World temperatures highest in 1200 years
Rhett A. Butler, mongabay.com
February 10, 2006
World temperatures are higher than in any period over the last 1,200 years, according to a study published in the current issue of Science.
In reaching their conclusion, a research team from the University of East Anglia in Britain analyzed 14 sets of temperature records including data from rings, fossil shells, ice cores, temperature records, and historical documents from North America, Europe and East Asia.
“Our results show that, during the late 20th century, warming affected the entire northern hemisphere and that at no point in the past 1,000 years has the northern hemisphere experienced the same widespread warming,” said Dr. Timothy Osborn, co-author of the study.
Their research showed significant warmth in the Northern Hemisphere from 890-1170 A.D. follwed by colder periods from 1580-1850, the period known as the “little ice age”. The scientists said the present warm phase is longest temperature anomaly since the 9th century.
Images courtesy of the NASA Goddard Institute for Space Studies
According to NASA, the highest global surface temperature in more than a century of instrumental data was recorded in the 2005 calendar year in the GISS annual analysis. However, the error bar on the data implies that 2005 is practically in a dead heat with 1998, the warmest previous year.
“The key conclusion was that the 20th century stands out as having unusually widespread warmth, compared to all of the natural warming and cooling episodes during the past 1,200 years,” Dr. Osborn said.
Their study follws research published last November which found that atmospheric dioxide levels are presently at the highest in 650,000 years. Another study, released earlier this year by NASA, found that 2005 was the warmest year on record.