Accuweather.com - 4/23/13
The Earth's climate warmed more during the 30-year period between 1971-2000 than any other three-decade period in the last 1,400 years, according to a new international study
The regional study, which was published in the journal Nature Geoscience by 80 international scientists, looked at historical records and data taken from tree rings, pollen, cave formations, ice cores and ocean/lake sediments from the seven continents.
The study also showed that the MedievalWarm Period that took place between 950 and 1250 AD may not have been global as other research has also indicated.
Excerpt below from the The Earth Institute Columbia University.....
Some people have argued that the natural warming that occurred during the medieval ages is happening today, and that humans are not responsible for modern day global warming. Scientists are nearly unanimous in their disagreement "If we went into another Medieval Warm Period again that extra warmth would be added on top of warming from greenhouse gases," said study co-author Edward Cook, a tree-ring scientist at Lamont-Doherty Earth Observatory.
The most consistent trend across all regions in the last 2,000 years was a long-term cooling, likely caused by a rise in volcanic activity, decrease in solar irradiance, changes in land-surface vegetation, and slow variations in Earth's orbit. With the exception of Antarctica, cooling tapered off at the end of the 19th century, with the onset of industrialization.
Link: Accuweather.com
