2 Causes of Climate Latitude – differential heating Topographic effects –Proximity to waterAltitudeMountain rangeAir Masses
3 Climatic ChangesClimate change is a slow process but has occurred multiple times in earth’s historyEx) Multiple ice ages – periods of cooler climate and extensive glaciers
4 Short-term climatic changes Ice ages are an example of long-term climate changeSeasons- an example of short-term climate change
5 Seasons What causes them? The tilt of the earth on its axis. Seasons are NOT caused by distance from the sun.The hemisphere tilted toward the sun receives more direct radiation. How does this affect intensity?
6 El NinoClimate changes due to reversing of an ocean current in the Pacific Ocean.Basically, El Nino can flip climate conditions in many areas.
7 Natural Climate Change Climate changes have occurred throughout earth’s historyCan be caused by changes in solar activity, earth’s tilt, and volcanic eruptions
8 1. Solar activityRelationship between low sunspot activity and colder climates on earth.Maunder Minimum – low sunspot activity period
9 2a. Earth’s orbitEarth’s orbit cycles between circular and elliptical every 100,000 years.A more elliptical orbit = warmer climate because earth is closer to the sun.
10 2b. Earth’s tiltCurrently the earth has a 23.5 degree tilt on its axis. Seasons are caused by the tilt changing throughout the year.The angle varies from 22.1º to 24.5º every 41,000 years.Less angle = seasons not as drastic
11 3. Earth’s wobbleThe axis of the earth points to a different point every years.Switches cause summer and winter to be more drastic.
12 4. Volcanic activityBig eruptions send a massive amount of dust in the atmosphere. It can remain suspended for years blocking solar radiation.Cause cooler climate periodsShort term climate change
13 Human FactorGreenhouse effect – natural heating of earth’s surface caused by certain atmospheric gases (water vapor, carbon dioxide).The gases trap heat that is radiated by the earth.It is NOT a human invention.
14 Greenhouse effectIt may be possible to increase or decrease the greenhouse effect by changing the amount of greenhouse gases (CO2)This is the current controversy
15 Global WarmingTemps have warmed over the last 200 yrs (scientists agree)Could eventually cause ice caps to melt, coastal flooding, deserts to spread, and more severe storms
16 Global Warming, pg 376!!! Scientists agree that temps are climbing Do not all agree about whyNatural causes vs. increased CO2 in the atmosphere (artificial or human influences)
17 Increase of carbon dioxide Burning of fossil fuelsDeforestationDon’t waste electricity! Recycle!
18 Renewable vs. Nonrenewable Renewable energy sources – energy from resources that are continually replenishedExamples?Nonrenewable energy sources – take thousands of years to form. Cannot be replaced as quickly as they are usedCompare and contrast benefits?