14.3 Climatic Changes SWBAT distinguish among different types of climatic changes; recognize why climatic changes occur.

Ice Ages  Ice age Extensive glacial coverage over earth  Average temperatures decrease by 5°C

Short Term Climatic Changes  Seasons Short term periods of climatic change caused by regular variation in:  Daylight  Temperature  Weather patterns Result of change in solar radiation

Short Term Climatic Changes  El Niño A warm ocean current that occasionally develops off the western coast of South America  Scientists still don’t know what causes this

Change Can be Natural  Solar activity E.W. Maunder found sunspot activity was related to climate Maunder minimum  Period between 1945 to 1716 where there was low sunspot activity  Correlated to a “little ice age” Below average temps Bitterly cold winters High periods of sunspot activity = higher temps Low periods of sunspot activity = lower temps

Change can be Natural  Earth’s orbit Earth’s elliptical orbit changes slightly over time, varying between circular and elliptical (ovular)  Elliptical – when it’s closer the sun temperatures are warmer  Circular – when it’s further from the sun temperatues are colder

Change can be Natural  Earth’s axis Earth tilts at an angle of 23.5° This tilt can vary between 22.1° and 24.5°  Change in angle can make seasons more severe

Change can be Natural  Earth’s wobble Earth wobbles as it spins on its axis  This causes warmer summers and colder winters

Change can be Natural  Volcanic Activity Volcanic ash is suspended in the air for several years  This blocks solar radiation  This lowers temperatures

With a Partner  Answer questions 1-6 on page 374  Answer in complete sentences  Finish for homework