Geologic evidence Geologic evidence of recurring of recurring

climate cycles and climate cycles and theirtheir implications implications for the cause of for the cause of global warming global warming

and climate and climate changes in the changes in the coming centurycoming century

Don J. Don J. EasterbrookEasterbrook

Geologic issues about Geologic issues about

global climatic warmingglobal climatic warming Is global warming real?Is global warming real?What is the evidence for COWhat is the evidence for CO22 as the cause as the cause

of global warming?of global warming?What is the geologic evidence for natural What is the geologic evidence for natural

cycles as the cause of global warming?cycles as the cause of global warming?

Some Geologic FactsSome Geologic Facts Global climate warmed ~0.6Global climate warmed ~0.6° °

CC from 1910 to ~1940. from 1910 to ~1940.

Global climate cooled ~0.5Global climate cooled ~0.5° C° C from ~1940 to 1977from ~1940 to 1977

Global climate warmed ~0.5Global climate warmed ~0.5° ° CC from 1977 to 2000. from 1977 to 2000.

Global climate cooled ~0.3Global climate cooled ~0.3° C° C between ~1880 to ~1910 between ~1880 to ~1910 and was ~0.9and was ~0.9° C ° C cooler in cooler in 1890 than 2000 1890 than 2000

The global climate has been The global climate has been warming since the Little warming since the Little Ice Age (~400 years).Ice Age (~400 years).

Evidence that COEvidence that CO22 is the cause of global warming is the cause of global warming

CO2 and global temperature have both risen CO2 and global temperature have both risen over the past 30 years.over the past 30 years.

Computer models can be adjusted to show Computer models can be adjusted to show temperatures parallel to global temperaturestemperatures parallel to global temperatures..

Composition of the atmosphere

CO2 now makes up 0.038% of air

Before human input, CO2 was 0.028% to 0.030%

Human input has raised CO2 by 0.008%

Facts:

1. Half of the warming in the past century occurred before CO2 began to rise sharply.

2. For 30 years after CO2 began to soar, global cooling occurred, rather than warming.

3. Of the many global warmings and coolings, only the last one (the past 30 years) corresponds to rising CO2.

.

~80% of CO2 emissions have occurred since 1945

GreenlandGreenland warmingwarming has followed the global has followed the global patternpattern

““Our civilization has never experienced any environmental Our civilization has never experienced any environmental shift remotely similar to this. shift remotely similar to this. Today’s climate pattern has Today’s climate pattern has existed throughout the entire history of human existed throughout the entire history of human civilizationcivilization.”.” (Gore, 2006) (Gore, 2006)

“Temperature has spiked within the past few years unlike any previous temperature spike in history.” (Mote, 2007)

“Current warming is 10 times greater than ever before seen in the geologic record. The chance that warming is natural is less than 10 percent..” (.” (Newsweek, August 13, 2007)

Past climate changes

10 episodes of global warming/cooling in the past 10 episodes of global warming/cooling in the past 15,000 yrs15,000 yrs

What the data showsWhat the data shows Global temperatures have risen 1° F in the last Global temperatures have risen 1° F in the last

century.century. Temperatures in Greenland changed abruptly Temperatures in Greenland changed abruptly

at at least 9 times in the late Pleistocene.least 9 times in the late Pleistocene. Temperature changes of 18-23° F/100 yrs Temperature changes of 18-23° F/100 yrs

occurred 3 times.occurred 3 times. Temperature changes of 13-14° F/100 yrs Temperature changes of 13-14° F/100 yrs

occurred 3 times.occurred 3 times. Temperature changes of 5-7° F/100 yrs Temperature changes of 5-7° F/100 yrs

occurred occurred 4 times.4 times. None of these temperature changes could have None of these temperature changes could have

been caused by manmade CObeen caused by manmade CO22 emissions. emissions.

Holocene climate changesHolocene climate changes

Rapid cooling and warming at 8200 yrs. Rapid cooling and warming at 8200 yrs. B.P.B.P.

Medieval Warm PeriodMedieval Warm Period

The Medieval Warm Period was a time of warm climate ~900–1300 AD. Grain crops flourished in Europe.

The population more than doubled and many new cities arose. The Vikings took advantage of the warm climatic to colonize Greenland. Wine grapes were grown as far north as Britain. Prolonged droughts affected the southwestern U.S. Western North America warmed, glaciers receded. An eastern Antarctic Peninsula ice core shows warmer temperatures

Sediments in Lake Nakatsuna in Japan record warmer temperatures. Sea surface temperatures in the Sargasso Sea were approximately 1°C

warmer than today. Equatorial east Africa was drier from 1000-1270 AD. The Medieval Warm Period appears to have been a global event.

LITTLE ICE AGELITTLE ICE AGE ~1300 AD, temp. dropped ~4° C (7° F ) in ~20 yrs~1300 AD, temp. dropped ~4° C (7° F ) in ~20 yrs

Much colder and wetter, ~4° C cooler than presentMuch colder and wetter, ~4° C cooler than present

Violent storms, early snow, floodingViolent storms, early snow, flooding

Glaciers advanced all over the world. Glaciers advanced all over the world.

Massive crop failures in Europe--large population Massive crop failures in Europe--large population decline in Europe; ~1.5 million people died; decline in Europe; ~1.5 million people died;

Wine production dropped sharply Wine production dropped sharply

Themes River in London froze overThemes River in London froze over

Solar irradiance, sunspots, and glaciersSolar irradiance, sunspots, and glaciers

Boulder Glacier, Mt. BakerBoulder Glacier, Mt. Baker1940 to 1956 1956 to 1979

Easton Glacier, Mt. BakerEaston Glacier, Mt. Baker1940 to 1956 1956 to 1979

Comparison of glacial activity and ocean temperaturesComparison of glacial activity and ocean temperatures

Facts About Global Climate Change Facts About Global Climate Change Over the Past Century and MillenniaOver the Past Century and Millennia

Evidence for recurring cycles of global climate change over the Evidence for recurring cycles of global climate change over the past centuries and millennia clearly show many natural climatic past centuries and millennia clearly show many natural climatic warming and cooling events, long before COwarming and cooling events, long before CO22 emissions raised emissions raised atmospheric COatmospheric CO22 levels. levels.

Greenland ice core isotope and temperature data show 10 Greenland ice core isotope and temperature data show 10 periods of climatic warming far greater than recent warming (up periods of climatic warming far greater than recent warming (up to 20 times greater per century). Glacier fluctuations and ice to 20 times greater per century). Glacier fluctuations and ice core data show a repeating pattern of warm/cool episodes in the core data show a repeating pattern of warm/cool episodes in the past 500 years and we are right on schedule with two cooling past 500 years and we are right on schedule with two cooling periods and two warming periods this century. All of the global periods and two warming periods this century. All of the global warming in the past 500 years can be explained by these warming in the past 500 years can be explained by these natural climatic cycles.natural climatic cycles.

Past climate changes follow cyclic 25-35 year patterns that can Past climate changes follow cyclic 25-35 year patterns that can be traced for the past 400–1000 years in Greenland ice cores, be traced for the past 400–1000 years in Greenland ice cores, glacier fluctuations, and historic observations. glacier fluctuations, and historic observations.

The Earth is now near the end of a 30–year warm cycle, fitting The Earth is now near the end of a 30–year warm cycle, fitting the pattern of comparable cycles over the past 200 years. the pattern of comparable cycles over the past 200 years.

The current warm cycle coincidently corresponds to high The current warm cycle coincidently corresponds to high atmospheric COatmospheric CO22 levels. However, the preceding 30–year levels. However, the preceding 30–year global cooling cycle (1945-1977) occurred despite the global cooling cycle (1945-1977) occurred despite the dramatic rise in COdramatic rise in CO22 emissions that began about 1945). emissions that began about 1945).

About half of the global warming of the past century About half of the global warming of the past century occurred before 1945, so increased atmospheric COoccurred before 1945, so increased atmospheric CO22 clearly did not control global climate changes then. The clearly did not control global climate changes then. The abrupt shift in 1977 from the 1945-1977 cool period to abrupt shift in 1977 from the 1945-1977 cool period to the 1977-2007 warm period was not reflected by any the 1977-2007 warm period was not reflected by any significant change in COsignificant change in CO22..

The only physical evidence for COThe only physical evidence for CO22 causing global causing global warming is that warming and COwarming is that warming and CO22 have both risen for the have both risen for the past 30 years. past 30 years. AfterAfter CO CO22 began to soar in 1945, global began to soar in 1945, global coolingcooling occurred for 30 years, rather than warming. occurred for 30 years, rather than warming.

CO2 began to rise sharply in 1945, but global temperatures declined for 30 years

Solar eff ects and climate changeSolar eff ects and climate change

Global climate changes correlate well with changes in:

1. Solar irradiance.

2. Numbers of sunspots.

3. Production of 10Be and 14C in the atmosphere from radiation.

Few sunspots during the Little Ice AgeFew sunspots during the Little Ice Age

Global temperature change and Global temperature change and sunspotssunspots

Solar irradiance and global Solar irradiance and global warmingwarming

25-30 yr. global warming/cooling phases that 25-30 yr. global warming/cooling phases that occurred during the past century coincided with occurred during the past century coincided with changes in solar irradiancechanges in solar irradiance..

Global climate changes in the geologic past have Global climate changes in the geologic past have coincided with changes in production rates of coincided with changes in production rates of 1414C C and and 1010Be.Be.

Where are we headed during the coming century?

ICPP predictions

Global temperatures will increase as much as 10° F by 2100

Predicted global temperature changes this centuryPredicted global temperature changes this century

Predicted global temperature changes this centuryPredicted global temperature changes this century

The IPCC predicts that global temperature will rise 1° The IPCC predicts that global temperature will rise 1° F (above present temp) by 2011, whereas the pattern F (above present temp) by 2011, whereas the pattern of natural warm/cool cycles predicts slight cooling. of natural warm/cool cycles predicts slight cooling. The difference is so large, that in only 3 years we The difference is so large, that in only 3 years we should know which direction we’re heading.should know which direction we’re heading.

The predicted IPCC temperature increase by 2011 is The predicted IPCC temperature increase by 2011 is 1° F greater than that predicted by extrapolation of 1° F greater than that predicted by extrapolation of past climatic cycles and nearly 2° F greater by 2030. past climatic cycles and nearly 2° F greater by 2030. These differences are greater than warming of the These differences are greater than warming of the entire past century, so should be easily detectible. entire past century, so should be easily detectible. Thus, the next few years may tell us whether we're Thus, the next few years may tell us whether we're heading for the global catastrophe predicted by IPCC heading for the global catastrophe predicted by IPCC or minor warming predicted by climate cycles. or minor warming predicted by climate cycles.

Two choices:Two choices:

If past climate cycles persist and climate If past climate cycles persist and climate cools in the next 30 years (rather than cools in the next 30 years (rather than soaring), the IPCC will have been the soaring), the IPCC will have been the greatest scientific boondoggle in the history greatest scientific boondoggle in the history of science.of science.

If IPCC predictions are correct, we’re headed If IPCC predictions are correct, we’re headed for the greatest global catastrophe since the for the greatest global catastrophe since the Little Ice Age.Little Ice Age.

What lies ahead in this What lies ahead in this century?century?