11.1 NATURAL CAUSES OF CLIMATE CHANGE

Name: Date:

Block: (Reference: pp. 464 - 481 of BC Science 10)

• Climate change is not new on Earth.

Earth has undergone periods of freezing followed by periods

of warming throughout its history.

DESCRIBING CLIMATE

• climate: ___________________________________________

___________________________________________________________________

Climate includes clouds, precipitation, average

temperature, humidity, atmospheric pressure, solar

radiation, and wind.

The size of the region can range from an island to the

entire planet.

BC has a range of climates due to its varied ___________.

• Climate and geography combine to allow specific organisms to grow.

Biogeoclimatic zones: ____________________________

____________________________

____________________________

____________________________

British Columbia has ____ distinct

biogeoclimatic zones.

LOOKING FORWARD BY STUDYING THE PAST

• Paleoclimatologists study:

__________ ___________- they may show if the

environment was cold and dry or warm and wet.

________ ________- show evidence of growing seasons

(yearly changes in the weather).

__________ _________________- can reveal types of

precipitation a region received in the past

• Fossils and sediments evidence from around the world indicate

that Earth’s climate has drastically changed _______ in the past.

• Ice ages and periods of warming have occurred _________ times.

21 000 years ago much of Canada and northern Europe was

under _____________.

• Ice core data show the composition of ________ in the

atmosphere when the ice formed.

gases can be trapped in the ice for thousands of years.

reveal CO2 levels for the past __________ years.

• Scientists have also tested the atmospheric air for CO2 for the

past _____ years

• Several factors that influence climate include:

1. Composition of Earth’s Atmosphere

• The Earth’s “natural greenhouse effect” is a closed system

that allows a narrow range of ___________________.

Some of the solar radiation that reaches the Earth’s

surface is reflected into the atmosphere.

Greenhouse gases in the atmosphere ___________ and

_______ thermal energy.

This keeps Earth an average of ____ºC warmer

than it would be otherwise.

More greenhouse gases could make it too warm.

2. Earth’s Tilt, Rotation and Orbit

• Earth’s ______ and _______ is responsible for seasons at

higher latitudes.

In the northern hemisphere…

in the summer, we are tilted ___________ the

Sun, _______________ the angle of incidence.

in the winter when we are tilted _______ from

the Sun, solar radiation has a _________ angle

of incidence.

Earth’s tilt _______ between 22.3º and 24.5º (currently

______º) in 41 000 year cycles.

Scientists believe when the tilt is the greatest

the seasonal changes would be the most ______.

• Earth “wobbles” as it ____________ on its axis.

The axis changes on a 23 000 year cycle

In about 12 000 years, the North Pole won’t point to

Polaris, it will point to ________.

• This will __________ the angle of incidence of

solar radiation.

• Earth’s _______________ around the Sun is elliptical, not

circular.

On a 100 000 year cycle, Earth’s elliptical orbit becomes

_______ circular.

When the orbit is most elliptical, Earth is farther away

from the Sun, so _______ solar radiation reaches

Earth’s surface.

• Scientists believe the combination of Earth’s tilt, wobble, and

shape of orbit have caused past ______ _________.

3. The Water Cycle

• The water cycle describes the circulation of water ___,

_____________, and _________ Earth’s surface.

water vapour is the most _________________

greenhouse gas in the atmosphere (70%).

When temperature increases, evaporation of water

and the capacity of air to hold water vapour _______.

More thermal energy is trapped in the

atmosphere, temperatures increase even more

at the Earth’s surface, and even more water

evaporates, etc.

4. Ocean Currents

• ________________ ______________ in the oceans move

large amounts of thermal energy all around Earth.

• Two types of currents that affect climate:

1. _________ ocean currents (below 500 m deep)

2. ______________ currents (up to 500 m deep)

• Deep ocean currents are driven by ___________ differences.

They behave like massive convection currents, with

_______ water rising in the tropics and ______

water from the higher latitudes replacing it.

Two factors that affect the density of water:

_______________________

• Cold water (found at the poles) is

more dense than warm water.

_____________ (salt content).

• Salty water (found at the poles) is

more dense than fresh water.

Cold, salty water will _____ below warmer, less salty water

• Large changes in ocean water density can _____________

current direction.

Create saltier water -> _______________ of

surface water or the formation of ______ .

Dilute salt water -> __________________ or the

___________ of glaciers.

• Surface currents are warmed by ________ radiation.

• Three factors that influence surface currents:

1. ____________

• drag surface water

2. ___________________________ (Coriolis effect)

• deflects the path of moving water to the right in

the northern hemisphere and left in the southern

hemisphere

3. __________________________________________

• affect the direction of surface currents

• thermocline: ______________________________________

_______________________________________________

________________ occurs when cold, deep water

rises above the thermocline, into surface currents.

Ex. ____ _________

Cool water at the surface of the eastern

Pacific Ocean causes warm winters in

southeastern North America, and cool

winters in the northwest.

____ _______ is the reverse: warmer water on the

surface of the Pacific Ocean results in warm winters

in the Pacific Northwest and in eastern Canada.

5. The Carbon Cycle

• Carbon dioxide is a very important _______________ gas.

Even though each molecule absorbs only a small

amount of thermal energy, there are more CO2

molecules than any greenhouse gas other than _____.

Without CO2 to trap ___________ radiation from

Earth’s surface, the average temperature of Earth

would be below freezing.

• The carbon cycle maintains a ______________ of CO2 in

the atmosphere.

Deep oceans and forested areas are ______

_______ (remove carbon from the atmosphere)

• CO2 dissolved in the ocean is converted to

_______________ ions (HCO32-), in

shells.

• Phytoplankton use CO2 for

___________________ at the ocean’s

surface.

_________________ of rocks is a carbon

_________ (release carbon into the cycle).

• __________ ______ (H2CO3) is formed

when water reacts with CO2 in the

atmosphere.

____________ are carbon sinks when growing and a

carbon source of CO2 when burned or when decaying.

6. Catastrophic Events

• Large-scale disasters quickly change atmospheric conditions.

Large ____________ ______________ can release

molten rock, ash, water vapour and sulphur dioxide, which

have cause temperatures on Earth to ______.

Ash __________ out sunlight.

Sulphur dioxide reacts with water vapour to

produce sulfuric acid, which can ___________

solar radiation back into space.

_________________ and other large pieces of rock

from space are thought to have caused even more

dramatic cooling.

Resulted in large quantities of dust, debris and

gases shot up into the atmosphere.

Believed to be responsible for some of Earth’s

largest _________ ____________________.

• 65 million years ago ->the extinction of many

____________________.

11.2 HUMAN ACTIVITY AND CLIMATE CHANGE

Name: Date:

Block: (Reference: pp. 482 - 501 of BC Science 10)

• Climate change: ___________________________________

_______________________________________________

_______________________________________________

These changes can affect the flow of ____________

energy over the entire Earth.

Several ice ages have occurred in the past million years.

Global warming: ______________________________

___________________________________________

___________________________________________

Both the causes and effects of global warming are

unknown and controversial.

THE ENHANCED GREENHOUSE EFFECT

The enhanced greenhouse effect: _________________

____________________________________________

____________________________________________

More greenhouse gases in the atmosphere =

________________ of natural greenhouse effect

5 examples of greenhouse gases include: ________

__________, _____, ________________, _________

________, and _____.

Global warming potential (GWP): __________________

____________________________________________

____________________________________________

CO2 is given a GWP of _____; methane is ______, nitrous

oxide is _______ and CFCs are __________________.

Carbon Dioxide and Methane

• CO2 levels have _____________ greatly in the past 200 years.

Since the _______________ _________________,

humans have greatly increased their overall use of

________ fuels, which release CO2 when burned.

Deforestation has changed carbon sinks, such as forests,

into carbon sources.

Many people are attempting to reduce CO2 emissions by

using _______________ energy sources or by

___________ their energy use.

Carbon offsets, such as wind farms, can be purchased to

offset CO2 emissions.

• Methane is very efficient at trapping thermal energy.

_____X more efficient than CO2

Methane is produced by _____________ breaking down

wastes in oxygen-free environments, ___________

digesting plant matter, rice paddies (and other natural

_____________ ), and the burning of ________ fuels.

Nitrous Oxide, Ozone, and Halocarbons

• Nitrous oxide, ______, is the ________ largest contributor to

the enhanced greenhouse effect.

Even though there are only small amounts, it has _____X

more GWP than CO2.

N2O comes from _____________, _____________,

and improper ____________ of human and animal waste.

• Ozone is an important ____ radiation blocker in the

stratosphere.

At _________ altitudes, however, it is a very powerful

greenhouse gas.

This ozone comes from ________ radiation

reacting with pollution from the burning of

_________ fuels, and is released from

photocopiers and certain ______ conditioners.

• Chlorofluorocarbons (CFCs) are the ________ reason for ozone

layer depletion.

They are ________-made greenhouse gases.

They are made up of ___________, ____________ and

___________.

Their main use is as coolants in ___________________

and _____ ________________ systems.

The _____________ atoms break apart ozone (O3) in

the atmosphere.

ALBEDO AND CLIMATE,

MAKING PREDICTIONS ABOUT CLIMATE CHANGE

• The albedo at Earth’s surface affects the amount of ________

radiation that region receives.

Changes in a region’s albedo could result in climate change

For example, large areas of Arctic sea ice

__________ would cause albedo in the Arctic to

_______, and _________ more solar radiation.

Some forests have _____ albedo which is believed

to play an important role in regulating climate.

THE ROLE OF SCIENCE IN UNDERSTANDING CLIMATE

CHANGE

• To increase the reliability of conclusions about climate change,

____________ measurements must be taken over ______

from around the ____________.

From these measurements, scientists have noticed

____________.

• Scientists use computers to model what Earth’s climate might

be like.

Although models differ, most indicate that a decrease in

the production of greenhouse gases is necessary to stop

the apparent global warming trend.

General circulation models (GCMs): _______________

__________________________________________

GCMs take into account changes in greenhouse

gases, albedo, ocean currents, winds and surface

temperatures.

GCMs are also used for weather forecasting,

climate analysis, and climate change predictions.

Scientists who use GCMs are always trying to

improve their understanding of climate and the

effects of human activities on it.

GCMs provide the best predictions of the future

conditions of our atmosphere and global climate.

THE ROLE OF INTERNATIONAL COOPERATION IN

CLIMATE CHANGE

• It is believed human-induced climate change is a ___________

occurrence.

The United Nations Environmental Programme (______)

and the World Meteorological Organization (______)

created the Intergovernmental Panel on Climate Change

(______) to address global concerns about climate

change and global warming.

The IPCC, formed in _______, has members from

____ countries.

The IPCC examines possible climate change,

highlights the causes, and suggests ___________.

The United Nations Framework Convention on Climate

Change (___________) created a voluntary treaty to

encourage governments to ___________ greenhouse gas

emissions.

GLOBAL IMPACTS OF CLIMATE CHANGE

• The IPCC suggests that lifestyle _________ and the use of

energy-_____________ technologies can reduce greenhouse

emissions.

Evidence shows that this will improve _____ _________.

IMPACTS OF CLIMATE CHANGE ON CANADA

• Being in the northern hemisphere, Canada could be strongly

affected by global warming.

Parts of southern Canada have had average

temperature increases of ____ºC to ____ºC, with

the greatest warming in the _______.

Temperatures are also increasing in the north.

• The Arctic regions are losing

___________ and Arctic Ocean ____

cover.

Growing seasons are getting ___________ and

______ precipitation is falling.

• There could be _________ spring rains

and severe ___________ in the future.

• __________ could be very negatively

affected.

• Pollution concerns could lead to

__________ issues.

IMPACTS OF CLIMATE CHANGE ON BC

• Most regions of British Columbia will probably be __________,

sea levels will ______, and fresh drinking water may be harder

to find as glaciers _______.

UNCERTAINTY AND DECISION, AN ACTION PLAN FOR THE

GLOBAL COMMUNITY

• Although climate change is a _________________ issue, our

actions _____ are important.

Improving our environmental approach will help, no matter

how dramatic climate change actually is.

Not acting could result in huge problems.

The United Nations suggests the ________________

______________, “better safe than sorry.”

CANADA’S RESPONSE TO CLIMATE CHANGE

• Relatively small changes could have large positive impact on the

climate in Canada.

_______ vehicle greenhouse gas emissions.

_______ industrial greenhouse gas emissions.

_________ use of energy-efficient products.

__________ indoor air quality.