Download 7.3 – Effects of Climate Change on the Lithosphere

7.3 – Effects of Climate Change on the Lithosphere
 soil dries out due to desertification
 soil becomes unusable due to excess fertilizer (nitrates
added to soil cause it to burn grass & other plants)
 soil becomes acidic due to acid precipitation
 reserves of fossil fuels under Earth’s surface dry up
7.3 – Effects of Climate Change on the Biosphere
 effects on plants & animals have already been discussed:
o melting glaciers & polar bears
o habitat loss due to deforestation & land organisms
o loss of producers to absorb CO2 from the atmosphere
o acidification of the oceans & aquatic organisms
o desalination of the oceans & all organisms
Effects on humans:
 hotter weather  more prone to disease surviving in more
Northern climates
 location of fertile land will more North  people in Southern
areas will have less access to food
 ocean levels rising  people in low-lying countries will be
forced inland
 increased intensity & frequency of storms  loss of shelter
for humans & other organisms, more human deaths, more
risk for disease (e.g., waterborne illness)
o see the graph on p. 299 of your textbook
 shortage of food (due to desertification)  starvation
 higher Humidex, more smog days  human health issues
Read the Case Study on p. 294-295 of your textbook. Try to
link the Walkerton water contamination to climate change.
9.1 – Records of Past Climates
paleoclimatologists = scientists who study past climates
from thousands of years ago
o pronounced PALE – ee – o – klime – ah – tall – ah – jist
 paleoclimatologists use trees, fossils, sedimentary rock,
coral reefs, and ice core samples to determine what
climates were like thousands of years ago
proxies = biotic or abiotic factors that indicate what past
climates were like
o common examples include tree rings, fossils, and
ice core samples
Tree Rings
 indicate what climate was like in the recent past
 older (& larger) trees can give indications about climate up
to a few hundred years ago
o some tree trunks from archaeological sites can tell
what climate was like thousands of years ago
 every year, a tree grows a ring
o the size & colour of the ring indicates what the
temperature & rainfall was like that year
■ wide ring = wet & cool weather
■ thin ring = dry & hot conditions
o a dark ring indicates growth during late summer
o a light ring indicates growth in the spring
Complete Activity 9-2
on p. 352 of your
textbook in table
groups
Ice Core Samples
 sheets of ice that cover places like Antarctica, Greenland,
and the Arctic have built up over hundreds of thousands of
years
 like tree rings, layers of ice & snow accumulate year after
year
 scientists drill into the layers of ice and extract a cylinder of
ice that they use to determine the composition of the
atmosphere years ago
o see Figure 9.2A on p. 353
 the deeper scientists drill, the older the ice they access
o scientists have drilled over 3 km deep into ice
sheets, which got them an ice core sample from
over 800 000 years ago!!
Evidence gathered from ice core samples :
1. Types of particles trapped in the ice
o dust, ashes, salts, pollen, etc., give clues about past
events and conditions like volcanic eruptions,
meteorite impacts, forest fires, vegetation cover, etc.
2. Size & shape of ice crystals
o physical characteristics tell about the temperature &
humidity at the time the ice crystals formed,
depending on if the ice is in the form of snow, hail,
etc.
3. Composition of air trapped in bubbles in the ice
o when water freezes, tiny air bubbles become
trapped inside the ice
o these pockets of air incidate which greenhouse
gases were present in the atmosphere when the ice
formed
4. What the water that composed the ice was made of
o H2O always has varying amounts of isotopes of H &
O (oxygen-16 is the most common, i.e. the one
found on the Periodic Table, but other isotopes
include oxygen-17, oxygen-18)
o H2O containing “heavy” oxygen (oxygen-18) freezes
at a higher temperature and takes longer to
evaporate than “normal” H2O
o during a warming phase, more oxygen-18 is present
in ice, whereas during a cooling year, more “normal”
oxygen is present
o still want to know more? Consult p. 354 of your
textbook and follow though Figure 9.3
Paleoclimatologists
removing a sample of ice
from a glacier in Antarctica
 in Temp.
 in CO2 levels
 in Dust levels
Look carefully at the graphs above. Have CO2 levels ever
been as high as today’s levels?
Why, then, are scientists warning of catastrophe in the
coming decades?
Because past spikes in CO2 were a result of natural disasters
like volcanic eruptions, meteorite strikes, etc., not a result of
human activity
Speculate as to the shape of the graph for temperature that
we could draw of the same ice core sample above.
temperature (C)
year
9.3 – Bias
bias = leaning towards one perspective or point of view
instead of being objective
o e.g., Ms. Winter is biased towards the theory of
evolution due to her science background
 some sources claim climate change is fiction
 scientists claim climate change is real
 see p. 372 for questions to ask yourself about bias when
reading a news article, especially on a topic of controversy
9.3 – Climate Change Initiatives
1. What was the Kyoto Protocol? Was it a success?
2. How much of the worldwide greenhouse gas emissions are
produced by Canada?
3. What does IPCC stand for? When was it established?
What is its objective/goal?
4. What took place in 1979 to bring the topic of climate
change to the forefront of international discussions among
countries?
5. Name 2 economic initiatives that the government has
introduced to attempt to reduce greenhouse gas emissions.
Which of the two do you think is a better option?
6. Complete Q # 5 on p. 381.