half and half. 50-50.
9. There are no of other observations of climate change:
a. Temperatures is going up
b. Sea level is going up
c. Snow cover is going down
d. The winter seasons are chagetting shorternging. Less days.
10. Most of the temperature increase are measured with the moitors in tehg round, but what has
ow been verified is it is also increasing in the atmosphere.
a. Measured from balloons. Satellite measurements
b. 5 years earlier, this wasn’t true.
11. The average water vapor content has increased over the land and the ocean.
a. H2o is a greenhouge gas,
b. The temp rises due to CO2. The amount of water goes up, which is also a GHG.
c. Importance of h20 as a GHG: the most important GHG.
d. Then the temp goes up more. It is a positive feedback loop.
e. You don’t put up a microphone near a speaker, because it amplifies and amplifies it
f. There’s an intial motication to the system, nad the system responds by increasing that
g. Temp rises ware vapor rises temperature rises more water vapor increases.
12. Negative feedback in the climate system
a. If you put more water vapor into the atmosphere, there is another possibly of forming
b. Clouds are formed with condensation of water,.
c. temperature rise Water vapor rises cloud content increases albedo of planet
goes up temperature reduces
13. Major observation of climate change:
a. Sea ice. If you look at sea ice covered now, it is at a minimum now. It forms around
winter. Melts during summer and minimum around September. The minimum is
something about an average now. b. The north west passage: panama canal was built to go around. Because they couldn’t go
around the arctic to get to asia. In 2007, the north west passage was open. You could
have easily gone through from Europe to asia, without ice breakers.
c. Doesn’t mean the north pole is going to be free of ice in summer.
d. This is a good example of feedback.
e. You take up the temperature,
i. Put co2 in the atmosphere temperature rises sea ice melts albedo goes
down reflects less sunlight absorb more light temperature rises
ii. Page 7 – average arctic temperature increase at at least twice the global
average rate in the past 100 years. Etc..
f. Costal region:
g. Co2 goes into the ocean acidifies it ph goes down (somewhat, not a lot because it
is buffered) take up less co2.
h. This is a Positive feedback, because you are always taking up some amount of co2, and
then you are not taking up as much as you did before, rising the co2 in the atmosphere.
i. Fertilization effect -> plants go faster with higher co2
ii. Permafrost temperature of the top of the permafrost layer increased since
the 80’s in the arct