Transcript Figure 4
Long-term climate change & Short-term climate variability Climate is the average weather pattern for an area over a period of time It is determined by Rainfall & Temperature which are influenced by Latitude Elevation Ocean Currents & affects where people live how people live what they grow & eat Based on http://www.fsl.noaa.gov/~osborn/CG_Figure_10.gif.html Since the last ice age GISP2 stable isotope record Younger Dryas – snow accumulation Temperature last 11,000 years Arctic temperatures 6000 years B.P. Historical perspective Awareness of climate variability for thousands of years: e.g. their local histories & folklore. – Levels of yearly Nile flood levels recorded as early as 3000 B.C. – Egyptian tombs have written records & pictures of years of drought & famine – Climatic catastrophes such as floods occur in numerous accounts Early scientific writings Aristotle (384-322 B.C.) first wrote on climate change in a critical manner: " The same parts of the Earth are not always moist or dry, but they change according as rivers come into existence or dry up. And so the relation of land to sea changes too, and a place does not always remain land or sea throughout all time.... But we must suppose these changes to follow some order and cycle." From: http://www.carleton.ca/~tpatters/teaching/climatechange/climateawareness/aware15.html Early scientific writings Pliny the Elder (A.D. 23-79) stated in his Natural History Book XVI, 15, that the beech tree (fagus), which he regarded as a mountain tree that descended to the plain in northern Italy, formerly grew within the precincts of Rome itself but did so no longer in his day. " The climate was now too hot there, as it was also for chestnut trees." From: http://www.carleton.ca/~tpatters/teaching/climatechange/climateawareness/aware16.html Early scientific writings Chin Li-Hsiang (A.D. 1252-1303) studied evidence of the pattern of cultivation in China during the Chou, Chin & two Han dynasties (900 B.C. - A.D. 220) & determined that the climate then had been rather warmer than in his own time From: http://www.carleton.ca/~tpatters/teaching/climatechange/climateawareness/aware16.html Northern Hemisphere temperature Mann et al., 1999 5 major phases in Northern Hemisphere in last 1400 years The medieval climatic optimum Also called “Europen Warm Period” “Little Climatic Optimum” 700 – 1200 AD Timeline 874 Settlement of Iceland begins 930 >25,000 people living in Iceland 935 Settlement of Greenland begins 1020-1200 Minimal sea ice cover around Iceland 1080-1180 Mild winters, dry summers 1100 70,000 people in Iceland 5 major phases in the Northern Hemisphere in last 1400 years Medieval Glaciation 1200-1460 AD Timeline Late 1100’s Sharp decrease in Camp Century (Greenland) ice-core 18O content signals lower temperature in North Atlantic region 1200 Increased sea ice in coastal water of Iceland 1200’s Glaciers advance into Iceland & Europe Timeline 1300’s Decline of vineyard in Germany; loss of vineyard in England By 1350 Fishing replaces cereal crops as main food resource in Iceland By 1350 Western settlement in Greenland found abandoned 1410 Last reliable account of Norsemen in Greenland 5 major phases in the Northern Hemisphere in last 1400 years Brief climatic improvement 1460 – 1560 AD 5 major phases in the Northern Hemisphere in last 1400 years Little Ice Age 1560 – 1890 AD Timeline 1600 Eruption of Huaynaputina volcano (Peru) causes severe short-term cooling 1600 Dramatic increase in sea ice in coastal water of Iceland that lasted until early 20th century 1600’s Glaciers advance across Europe 1693 Hekla (Iceland) volcano erupts Timeline 1693 Hekla (Iceland) volcano erupts 1694 Unfavorable for crops in Europe 1695 Cold rainy summer, early autumn frost 1696 Still cold and wet conditions 1695-1698 Great famine of Estonia – 75,000 people dies Price of wheat, 1200-1900 Skies/clouds in paintings 5 major phases in the Northern Hemisphere in last 1400 years Modern climatic optimum 1890 - 2001 AD