Climate Changes Section 3, Chapter 12 pg. 362

Seasons Reasons Seasons are short-term climate changes. Discuss with your table the climate of two seasons. Write a brief paragraph about that shows how they contrast.

Earth Seasons Figure 8 pg. 362 What causes seasons? During which northern hemisphere season is the Earth closer to the Sun? winter

High Latitudes pg. 363 High latitudes have greater variation in temperature and number of day light hours Equator the days are about the same length all year long.

Landslides and More: El Nino I. El Nino pg. 363 A. Involves the tropical Pacific Ocean and the atmosphere. B. Involves the trade winds not blowing as hard causing warm tropical water in the Pacific to flow back eastward to South America Cold water is forced up off the west coast of South America..during normal years.. As winds blow east to to west. Peru: El Nino is Spanish for the Christ Child named because it usually appears near Christmas. Fish become less abundant during El Nino so fisherman use this time to repair equipment and spend time with their families. Why are there fewer fish during El Nino? Upwelling of nutrients stops or is greatly reduced. Less upwelling means less food for fish.

El Nino pg. 363 C. Effects weather patterns D. Effects or alters the jet stream F. Effects atmospheric pressure in California G. Effects wind and precipitation around the world. H. Can cause drought in Australia & Africa I. Can cause storms in California and monsoon rains in Indonesia

Opposite of El Nino pg. 363 I. La Nina Winds blowing across Pacific are stronger than normal B. Causes more water accummulating in the western Pacific

La Nina pg. 363 C. Eastern Pacific water is cooler than normal D. Causes droughts in southern U.S.A. E. Causes excess rain in the NW U.S.A. Figure 10 , pg. 364-365,shows the differences in these two systems. Pay attention to the maps on page 365. And in content background on same page. Scientists are not sure what causes El Nino. Cold water normally brings about large amounts of nutrients through upwelling. Primary producers live on these nutrients thrive in this area, providing a large base for the food web. Fish , birds, marine mammals depend on these primary producers. If these does not happen the number of producers decrease and greater numbers of consumers face starvation

Climate Change Is it possible to prepare for short-term climate changes caused by catastrophic events like meteorite collisions or volcanic eruptions? No-we can’t predict when these events will happen Yes- we can prepare for the possible effects if they do occur Climate has changed many times during Earth’s history and that although scientists once thought that climatic changes always took a long time to happen, new evidence suggests that some climatic changes occur over short periods of time.

I.Fossil evidence indicates climate change Climate Change pg. 366 I.Fossil evidence indicates climate change A. Warm weather plant and animal fossils are found in cold climates B. Sediments show that many parts of the world were covered by large glaciers-called ice ages Climate has changed many times during Earth’s history. New evidence supports that climatic changes occur over shorter periods of times than previously thought. Evidence in Ice Cores that cover the history over 300,000 years.

Interglacial periods last 10,000 to 15,000 years Climate Changes pg.366 C. Ice ages have alternated between warmer periods called interglacial intervals. D.Ice ages last 60,000 to 100,00 years Interglacial periods last 10,000 to 15,000 years E. We have been in an interglacial period for 11,500 years

Climate Change pg. 366 E. We have been in an interglacial period for 11,500 years F. Ice cores tell that the last ice age lasted only 1,000-2,000 Evidence from the ice cores studied from Greenland Ice cores are like tree rings, Major ice ages occurred 2 billion, 650 million, 250 million, and 3 million to 10, 000 years ago. In the most recent ice age, the ice sheet in some places was 3,000 meters thick.

What causes climatic changes? Pg. 366 I. Change over short periods of time are caused by: A. Catastrophic events 1. Meteorite collisions 2. Volcanic eruptions B. Solar output Solar can also be long term effect.

II. Change over long periods of time are caused by A. Solar output Pg. 367 II. Change over long periods of time are caused by A. Solar output B. Changes in Earth’s movement in space C. Plate tectonics

Mt. Pinatubo pg. 367 figure 12 In 1991 particles wer spread high into the atmosphere blocking some the Sun’s energy that could result in cooling the planet.

Atmospheric Solids and Liquids pg. 367 I. Particles enter the atmosphere by A. Volcanic eruptions B. Soot from fires C. Soil particles carried by wind D. Industrial pollution E. Meteorite collisions II. Particles block Sun radiation, cooling the planet.

I.Solar radiation can vary A. Sunspots Energy from the Sun pg. 367 I.Solar radiation can vary A. Sunspots B. Evidence supports a link between sunspots and climate C. Fewer sunspots, colder climate Cold period in Europe between 1645-1715.. When there were few sunspots on the Sun

Earth’s Movement pg. 368 I. Hypothesis that change in tilt will cause climate change A. Earth’s wobble B. Earth’s orbit changes 1. Sometime more circular 2. Sometimes more flattened Tilt changes every 41,000 years. Has increased and decreased.. 24.5˚ to 21.5˚.. This would change the amount of radiation the Earth receives in specific areas. Wobbles as its spin is slowing very gradually Earth’s orbit changes over a 100,000 cycle

Amount of Solar Radiation pg. 368 Movements of Earth effect amounts of solar radiation reaching different parts of Earth. Explains how glaciers grow and shrink but not rare occurances …over geological time.

Energy from the Sun figure 13 pg 368

Crustal Plate Movement pg. 368 I. Movement of continents and oceans affect the transfer of heat on Earth A. Affects wind and precipitation patterns II. Growth of Himalayas change climate over much of Earth Himalayas growth over 40 million years ago

Climatic Changes Today pg. 369 I. Greenhouse effect could be responsible for some present day global warming A. Natural greenhouse gases in Earth’s atmosphere 1. Water vapor, carbon dioxide, methane B. Without these, life would not be possible on Earth. Without gases we would be like Mars.. Too cold IF too strong, we would be too warm.. Like Venus

Greenhouse Effect pg 369 An extreme example of the greenhouse effect at work has been observed on Venus. Boiling-hot temperatures are common on the planet’s surface both at night and during the day. Venus’s atmosphere is dense with carbon dioxide, a greenhouse gas that traps heat around the planet.

Global Warming pg. 370 Average global surface temperatures have increased by about 0.6˚C Atmospheric carbon dioxide has increased by 20% Do lab demonstration. Page 370. Materials: Phenol red, candle, match, petri dish, tall, narrow jar, clay What causes color change? (presence of carbon dioxide) What was the source of carbon dioxide? (Carbon from the burning candle combined with oxygen to form C02) Why was the second petri dish used? (as a control)

If… pg. 370 If temperature continue to rise Glaciers would melt Low lying coastal areas would flood Organisms would have to adapt or die In some tropical waters, coral reefs are dying because of a warmer planet

Pg. 370 Climate models show Earth’s temperature will increase faster than before Uncertainties exist in climate models and in estimating future increases in atmospheric C02 Figure 15 on page 370.. Glacier in Greenland

Human Activities pg. 371 Things that affect the air in our atmosphere: Burning fossil fuels a. Natural gas, oil, and coal 2. Deforestation a. cutting down trees b. burning trees

The Carbon Cycle figure 17 pg.372 What can humans do to slow down carbon dioxide increase in the atmosphere? (Reducing the use of fossil fuels, reducing deforestation, etc)

The Carbon Cycle I. Carbon is constantly recycled among A. Atmosphere B. Earth’s oceans C. Land organisms

Atmosphere Organisms undergo photosynthesis on land Organisms use CO2 to produce and store carbon based food Food is eaten by consumers. Food is broken down to respirate.

Organisms die and decay Carbon is stored as humus in soil Some Carbon is released as CO2 Some CO2 gets dissolved in oceans Used by algae and other organisms Those organisms give off CO2 Earth’s oceans are absorbing more CO2 from the atmosphere than they give off.. Warming contributes to this.

Forecasting Climate Consider Why do some scientists not agree on their forecasts for Earth’s Climate? Students should discuss the MANY variables that must be considered in making such predictions.

Assessment Contrast the affects of volcanic aerosols and CO2 atmospheric temperature Volcanic aersols reflect solar energy making Earth cooler. CO2 traps heat making Earth warmer.