In a new study published in the journal Climate of the Past, a team of geophysicists at UMass Amherst have reconstructed the highest resolution temperature record for New England, stretching back 900 years to the Middle Ages. The temperature data set gives new insight into the climate in Northeastern U.S. – but what is conspicuously absent is any trace of manmade global warming.
A New Technique
The study was conducted using a relatively new technique involving measuring the quantity of certain chemical compounds, called branched glycerol dialkyl glycerol tetraethers (GDGTs), found in lakes and soil. They correlate well with temperature variation and can therefore be used as a form of thermometer.
What is particularly advantageous about this method is that it allows for a more fine-grained resolution in time. The work, led by doctoral student Daniel Miller, resulted in a temperature measurement every seven years on average during the 900-year interval. This high resolution allowed them to discover a 50-to-60-year temperature cycle hitherto undetected in other studies.
Although this study is only regional, covering a relatively small part of the U.S., one can still find the fingerprints of global climate events. Most notably, the Medieval Warm Period can be clearly seen. A millennium ago, the North Atlantic region was so warm that wine grapes grew in Scotland and Norwegian explorers were able to settle and farm in Greenland. In central Europe, the warm period caused a major economic boom and repopulation and it was during this time that the great cathedrals were built.
But it was not to last. It was succeeded by the Little Ice Age, a cold spell clearly seen in the graph lasting a whopping 500 years until the end of the 19th century. During this period, it was so cold in Europe that the river Thames in London froze during winter, and crops failed during summer.
Where’s Manmade Warming?
However, the most peculiar finding is the lack of warming in the last 100 years. We can see a spike in temperature, but the data indicates a peak in the middle of the 20th century, followed by cooling for the last 50 years. According to the study, present day is the coldest period seen in New England in 900 years.
Many caveats need to be inserted here: It is only a single study, it is only regional, the proxy chemical used could be flawed, it could be calibrated improperly, and there may be errors in parts of the data record. Nevertheless, taken at face value, the paper shows not a single trace of manmade global warming.