SNC2P Climate Change Notes ANSWER KEY

Weather and Climate

Weather: the daily conditions of our atmosphere

Includes temperature and wind, precipitation and humidity.

Weather is produced by a number of factors

Heat – Absorbed from the Sun.

Air pressure – Measure of force of air pressing down on the Earth.

Winds – Created by a difference in air pressure.

Moisture – Precipitation in the form of rain, snow, sleet, or hail.

Climate is the average Weather conditions in a specific region over a long time.

Climate is based on average temperature and precipitation patterns.

The Earth has three major climate zones

Tropics between the Tropic of Cancer and the Tropic of Capricorn

Temperate between the Tropics and the Arctic or Antarctic circles

Polar above the Arctic Circle or below the Antarctic Circle

SNC2P Climate Change Notes ANSWER KEY

The Climate Zones of the Earth are identified by the precipitation, temperature, and types of plants that grow there.

In Canada there are a number of different climate zones, but most of Canada is the humid subarctic zone. Here in Perth, we are in the humid continental zone, which means that we have a warm summer with a lot of humidity, and cold winters with a lot of snow.

SNC2P Climate Change Notes ANSWER KEY

Evidence of Climate Change

Scientists have been collecting data on global temperature since 1880. You will notice that there have been lots of changes in temperature, but the data since 1980 shows a trend upward at a faster rate than in the last 150 years all together.

Scientists look at other evidence to find out about weather patterns older than our data goes back. We know from fossils that there have been times when the climate of the Earth was very different.

When the dinosaurs roamed the Earth, the Jurassic Age climate was hot and humid. (Very tropical)

At other times, most of the Earth was covered in ice like during the Carboniferous age.

SNC2P Climate Change Notes ANSWER KEY

Scientists often look to the past to help them understand today’s climate. By identifying how and when Earth’s climate changed in the past, they gain a better understanding of how today’s climate responds to change. The best sources of information about past climate are trees, ice cores, and fossils.

Tree rings can provide data on years of good growth, or poor growth, which indicates years of warm weather and plenty of rain.

Ice Cores

Permanent ice fields in the Artic and Antactic have existed for hundreds of thousands of years. Each year, another layer of ice has been added. Each layer of ice details the conditions of the area at that time. Ash indicates that volcanoes erupted. Pollen trapped in the ice indicates the type of plants nearby. Air bubbles caught in the ice detail amount of oxygen and carbon dioxide in the atmosphere.

This ice core data indicates that CO2 concentration is linked to temperature. As the temperature of the atmosphere goes up, so does the CO2 concentration in the atmosphere.

Scientists now collect data using weather balloons and satellites. They use this data to create

models of what is happening now and what could happen in the future.

SNC2P Climate Change Notes ANSWER KEY

Natural Factors that Affect the Earth’s Climate

The Earth is heated by solar energy – energy from the sun. However, not all regions of the Earth receive the same amount of solar energy. Two main factors are Latitude and the Earth’s Tilt.

Latitude:

The equator has latitude of ZERO, which is the place that receives the most constant direct sunlight on Earth. We live at a latitude of 43 degrees, which means that when we gets solar energy from the sun, the rays are more spread out, thus resulting in the cooler weather we experience relative to those who live at the equator.

Earth’s Tilt:

The Earth does not stand straight up/down, it

actually has a tilt of about 23.5˚, although it is

said to vary from 22.1° to 24.5°, which

scientists believe contributes to the natural

climate patterns that are observed.

During our summers, the North Pole tilts in

towards the SUN, which causes for more

direct solar energy, resulting in the warmer weather we experience.

SNC2P Climate Change Notes ANSWER KEY

Natural Energy Balance:

As the solar energy reaches Earth, it has two options

Absorption OR Reflection.

Some energy is reflected immediately by the atmosphere (6%), clouds (20%) and the ground’s surface (percent depends on the type of surface).

The proportion of incoming sun rays that are reflected by a surface is called its ALBEDO

Rank the surfaces below in the order of which you think reflects most to least:

snow/ice (1) forests (5) clouds (2) crops (4) desert (3) water (6)

85% 10 – 20% 40 – 70% 18 – 25% 20 – 40% 3 – 10%

Snow/ice clouds desert crops forests water

Changes in the albedo of a region can cause the Earth’s temperatures to change. For example, people are worried about the polar ice caps melting because:

Melting extra water and land exposed absorbs more energy than the ice previously did, thus causing the Earth’s temperatures to increase more, which in turn melts more ice!

The opposite can also be true if a volcano explodes and throws a lot of ash and debris into the air.

Debris reflects a larger amount of sun energy which causes the temperature to decrease, which in turn can cause increased ice and snow which ultimately reflects more sun energy and thus cools the overall climate.

Green House Effect

Most of the solar radiation that comes from the SUN

travels through our atmosphere and 51% gets

absorbed by the Earth. Some of the short wave

radiation is reflected back into space by the

atmosphere.

The short wave radiation UV passes through the atmosphere and gets absorbed by the ground. Some of this energy is re-emitted back into the atmosphere,

but as much longer radiation- now in the infra-red wavelength. Many of these wavelengths are reflected back to the Earth’s surface by the gases in the atmosphere. This warms the surface of the Earth. This is known as the

SNC2P Climate Change Notes ANSWER KEY

GREENHOUSE effect. Without the greenhouse effect, the Earth’s surface would be about -18°C! Our problem is that humans are producing more of these greenhouse gases which affects the amount of RADIATION reflected back to the surface of the Earth. This human caused increase in the greenhouse gases is called the ANTHROPOGENIC GREENHOUSE EFFECT.

Type Sources Issues associated with themCarbon Dioxide Natural:

Forest FiresVolcanic explosionsBreathing

Human ActivitiesFactoriesCars/trucks/etc…Burning fossil fuelsDeforestation

Before the industrial age, CO2 used to be at 280 ppm (parts per million), where as today, they are reaching levels of around 385 ppm (0.0385%)

Water vapour H2O in the atmosphere Under regular conditions, water vapour cools and returns to the Earth as precipitation. However, as the Earth’s temperatures rise, more water vapour is created thus trapping more energy which will again cause more water vapour , etc...

Methane Gas Natural:Animal digestionDecomposition of plants

Human Activities:Landfills and sewage treatmentIncreased meat consumption (more animals)Extraction of fossil fuels

20 times more effective as a greenhouse gas – meaning traps more of the radiated energy

Increased global temperatures are releasing the methane gas trapped in the permafrost

Nitrous Oxide Natural:Breakdown of nitrogen compounds in soils by bacteria

Human Activities:FertilizersIncreased animal wasteBurning fossil fuels

300 times more effective than CO2 at trapping radiated energy

Effects of Climate Change

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Oceans: The oceans of the Earth cover 71% of the surface of the Earth. They absorb heat from the sun. Warm water is less dense, so it rises to the top, while cold water is more dense and sinks to the bottom. Salty water is more dense, and sinks, whereas less salty water rises to the surface. This movement produces ocean currents.

This moving water carries heat around the whole world, and influences air currents.

As the global temperature rises, the oceans become warmer. Warmer water cannot contain as much oxygen, so this affects the aquatic life forms.

Oceans absorb carbon dioxide from the atmosphere, so act as carbon sinks (removing large amounts of CO2 from the atmosphere). As the amount of CO2 in the atmosphere increases, the amount absorbed by the ocean increases as well. An excess of CO2 in the water creates carbonic acid. This leads to much higher levels of ACIDITY in the ocean, which has serious consequences for marine life.

Coral reefs are dying. These coral form the habitat for a variety of aquatic life.

SNC2P Climate Change Notes ANSWER KEY

Melting Glaciers: The permanent ice in the Artic and ANTARTIC is melting due to warmer temperatures around the globe.

Notice the shrinking of the polar ice from 1979 to 2010.

Remember that ice reflects more of the sun, so as the ice melts, more water is exposed, which absorbs more HEAT which increases the rate of MELTING.

The animals in the polar region that travel over the permanent ice to hunt for food, are having more problems surviving with less permanent ice.

The glaciers in Canada are an important source of WATER for many western provinces. As the glaciers melt, there is less water in the summertime, which leads to more DROUGHT.

SNC2P Climate Change Notes ANSWER KEY

Rising Sea Levels

Sea levels are RISING. Partly due to warmer water which expands, but also due to our GLACIERS melting. How does this affect our lives?

Rising sea levels lead to FLOODS. The main concern is that in most countries, large urban areas are on the coastal regions. With a rise in sea level, cities will be flooded- places like VANCOUVER, NEW YORK, TOKYO are all in danger of being flooded if the sea rises significantly.

Rising sea levels would also destroy habitat for animals, and damage fisheries.

Extreme Weather

Most people think that climate change is just Global warming, but it is much more than that. As the global temperature rises, the climate changes, with more extreme weather events: more HEAT and less rain in the hot climates, but more storms in other places. We have seen this in the last few years, with devastating FLOODS and hurricanes.

These extreme weather events cause billions of dollars in damage, have huge economic impacts and cause loss of life.