GEOG 2300 1st Edition Lecture 13Outline of Last Lecture I. Climate ChangeII. Weather and ClimateOutline of Current Lecture I. PaleoclimateII. Paleoclimate ToolsIII. Greenhouse EffectCurrent LectureI. PaleoclimateA. In the past million years, temperature fluctuates, but is around 12 degrees C + or – 6 degreesB. 11,000 to 13,000 years ago – ice age C. Holocene : epoch after last ice age, ice age in PleistoceneD. Late 1400’s in Europe – the black death (bubonic plague), cold, wet, lots of deathsE. Denver and Washington D.C. - which statement is correct? Denver would have more diurnal temperature variation (diurnal temperatures vary more when you’re inland and as elevation increases)F. Scientists study the paleoclimate by analyzing air bubbles trapped in ice cores; tells scientists about troposphere composition, temperature trends, greenhouse gas concentrations, solar and snowfall and forest fire activityG. In 2005, an ice core showed that CO2 levels in the troposphere are the highest they have been in 650,000 yearsH. Carbon dioxide has a direct relationship to temperatureI. Using the past carbon dioxide levels we can model what the carbon dioxide levels may be in the futureII. Paleoclimate ToolsA. Ice cores: trapped bubbles of air from the past that can determine atmospheric condition, date isotopically or through counting layersB. Tree rings: count rings to determine ages and ring size tells us about the climate that yearThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.C. Pollen studies: counting different types of pollen in sediment cores of lakes and wetlands tells us about local plants through time, time is determined from carbon dating and layer countingD. Charcoal: great tool for carbon dating that tells the age the layer of charcoal is inE. Middens: people and animals leave trash behind and over the ages this buildsup, trash can be carbon dated and its composition tells what was aroundF. Cosmogenic dating: cosmic rays cause changes in exposed sediment, but shutoff when the sediment is buriedIII. Greenhouse EffectA. Three major factors shape earth’s climate: the sun, the greenhouse effect, movement of heat in oceansB. Enhanced greenhouse effect causes global climate changeC. Global energy balance: balance of incoming and outgoing radiative energy in the earth-atmosphere systemD. Climate change: any change in the climate over time due to natural or humaninfluencesE. Radiative forcing: influence a factor has on changing the global energy
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