Posted: 10/29/2003
Climate Records Contradict Global Warming Claims
UN Climate Report Authors Manipulate Data to Support Assertions, Says NCPA Scholar
DALLAS, TX (October 29, 2003) – Overwhelming scientific evidence suggests the Earth’s current warming trend is part of a natural pattern of temperature fluctuations rather than a phenomenon caused by human activity, according to a report by the National Center for Policy Analysis (NCPA).
According to the NCPA analysis, the vast amount of scientific evidence establishes that the Earth’s climate went through a period of warming during medieval times, followed by a Little Ice Age that persisted into the 19th century. Yet promoters of the theory that humans are causing global warming reject this fact, and instead claim that temperatures were relatively stable over the last 1,000 years—until greenhouse gases from burning fossil fuels caused significant warming during the past several decades. This view was promoted by the Third Assessment Report (2001) of the United Nations Intergovernmental Panel on Climate Change (IPCC).
“Global Warming theorists with the IPCC have grossly manipulated the data to arrive at their pre-determined conclusions,” said David R. Legates, NCPA Adjunct Scholar and associate professor and director of the Center for Climatic Research at the University of Delaware. For example:
- The historical climate reconstruction in the IPCC report primarily used tree ring records to infer air temperature trends for past centuries.
- Then, the surface temperature record of the 20th century was attached to the end of the proxy record—although instrumental air temperature readings are not directly comparable to proxy records.
- Putting the two different sets of data together created a “hockey stick” appearing to show a dramatic rise in temperatures during the 1990s (see figure).
“IPCC authors compare apples to oranges in order to arrive at their pre-determined destination,” said Legates. “Policy makers should know about this faulty science before they support policies to reduce global warming that are unnecessary, costly and ineffective.”
The NCPA analysis is available online: Revising 1,000 Years of Climate History