The George C. Marshall Institute
HOME ABOUT US CONTACT US
CLIMATE CHANGE

ENERGY POLICY

MISSILE DEFENSE

SPACE SECURITY &
NATIONAL DEFENSE

SCIENCE & PUBLIC POLICY

CYBERSECURITY

ANNUAL AWARDS DINNER

JOIN OUR E-MAIL LIST
SITE SEARCH

Climate Change Science


There remains considerable uncertainty as to how much the climate has varied regionally and globally on the decades-to-centuries timescale, or what caused those changes.  Yet we need to know how natural climate fluctuations are caused in order to determine to what extent human activities have affected the climate system.

 

Furthermore, the temperature pattern of the last century is not consistent with the assertion that man-made emissions of greenhouse gases are the only contribution to periods of global warming.  In the early part of the 20th century, temperature increased.  Then from about 1940 until the 1970s, there was a slight cooling.  Temperatures again increased since the 1970s, but since about 2001 increases in the global surface temperature have stopped ? even though greenhouse gas (GHG) emissions continued to increase and have increased steadily in the latter half of the 20th century.

 

Naturally occurring greenhouse gases warm the Earth by about 30oC (54 oF).  Because of the complexities of the climate system, there is no accepted estimate of the amount of warming due to the human emissions of greenhouse gases.

 

 

Shattered Consensus: The True State of Global Warming
By Patrick J. Michaels
Shattered Consensus convincingly demonstrates the remarkable differences between what we commonly read about global warming and what is really happening. Nine chapters describe major problems with computer simulations of future climate that are the basis for wrenching policies being proposed by world leaders. Anyone who reads this book will come away with a new appreciation of the complexity of the climate issue and will question the need for expensive policies that are likely to have little or no detectable effect on the planet's temperature. Published in cooperation with the George C. Marshall Institute.


Over 99.9 percent of the dry atmosphere is nitrogen, oxygen and argon, which are not greenhouse gases. The amount of water vapor, the most important greenhouse gas in the atmosphere, depends on temperature and relative humidity, ranging from near zero in cold, dry polar air, to more than 6 percent in humid tropical air.  Other greenhouse gases, carbon dioxide, etc., amount for less than a tenth of a percent of the atmosphere.  CO2 accounts for the majority of human emissions of greenhouse gases.

 

Atmospheric concentration of CO2 has varied greatly over time, from a high of as much as 4,000 parts per million (ppm) 200 million years ago to a low of about 180 ppm during several periods of glaciation over the past 400,000 years.  It was relatively constant at about 280 ppm for 1,000 years before 1750.  Since 1750, CO2 concentration has risen, reaching 386 ppm in 2009. [For more on carbon dioxide concentrations see Trends in Atmospheric Carbon Dioxide - Mauna Loa]

 

Much of what we are told about the future climate is the result of computer model predictions which, while they have lots of equations, are significantly incomplete approximations of the behavior of the real world climate.  They also make assumptions about economic activity which are the basis for the inputs of CO2 and other well-mixed greenhouse gases.  These models are mathematical representations of climate processes, but many of these processes, such as clouds and precipitation, are not well enough understood to make multi-decadal predictions of how they would change in the future.  IPCC models are just hypotheses, not established scientific fact.  In fact, with respect to climate predictions decades into the future, they cannot even be tested in order to quantify their skill!

 

We also do not adequately understand natural variability in climate and its relationship to water vapor and cloud formation, aerosols, solar impacts, vegetation interactions, and oceans.  The climate models are based on their prediction that the direct warming from increases in CO2 will be amplified by changes in clouds and other processes.  The claim that models can mimic the global average surface temperature trends observed over the last century only when human effects are included neglects to report that none of the predictions have shown any skill in regional climate change over the last century.  Moreover, even the global average surface temperature trend has warming and cooling during the 20th century, which is replicated in the climate models only by adjusting the amount of aerosols that they insert into the models over this time period.  In the last 10 years or so, the climate models have not even shown skill in predicting the global average surface temperature trend.  The IPCC models, while useful to help us better understand climate processes, fail to provide predictions useful in making public policy.

 

For 20 years, the Institute?s Climate Change program has examined these and other questions to help the public and policy makers better understand the natural climate and claims about global warming.  Despite the billions of dollars spent on climate science and advocacy each year, science does not work by consensus.  Science and knowledge advance by challenging prevailing views and theories through the collection, analysis and testing of data, observations, and hypotheses.

Climate Change Science


Printer Friendly Version | Send to a Friend

1601 North Kent St., Suite 802
Arlington, VA 22209
phone: 571.970.3180
fax: 571.970-3192
info@marshall.org