Download Chapter 11.1 Natural Causes of Climate Change

Chapter 11.1 Natural Causes of Climate Change
Climate __________________________________________________________
is the average conditions in the atmosphere in a large region over
___________________________________.
(clouds, precipitation, temperature,
30 or more years
humidity, atmospheric pressure, Solar radiation, wind)
BC has a range of climate zones.
Biogeoclimatic zone is a region with
specific types of plants, soil, geography,
_____________________________
and climate
______________.
BC has 14 different
Biogeoclimatic zones.
Paleoclimatologists: Study past climate
conditions in order to better understand
future climate conditions.
Plant fossils, Ice core samples,
tree rings.
BC has experienced many changes in climate
21000 years ago a large part of Canada was buried under
2km of ice.
By looking at Ice core samples paleoclimatologists are
able to analyze the ___________________________
the composition of the
__________________________________________
atmosphere
over the last 650 000 years.
earths tilt
Many factors affect climate: composition of the earths atmosphere, ____________,
rotation and _______
orbit
water cycle ______________,
ocean currents
_______
around the sun, _____________,
carbon cycle and ___________________.
catastrophic events.
_____________
Natural Green house effect: absorption
Of thermal energy by the atmosphere
gases absorb and emit
Green house _____________________
energy as thermal radiation.
_________________________________.
The earths tilt and orbit causes the
earth to experience distinct seasons
It affects the angle of incidence of sun light.
____________________________________.
The earths tilt varies between 22.1o and 24.5o
every 41000 years.
The earth’s rotation has a wobble of about
___________________________
12000 years. ______________________
This also affects the angle of
_________________________________.
Incidence of the sun’s rays
The earths orbit around the sun also changes
Over 100000 years causing the earth to
___________________________________.
orbit farther away from the sun
It is believed that these factors have caused
Ice ages to occur in the past.
Concept Check p. 465-470
1. What is a biogeoclimatic zone
2. How has the climate in Canada changed since 21,
000 years ago?
3. Name one method paleoclimatologists used to
determine how much CO2 was in the atmosphere in
the past
4. What is the greenhouse effect?
5. How does earth's tilt affect the amount of solar
radiation that reaches us?
6. What is the shape of Earth’s orbit around the Sun?
The Water Cycle: The circulation of
water _________________
on, above and below the Earth’s
surface.
Water vapour H2O is the most abundant
greenhouse gas in the atmosphere.
________________
High temperatures increase the
evaporation of water and the amount
of water vapour that air can hold.
Ocean Currents:
Convection currents in the ocean
___________________
transport large amounts of ________
heat
________________
around the earth.
and water
Deep ocean currents (below 500 m) and
Surface currents are connected to
global climate
_______________________.
density
These currents are driven by _______
differences Density is affect salinity
__________.
and temperature.
Salty and cold water are more dense.
As ice forms it makes water saltier as it melts it makes water less salty.
warm temperatures cause evaporation which makes water saltier.
precipitation makes water less salty.
______________
Surface currents exchange heat with the atmosphere affecting weather and climate.
Thermocline a transition zone that separates the deep cold water from the warm
surface water.
deflects water as well as wind to the right
The Coriolis affect ________________________________________
in the northern
left
hemisphere and to the ______________
in the southern hemisphere.
(El Nino-Southern Oscillatioin ENSO)
El Nino
warm
When surface waters become ________
off the coast of Ecuador and Peru.
this results in mild warm weather on the
Coast of BC and eastern Canada.
La Nina
Cool
surface waters cause unusually
________________
Warm weather in southeast region of
North America and unusually cold in
the northwest.
Remember The Carbon Cycle
Catastrophic Events: Large scale disasters have happened many times in Earth’s history.
sunlight
Large volcanic eruptions: can block out _____________.
Release large amounts of
sulfur
dioxide
sulfuric acid
_________ (SO2) into the atmosphere forming ________________
(H2SO4). These
stratosphere reflecting large amounts of sunlight back into space.
droplets travel in the _________
The Tambora Eruption in 1815 in Indonesia
lead to the Year without Summer in Europe in 1816.
Meteorites have caused more significant effects
blocking out sunlight. It is believed that this
contributed to a mass extinction 65 million
years ago when a meteorite hit
the coast of Mexico.
Ash layers can be seen in Kamloops
From an eruption 7700 years ago in
Mount Mazama.
“Civilization exists by geological consent –
subject to change without warning”
Will Durant
Concept Check p. 471-473
1. What is the most abundant greenhouse
gas in the atmosphere?
2. What property of water is affected by
temperature and salinity?
3. What is the name of the event that causes
periodic warming of waters in the Pacific
ocean?
The current change in global temperature over the
Last 60 years has caused a 0.74 oC increase in
_____________
temperature. Computer models suggest we could
experience as high as 6oC increase in average
temperature in the next 100 years.
The difference between an ________________
the difference between
______________________________________
an ice age and current Climate is about 3-5oC.
The complexity of the climate systems means
computer models can not accurately predict the
outcome.
Human activities have caused a
Net addition of 15 gigatonnes of carbon
dioxide to be added into the atmosphere
Enhanced Greenhouse effect
_________________________________
Atmosphere absorbs more radiation
_________________________________
and emits more infrared radiation.
Global Warming Potentials (GWP)
CO2= 1
Nitrous oxide(N2O)= 298
Methane(CH4)=25
Chlorofluorocarbons(CFC)= 4750-5310
revolution has lead
Carbon Dioxide: Industrial
_______________
To a massive increase in our consumption of
___________________.
Fossil fuels.
- _____________
Deforestation removes a carbon sink and
releases CO2 back into the atmosphere.
Reduce energy demand and production.
- ________
- Use Energy from sources other than fossil fuels
Reforestation is another way to remove CO2.
- _____________
Methane CH4: Methane is less
abundant in the atmosphere but
more efficient than CO2.
decomposition
Released from _______________
animal digestion
(landfills) and ________________
fossil
(Cows) and extraction of _______
Fuels.
__________.
Nitrous Oxide (N2O): Produced from
biological processes and __________
nitrogen
_____________
as well as automobile
fertilizers
______________.
exhaust.
Ozone(O3): forms the ozone layer
10 to 50km blocking out UV radiation.
However ozone forms from ________
fossil fuel
____________
Combustion and ______________.
air pollution.
Chlorofluorocarbons: Man made
Chemicals used in refrigerators.
These resulted in the ____________
ozone hole
As well as being powerful ________
greenhouse
___________.
Gases.
Albedo and Climate: Some pollutants
affects the amount of solar radiation
Reaching the surface.
Different substances have different
Albedo forests and ice are thought
high albedo
To be important due to __________
Concept Check
• What is the difference between the natural
greenhouse effect and the enhanced
greenhouse effect?
• What does GWP describe
• List the greenhouse gases that are
released when fossil fuels are burned
• Name a greenhouse gas that doesn’t
occur naturally
Global Impact of Climate Change: Some models predict a _______________
6oC increase in
____________________________________________
in the next 100 years.
Temperature and a 88cm rise in sea levels
Impacts of climate change on Canada:
The affects of global warming could be
More severe in Canada because we are
in the northern hemisphere.
_____________________are
beginning
As
sea ice and Permafrost
to melt affecting life in the north.
Weather patterns are changing with
increased ___________________.
precipitation
In Alberta aspen trees bloom 28 days earlier than 100 years ago.
_______________
could be severely affected by these changes.
Agriculture
Changes in water temperatures and currents can devastate fish populations affecting
fisheries.
_________________.
Forestry
____________
may also be affected with increases forest fires and insect infestations.
Increased temperatures may affect health causing worse ___________
air pollution in the summer.
__________________________
to survive farther north and increased population.
Disease carrying insects
More ___________________
may damage infrastructure causing power outages.
violent storms
Impacts of Climate Change
on British Columbia:
A possible 30cm rise in sea
level would cause significant
flooding
threat of ___________
to coastal
communities.
Drought will increase forest fires
_________
and the spread of certain trees and
grasslands.
Salmon may migrate north towards
colder water being replaced by
Mackerel and tuna.
Glaciers
_______________
are an important
source of fresh water in BC climate
change is causing them to shrink
Uncertainty and Decision:
1) Climate change will not greatly affect our lives or environment
2) Climate Change will cause drastic changes in weather patterns that will greatly affect
our lives and the environment.
Precautionary Principle: A lack of complete scientific certainty should not be used as a
cost-effective measures to prevent _________________________.
serious environmental damage
Reason to postpone
___________________________