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The past is the key to the future: Ice core isotope data, glacial fluctuations, decadal sea surface temperature changes, solar variations, and historic measurements. Don J Easterbrook Dept of Geology, Western Wash Univ. Bellingham, WA
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THE PAST IS THE KEY TO THE FUTURE Charles Lyell (1797) – “The present is the key to the past.” To understand present-day climate changes, we need to know how climate has behaved in the past. In order to predict where we are heading, we need to know where we’ve been.
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Historic temperature measurements Oxygen isotope ratios in deep ice cores. Advance and retreat of glaciers. Measuring climatic warming/cooling in the geologic past Data in this presentation may be found in this volume
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Periods of warming and cooling during the past century
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The ratio of 18 O to 16 O depends on the temperature at the time snow crystals formed in the atmosphere. The oxygen isotopic composition of a sample is expressed as a departure of the 18 O/ 16 O ratio from a standard. δ 18 O = ( 18 O/ 16 O) sample ‒ ( 18 O/ 16 O) _________________________________ x 10 3 ( 18 O/ 16 O) standard where δ 18 O is the of ratio 18 O/ 16 O expressed as per mil (0/00) The GISP2 isotope data reflects Greenland temperatures but excellent correlation with global glacier fluctuations makes it a good proxy for global temperatures. GREENLAND GISP2 ICE CORE
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Periods of warming and cooling in the past 500 years Isotope data from Greenland ice cores shows 40 periods of warming/cooling, none of which could be caused by CO 2
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Warm/cool periods over the past 5,000 years
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The Medieval Warm Period and Little Ice Age 2400 publications including many books (Loehle, 2007) Mann et al. (1998)
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Little Ice Age moraines
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Periods of warming and cooling in the past 10,00 years
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Abrupt, intense periods of global warming 10-15,000years ago
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1.Global warming has occurred many times in the last 25,000 years, all caused by natural, recurring processes. 2.The magnitude and intensity of global warming during the past century is insignificant compared to the magnitude and intensity of the profound natural climate reversals over the past 25,000 years, Global warming/cooling in past 25,000 years
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Some examples of intense global warming and cooling 1. About 24,000 years ago, while huge continental glaciers covered large areas, a sudden warming of about 20°F occurred. Soon thereafter, temperatures dropped abruptly about 11°F and temperatures remained cold for several thousand years but oscillated between about 5°F warmer and cooler. 2. About 15,000 years ago, a sudden, intense, climatic warming (about 21°F, ~12° C;) caused dramatic melting of the large ice sheets that covered most of the world. 3. A few centuries later, temps plummeted~ 20° F (~11°C) and ice sheets readvanced. 4. About 14,000 years ago, temperatures rose rapidly, about 8° F (~4.5°C), and the ice sheets receded. 4. About 13,400 years ago, temperatures plunged, ~14° F (~8°C) and ice sheets readvanced. 5. About 13,200 years ago, temps rose rapidly, 9° F (~5°C), and ice sheets receded. 6. 12,700 yrs ago temperatures plunged sharply, 14° F (~8°C) and a 1300-year cold period, the Younger Dryas, began. 7. After 1300 years of cold climate, temperatures rose sharply, ~21° F (~12° C), 11,500 years ago, marking the end of the Younger Dryas cold period and the end of the Pleistocene Ice Age.
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Significant periods of warming and cooling that occurred within climatic events are recorded in ice sheet advances and retreats
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1.Global warming has occurred many times in the last 25,000 years, all caused by natural, recurring processes. 2.The magnitude and intensity of global warming during the past century is insignificant compared to the magnitude and intensity of the profound natural climate reversals over the past 25,000 years, 3.All of these periods of global warming occurred long before any significant rise in human CO 2 emissions and cannot have been caused by them. 4.CO 2 plays a minor, insignificant role in climate change. Conclusions about global warming from the past few centuries to 25,000 years ago
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The cause of global warming and cooling Relationship of climate change and sea surface temperature —the PDO and AMO
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PDO and glacier fluctuations
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PDO and sea surface temperature
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GLACIER FLUCTUATIONS CLIMATE CHANGES PDO-AMO MODE CHANGES WHAT DRIVES PDO-AMO MODES?
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Weather patterns for El Nino and La Nina
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Sea surface temperatures 1997 2007 2001 1999
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March, 2009 October 2011
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Setting up of the PDO cold phase assures global cooling for the next ~25-30 years.
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How cold will it get?
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Cold PDO firmly entrenched since 1999
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Computer models are the only basis for claiming CO2 is causing global warming. IPCC models predicted 1ºF warming from 2000 to 2011. However, temperatures have cooled so the models have been proven wrong. IPCC predictions vs. reality
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GLACIER FLUCTUATIONS CLIMATE CHANGES PDO-AMO MODE CHANGES WHAT DRIVES PDO-AMO MODES?
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Maunder Sunspot Minimum
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Global cooling occurs during times of few sunspots and low solar irradiance
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Correlation between solar activity and climate Change in production rate of radiocarbon and temperature
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Correlation of SOI and solar activity
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Svensmark, CERN experiments Variations in the sun’s magnetic field affects cosmic radiation received by the Earth. Cosmic rays produce ions that act as seeds of condensation (clouds). Increased cloudiness results in climatic cooling.
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Cloud cover and cosmic rays
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CONCLUSIONS Many periods of natural warming and cooling have occurred in the past 15,000 years, long before CO 2 could have caused them. More than 40 periods of global warming/cooling have occurred in the past 500 years, none of which could have been caused by CO 2. Many periods of far more intense warming have occurred from natural causes in the past 15,000 years, some as great as 20°F in 40 years. Almost all of the past 10,000 years has been warmer than present. The Medieval Warm Period and Little Ice Age did occur—the ‘hockey stick’ is a bad joke. The climate has been warming gradually since the Little Ice Age began about 500 years ago. Recurring patterns of cyclic global climate change form a reliable basis for predicting future climate changes—the past is the key to the future. Computer models have failed badly in predicting temperatures.
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Glacier fluctuations result from climate changes. Climate changes result from changes in the PDO and AMO. The PDO flipped from cool to warm in 1977 and climate warmed; the PDO flipped from warm to cool in 1999 and climate cooled. Changes in ocean temperatures correlate well with solar changes. Changes in the solar magnetic field affect incidence of cosmic rays on Earth. Changes in cosmic ray intensity affects cloudiness, which affects global temperatures. The sun is now in a solar minimum and seems to be heading for the Dalton Minimum (1790-1820), during which global temperatures declined sharply. The 1977-1998 global warming period is over and we are now in a period of global cooling that will last several decades, similar to continuing natural cycles dating back thousands of years.
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Dogma is an impediment to the free exercise of thought. It paralyses the intelligence. Conclusions based upon preconceived ideas are valueless. It is only the open mind that really thinks. Patricia Wentworth, 1949 For data and information go to: Bing.com or Google.com and enter Don Easterbrook global warming
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