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.
Climate change indicators continue to show the impacts from a warming world.
Despite the rapid warming trend and resulting loss of permafrost, methane levels along Alaska's Arctic slope have been fairly stable over the past 29 years.
This year could challenge 2012 for the lowest sea ice extent minimum in the satellite record for the Arctic region.
Large portions of northern North America have experienced a greening trend over the past three decades.
New research explains why the Southern ocean surrounding Antarctica has not warmed like the rest of the world's oceans.
The warming influence of carbon dioxide has increased by 50 percent above pre-industrial levels during the past 25 years, according to NOAA.