How do we know about the climate 150,000 years ago?

How do we know about the climate 150,000 years ago?

Are they using time machines?

Are scientists making stuff up?Climate data of the pastActual Measurements

Humans have been recording climate using instruments for only the past ~100-200 years

Instruments to record temperature, wind, precipitation, etcClimate data of the pastHistorical RecordsOld journals describing natural disastersAgricultural records, for example when grapes were harvestedOld records of when different plants were in bloomVoyage records

Bradley, R.S., 1991. Pre-instrumental climate: how has climate varied during the past 500 years?Garcia et al. Manila Galleons Voyage RecordsClimate data of the pastProxiesPaleoclimatologists use paleoclimate proxies.

proxy: An indicator of past climate. A proxy (meaning substitute) is an indirect measure of climate, as opposed to direct measures such as reading temperature from a thermometer.Just as Sherlock Holmes might infer the height, weight, and other telltale features of a suspect from a series of footprints, paleoclimatologists infer the climatic conditions of the past from tree rings, ice cores, layers of ocean sediments, fossils, and similar proxy evidence.

Introduction to proxy data videoShow introduction only5

6Span and ResolutionSpan = how far into the past the proxy information goes

Resolution = how specific the climate information is in terms of years

A higher resolution ca n give you information about a specific year.A lower resolution will show long-term changes that occur over many years. Resolution = how "fine-grained", in terms of time spans, the climate information is, and thus to what extent we can detect short-term or sudden changes in climate. Emphasize estimation and inference involved in different methods

7Span and Resolution of Proxy Sources

Point out different spans 8

Time Limits of Various Proxy Data(years past)Where does proxy sampling occur?location of proxy dataIce CoresJim White: Stable Isotope Lab @ CU

http://michigantoday.umich.edu/2009/11/vostok-graph.jpg

Tree Rings

http://www.ncdc.noaa.gov/paleo/ctl/images/16thchron2.jpg

http://saima-tutkimus.fi/saimapictures/kiekkoisov.jpg

http://www.ncdc.noaa.gov/paleo/pubs/smith2006/fig1.jpg

http://www.windows2universe.org/earth/climate/images/stalagmites_sm.jpgSpeleothems

http://upload.wikimedia.org/wikipedia/en/a/a1/Labeled_speleothems.jpg

Pollen

http://lh5.ggpht.com/_j1cdMMQnYns/TMLGrbaJP_I/AAAAAAAAJMU/2CNdQce5DKw/lavender-pollen-grain--lavandula-dentata--80200172-m%5B4%5D.jpgCanadian modelHadley model

Coral

bleachinghttp://switchboard.nrdc.org/blogs/fbeinecke/Bleached.coral.jpg

http://www.climateshifts.org/wp-content/uploads/2011/02/Bellwood-et-al-Fig-1.jpgAs temperatures increase the corals bleach and dye off.Additionally, the increase in sea temperatures will cause sea levels to rise decreasing photosynthesis.15Historical

16Conclusion

http://scienceinthetriangle.org/wp-content/uploads/2011/02/spaghetti-climate-graph.jpgCombining all of the proxy dataDiscuss how the multiple proxy variables are use to generate one general consensus on global climate.17Proxy data sourceDescription of how it is collectedWhere is it collected?How far back does it go? (span)Resolution1Tree Rings2Corals3Packrat Middens4Lake and Ocean Sediments5aPollen in lake sediments5bFossils6Ice CoresStation 1 Dendochronology (Tree Rings)Read the background information on tree rings. (see printed text)Then click on the link below, You be the Dendochronologist and practice making different width rings and matching exising data. Follow the instructions on the page.Complete your chart.You be the dendochronologistThis station requires at least one computer per 2 students.19Station 2 - Coralscoral video Read the text and watch the video. Click on coral video to link to the page.

2. Watch a short video (no sound) to see how the coral cores are collected.

3. Complete your chartcoral core collection (no sound)This station requires a computer and headphones or have students separated from other groups. Could combine stations 3 and 4 to balance time with other stations.20How we measure past sea level from corals

Acropora palmata is a coral that only grows in water that is less than 5 meters deep.Therefore if it is found in a location, you can infer that that location was once under 5 meters or less of water.Acropora palmata coralScientist drilling for coralStations 3 - Packrat MiddensPackrat Middens Packrats, as their name implies, constantly collect all kinds of materials from their surroundings. Their collections, called "middens", provide clues to the past climates of the region. Packrat middens are clumps of vegetation, insects, remains of vertebrates, and other materials cemented together by crystallized packrat urine (referred to as amberat). These rock-hard deposits can be more than 20,000 years old.

Packrat making a middenSource: San Diego Natural History Museum A scientist examines a packrat midden.Credit:W.G. Spaulding and National Oceanic and Atmospheric Administration Paleoclimatology Program/Department of Commerce

A sample of packrat midden from Red Creek (RC2) that dates to 3320 B.P. Needles of lodgepole pine were recovered from this midden found in the lower basin. Packrat MiddensPrint text for students in color22Station 4 Lake and Ocean SedimentsLake Sediment proxy data video and text1. Watch the video and read the text. Click on the lake sediment proxy link to view the video.2. Complete your chart.

more information and pictures on lake sedimentsCollecting a lake sediment coreThis station requires a computer. http://eo.ucar.edu/staff/rrussell/climate/paleoclimate/sediment_proxy_records.html23Station 5Lake Sediments and Pollen

See text in lesson plan. 24Station 6 Ice CoresComplete this the next day or just give them span and resolution.25Debrief Which proxy data would be appropriate for determining climate 1.5 million years ago?Which proxy data would be appropriate for determining the climate around Hawaii?If you were wondering if there was an ocean in Colorado, which type of proxy data would be appropriate?Looking at your graphs, which type of proxies might have been used and why?In your journal, explain to a skeptic: How scientists know about the climate of the past.1-3 could be verbal in small groups. 4 could be verbal whole class and 5 reflection in journal. 26Ice: Its more than just frozen water

What Can Ice Cores Tell us about Past Climate?Jim White short version video of ice cores

IntroductionBackgroundEarths climate changes. Although there is debate over what causes this change, scientists agree that Earths climate has changed and continues to change over time. One way to learn about these changes is through the study of glacial ice cores. Ice cores create a layered historical record of the climate over time. Scientists drill deeper into older layers of ice; sometimes to a depth of over 3,500 meters (2.2 miles).By performing physical and chemical tests on ice cores, scientists can create a snapshot of the Earth at single points in time. Atmospheric gases, from hundreds to thousands of years ago, are trapped as small bubbles within the ice. Measurements of gases, including carbon dioxide, paint a picture of the atmosphere at the time the gases were trapped. How are they collected?

Figure 1. Ice Core Sampling. Image credit: Reto Stckii, NASA GSFCNASA lesson, mention that it takes a whole team and several companies29

An ice core sectionWhere are they collected?map of drilling sites31Side view showing dust & ash layers(from drought years and volcanoes)

Melting a core sampleto release the trapped gases