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Natural Factors Affecting Earth’s Climate

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Presentation on theme: "Natural Factors Affecting Earth’s Climate"— Presentation transcript:

1 Natural Factors Affecting Earth’s Climate

2 Natural Events Affecting Climate
Earth’s climate is complex There are a number of factors that have affected our climate in the past and continue to do so today These are called Climate Forcings These include: Milanokovitch Cycles Sun Spots and Solar Flares Plate Tectonics Major Volcanic Eruptions El Nino and La Nina Forest Fires

3 Climate Forcings You've probably been "forced" to do a task by your parent or older sister: maybe it was homework, chores, practicing sports, or riding in the middle seat of the car. When you are forced to do something, it causes a certain outcome, or response, even if it is not right away. Brainstorm with the person sitting beside you about different ways you are “forced” to do things. For each example (Forcing) you think of, also Identify the change that will happen as a result of the forcing How long it will take the change to happen. From: BSCS Carbon Connections

4 Climate Forcings Copy the table below into your notebook
Add 4 more examples that you and your partner can up with. Forcing Response Lag Mom tells me, "Clean your room!" I clean my room. I do it 3 days later. Forcing: A forcing is any event or thing that causes or leads to change. Response: The response is the result or change from the forcing. Lag: The lag is how long after the forcing that the response starts to occur. From: BSCS Carbon Connections

5 Milankovitch Cycles Named after a Serbain mathematician,
Milutin Milankovitch EXTREMEMLY long term effects that scientists think may be the cause of the ice ages. These are movements of the Earth that affect the amount of solar radiation that it gets.

6 Milankovitch Cycles Earth’s wobble, tilt, and orbit Precession
Obliquity Eccentricity

7 Milankovitch Cycles Precession
Direction of the Earth’s axis changes over time The Earth wobbles like a top on its axis 26,000 year cycle

8 Milankovitch Cycles Obliquity
The tilt angle of the Earth’s axis changes over time The greater the tilt the greater the differences in the seasons. 40,000 year cycle

9 Milankovitch Cycles Eccentricity
Varying shape of Earth’s orbit, e.g. how elliptical it is 100,000 year long cycle Click on the “Animation” link for a hot link to the web. To get back to the Powerpoint presentation, look along the bottom toolbar and click on the powerpoint logo. Animation

10 Question #1 A Climate Forcing is:
what your mom says to make you clean your room. measured in degrees Celsius. the speed at which a change happens. an event or thing that causes a change. the amount of time it takes for a change to occur. Correct answer: D

11 Question #2 This term refers to the wobble of the Earth on its axis:
Perihelion Eccentricity Obliquity Aphelion Precession Correct answer is E.

12 Question #3 How would an increase in the tilt of the
Earth influence the seasons in Canada? Warmer summers and warmer winters Warmer summers and colder winters Colder summers and warmer winters Colder summers and colder winters A change in the tilt would NOT affect the seasons. Correct answer is: B

13 Solar Cycles Sunspots are storms on the surface of the sun and are associated with extremely strong magnetic activity, solar flares hot gaseous emissions These follow an 11 year cycle. Scientific research estimates that normal fluctuations due to Solar Cycles increase or decrease solar radiation reaching Earth by only 0.1% - 0.2%. Note that a prolonged period of virtually no sunspot activity as occurred during the 17th century can have a significant influence on Earth’s climate. The “Maunder Minimum” from is directly associated with the “Little Ice Age”

14 Images of the Sun’s changing surface activity
Modified from:

15 400 Years of Sunspot Activity
Modified from Note the period between on the graph  the “Little Ice Age” that students discovered with the Tree Core activity was thought to be at least partly due to very low sunspot activity. The figures show almost a complete cycle – 1980 – 1989.

16 Solar Cycles Rotating sun with sunspots You will now take a closer look Sunspots by graphing some data and analyzing the patterns in it. The animation at Windows to the Universe is nice. It may take a moment or two for the visual to load tho’. The activity should take about 10 min – all data/paper, etc. are in the handout.

17 The slide is the visual on page 4, for the Climate Discovery Activity attached to the lesson.

18 Question #4 A high number of Sun Spots, which indicate a large amount of storm activity on the surface of the sun result in a 2oC to 5oC increase in Earth’s temperature. result in a 2oC to 5oC decrease in Earth’s temperature. will have no effect on the Earth’s temperature. increase the solar radiation reaching the Earth by 10% Increase the solar radiation reaching the Earth by only a fraction of a %. Correct answer is E.

19 Question #5 The length of the Solar Cycles is 11 years 350 years
The correct answer is A.

20 Plate Tectonics Plate Tectonics and associated Continental drift
Have been exerting their effect on the Earth’s geography over billions of years Have shaped the continents as we know them The impact on climate (very long term, and in the past) was: by changing land mass and ice caps (size & location) and changing ocean circulation patterns which transport heat around the Earth and in turn influences atmospheric circulation processes. The hot link shows an animation of Plate Tectonics. A slower animation can be found at:

21 Volcanic Eruptions Volcanic eruptions of ash and gases into the troposphere and above cause SHORT TERM cooling (few years). The gases released are mainly water (H2O), carbon dioxide (CO2) and sulfur dioxide (SO2). The 1st 2 do not change ambient levels by much. But the SO2 reacts with H2O to form sulfates. Sulfates increase the brightness (albedo) of clouds, reducing the solar radiation reaching Earth. The large volumes of ash also block some incoming solar radiation but the effect is less significant and more short lived. An excellent web site for information on volcanoes and climate change is: Note: volcanoes release very little CO2 in comparison to human sources. The estimate of annual CO2 release by all volcanic activity is 130 – 440 megatons. This is dwarfed by annual human source emissions of about megatons.

22 Volcanic Eruptions Do Volcanic eruptions cause long term climate change? Apparently not. There is evidence of slight warming at some times, and slight cooling at other times. In these cases any temperature changes are minimal and short lived. Interesting point: During the time before and at the beginning of the Little Ice Age, there was an increased incidence of volcanic activity – enhancing the effect of the Sun Spot minimum. Cole-Dai, Jihong Volcanos and Climate. (Advanced Preview) In: WIREs Climate Change John Wiley & Sons Ltd., New York. 16 pages. Note – some scientists think that many millions of years ago there may have been periods of extreme volcanic activity caused by very active tectonic movements. It is possible that in these cases a more prolonged/significant impact on climate may have occurred.

23 Question #6 Continental Drift as a result of Plate Tectonics
is a major contribution to today’s climate change. affected Earth’s climate millions of years ago. impacted Earth’s climate by causing the ocean and atmospheric currents to change. Both A and C. Both B and C. Correct answer is E.

24 Question #7 Volcanic Eruptions
cause climate warming over a long term basis. cause temporary (few years) cooling of the Earth. only cause additional climate warming after the temperature recovers from the cooling period. cause long term (decades) cooling of the Earth. had nothing to do with the Little Ice Age. Correct answer is B.

25 El Niño/La Niña El Niño is a large scale change in oceanic and atmospheric circulation in the eastern equatorial Pacific and involves rapid, large scale warming of the sea-surface. Peruvian fishermen have noticed this because the warming is linked to a stop in the upwelling of deep nutrient-rich cold water just off their coast. During an El Niño event, this lack of nutrients reduces the productivity of the ocean and fish populations decline dramatically. La Niña is the opposite, a rapid cooling in this area.

26 El Niño/La Niña Transition between El Niño and La Niña O Observe the demo of El Niño (which will oscillate into La Niña). Observe it carefully & record 3 observations about what happens. (Check yourself – they should all be based on information you got from your senses.)

27 El Niño/La Niña Impacts: Tradewinds are weaker than average
Causing pools of warm water to move eastward across the ocean towards South America The cold upwelling water is reduced, the water warms (and levels rise) causing the fish to move away Warm waters produce lower air pressures, which increase convection, and increase rainfall – which can cause flooding. In tropical western Pacific (e.g. New Zealand) there is a slight decrease in ocean levels, lower convection and drought conditions

El Niño/La Niña El Niño and La Niña impact Canadian weather too! The La Niña that has been present since 2010 ended in April 2012. Scientists are predicting that El Niño conditions will likely start to develop this autumn. Use the map on the next page (from Environment Canada’s Project Atmosphere) to PREDICT OUR WINTER PRECIPITATION To update El Niño/La Niña conditions, go to: NOAA’s Climate Predication Centre at

29 Less snow.

30 Question #8 El Niño conditions
result in warmer surface waters off Peru. result in loss of fish in the waters off Peru. result in drought conditions in Australia. can cause flooding in western South America. all of the above. Correct answer is E.

31 Forest Fires Forest fires produce a lot of smoke – made up of particulates and gases. Based on what you learned about volcanic activity, what impact could large forest fires have on climate? -will this impact be local? Global? Forest fires can cause local temporary cooling - but to a much smaller degree than Volcanic activity. Large volcanoes send ash and more significantly gases (including sulfur compounds) very high into the atmosphere where they can be influenced by high altitude winds and circulate on a global scale. Forest fires, in contrast, produce little sulfur emissions and the smoke typically remains at low altitudes. The ash usually remains relatively local and is “washed out” quickly. Note also that forest fires increase when drought conditions and warmer temperatures occur. So, unlike volcanoes the actual frequency and severity of forest fires responds to climate change! Hmmm…. Chicken or the egg?

32 Virtual Simulation You are now going to look at the impacts of El Niño
activity, Volcanic aerosols and Sunspots. Go to Carbon Connections Find Activity 3.2, “Testing Forcings” Click on the figure “Climate Model” to open it. Follow the instructions and answer the questions that follow each section. Order: El Nino/La Nino, Volcanic Aerosols, Solar Cycles This will take 20 min – 30 min for SNC2D (depending how long it takes to get organized). Time will be about 30 min and may be adjusted for SNC2P courses.

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