Climatic ChangesClimatic Changes

During an average During an average human lifetime, human lifetime, Climates do not Climates do not

appear to change.appear to change.However, they are However, they are in a constant state in a constant state

of changeof change

Long Term Long Term Climatic ChangesClimatic Changes

Ice AgesIce AgesInterglacial IntervalsInterglacial Intervals

Ice AgesIce Ages- period of - period of

extensive glacial extensive glacial coverage. There coverage. There

have been several have been several glacial advances glacial advances

and retreatsand retreats

Interglacial Interglacial IntervalsIntervals- Warm - Warm periods periods between between

glaciationglaciation

Short TermShort TermClimatic ChangesClimatic Changes

SeasonsSeasonsEl NinoEl Nino

SeasonsSeasons- regular - regular

variations in variations in daylight, daylight,

temperature, and temperature, and weather patternsweather patterns

El NinoEl Nino- Weakening of the - Weakening of the equatorial current equatorial current

brings warmer brings warmer waters to the west waters to the west

coast of coast of South AmericaSouth America

Evidences of Evidences of Climatic ChangeClimatic Change

- Tree Rings- Tree Rings- Ice Core - Ice Core SamplesSamples- Fossils- Fossils- Radio Carbon - Radio Carbon SamplesSamples

Causes for Causes for ChangeChange

Human Human ActivityActivity

- Pollution may - Pollution may aid global aid global warmingwarming

Volcanic Volcanic ActivityActivity

- Dust blocks - Dust blocks solar radiation solar radiation

lowering lowering global global

temperaturestemperatures

Solar ActivitySolar Activity- increased solar - increased solar activity causes activity causes

increased global increased global temps. 11yr cycletemps. 11yr cycle

Earth’s OrbitEarth’s Orbit- More circular - More circular orbit = cooler orbit = cooler global temps.global temps.

100,000 yr 100,000 yr cyclecycle

Earth’s Earth’s WobbleWobble

- Reversal of - Reversal of Earth’s Tilt Earth’s Tilt reverses reverses seasons.seasons.26,000 yr 26,000 yr

cyclecycle