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 EasterbrookDept of Geology, Western Wash Univ.Bellingham, WA

THE PAST IS THE KEY THE PAST IS THE KEY TO THE FUTURETO THE FUTURE

Charles Lyell (1797) – “The present is the Charles Lyell (1797) – “The present is the key to key to the past.”the past.”

To understand present-day climate To understand present-day climate changes, changes, we need to know how climate we need to know how climate has behaved has behaved in the past.in the past.

In order to predict where we are heading, In order to predict where we are heading, we we need to know where we’ve been. need to know where we’ve been.

Historic temperature Historic temperature measurementsmeasurements

Oxygen isotope ratios Oxygen isotope ratios in deep ice coresin deep ice cores..

Advance and retreat of Advance and retreat of glaciers. glaciers.

Measuring climatic warming/cooling in the geologic past

Data in this presentation may be found in this volume

Periods of Periods of warming and warming and

cooling during cooling during the past the past centurycentury

The ratio of 18O to 16O 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 18O/16O ratio from a standard.

δ18O = (18O/16O)sample ‒ (18O/16O) _________________________________ x 103

(18O/16O)standard

where δ18O is the of ratio 18O/16O 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

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 CO2

Warm/cool periods over the past 5,000 Warm/cool periods over the past 5,000 yearsyears

The Medieval The Medieval Warm Period Warm Period and Little Ice and Little Ice AgeAge

2400 publications 2400 publications including many including many booksbooks (Loehle, 2007)

Mann et al. (1998)

Little Ice Age morainesLittle Ice Age moraines

Periods of warming and cooling in the past 10,00 years

Abrupt, Abrupt, intense intense periods of periods of global global warming 10-warming 10-15,000years 15,000years agoago

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

Some examples of intense global warming and cooling 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.

Significant periods of warming and cooling Significant periods of warming and cooling that occurred that occurred withinwithin climatic events are climatic events are

recorded in ice sheet advances and recorded in ice sheet advances and retreatsretreats

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 CO2 emissions and cannot have been caused by them.

4. CO2 plays a minor, insignificant role in climate change.

Conclusions about global warming from the past few centuries to 25,000 years ago

The cause of global warming and The cause of global warming and coolingcooling

Relationship Relationship of climate of climate change and change and sea surface sea surface temperaturetemperature—the PDO —the PDO and AMOand AMO

PDO and glacier fluctuationsPDO and glacier fluctuations

PDO and sea PDO and sea surface surface

temperaturetemperature

GLACIER FLUCTUATIONS

CLIMATE CHANGES

PDO-AMO MODE CHANGES

WHAT DRIVES PDO-AMO MODES?

PDO COLD MODE (1945-77) PDO WARM MODE (1977-98

Weather patterns for El Nino and La NinaWeather patterns for El Nino and La Nina

Sea surface temperaturesSea surface temperatures

1997

2007

2001

1999

March, March, 20092009

October

2011

Setting up Setting up of the PDO of the PDO cold phase cold phase

assures assures global global

cooling for cooling for the next the next ~25-30 ~25-30 yearsyears..

How cold will it get?How cold will it get?

Cold PDO firmly entrenched since 1999Cold PDO firmly entrenched since 1999

Computer models are the Computer models are the only basis for claiming only basis for claiming CO2 is causing global CO2 is causing global warming. IPCC models warming. IPCC models predicted 1ºF warming predicted 1ºF warming from 2000 to 2011.from 2000 to 2011. However, temperatures However, temperatures have cooled so the have cooled so the models have been models have been proven wrong. proven wrong.

IPCC predictions vs. reality

GLACIER FLUCTUATIONS

CLIMATE CHANGES

PDO-AMO MODE CHANGES

WHAT DRIVES PDO-AMO MODES?

Maunder Sunspot Minimum Maunder Sunspot Minimum

Global cooling occurs during times of Global cooling occurs during times of few sunspots and low solar irradiancefew sunspots and low solar irradiance

Correlation Correlation between between

solar activity solar activity and climateand climate

Change in Change in production production

rate of rate of radiocarbon radiocarbon

and and temperature temperature

Correlation of SOI and solar activityCorrelation of SOI and solar activity

Svensmark, CERN experiments Svensmark, CERN experiments

Variations in the sun’s magnetic field Variations in the sun’s magnetic field affects cosmic radiation received by the affects cosmic radiation received by the Earth. Earth.

Cosmic rays produce ions that act as Cosmic rays produce ions that act as seeds of condensation (clouds).seeds of condensation (clouds).

Increased cloudiness results in climatic Increased cloudiness results in climatic coolingcooling..

Cloud cover and cosmic raysCloud cover and cosmic rays

CONCLUSIONSCONCLUSIONS

Many periods of natural warming and cooling have occurred in the Many periods of natural warming and cooling have occurred in the past past 15,000 years, long before CO15,000 years, long before CO22 could have caused them. could have caused them.

More than 40 periods of global warming/cooling have occurred in the More than 40 periods of global warming/cooling have occurred in the past 500 past 500 years, none of which could have been caused by COyears, none of which could have been caused by CO22..

Many periods of far more intense warming have occurred from natural Many periods of far more intense warming have occurred from natural causes causes in the past 15,000 years, some as great as 20°F in 40 in the past 15,000 years, some as great as 20°F in 40 years.years.

Almost all of the past 10,000 years has been warmer than present. 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 The Medieval Warm Period and Little Ice Age did occur—the ‘hockey stick’ is stick’ is a bad joke.a bad joke.

The climate has been warming gradually since the Little Ice Age began The climate has been warming gradually since the Little Ice Age began about about 500 years ago. 500 years ago.

Recurring patterns of cyclic global climate change form a reliable Recurring patterns of cyclic global climate change form a reliable basis for basis for predicting future climate changes—the past is the key to predicting future climate changes—the past is the key to the future.the future.

Computer models have failed badly in predicting temperatures.Computer models have failed badly in predicting temperatures.

Glacier fluctuations result from climate changes.Glacier fluctuations result from climate changes.

Climate changes result from changes in the PDO and AMO.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 cool to warm in 1977 and climate warmed; the the PDO flipped from warm to cool in 1999 and climate cooled.PDO flipped from warm to cool in 1999 and climate cooled.

Changes in ocean temperatures correlate well with solar changes.Changes in ocean temperatures correlate well with solar changes.

Changes in the solar magnetic field affect incidence of cosmic rays Changes in the solar magnetic field affect incidence of cosmic rays on on Earth. Changes in cosmic ray intensity affects cloudiness, Earth. Changes in cosmic ray intensity affects cloudiness, which affects which affects global temperatures. global temperatures.

The sun is now in a solar minimum and seems to be heading for the The sun is now in a solar minimum and seems to be heading for the Dalton Dalton Minimum (1790-1820), during which global Minimum (1790-1820), during which global temperatures declined temperatures declined sharply.sharply.

The 1977-1998 global warming period is over and we are now in a period of 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 global cooling that will last several decades, similar to continuing natural cycles dating back thousands of years. cycles dating back thousands of years.

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

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