Friday, 15 May 2015

200 years of data shows climate changes accelerating

The Radcliffe Meteorological Station in Oxford has just celebrated 200 years of daily weather observations, possibly the longest run of daily records for any single location in the world. Now located in the garden of Green College beside the old observatory building, adjacent to the new Mathematical Institute, it has temperature and rainfall records continuous from January 1815, as well as irregular observations of rainfall, cloud and temperature from 1767 to 1814.
"Green Templeton College in Snow 2009". Note the weather station's Stevenson screen visble on the right of the photo.
Licensed under CC BY 3.0 via Wikipedia.

These records show some worrying statistics, indicating that Britain's weather is becoming more extreme as it becomes warmer (a phenomenon due to in part to warmer air being able to carry more energy and moisture). 2014 was Oxford’s warmest year since records began in 1815, and part of a very warm trend since 1990. The average annual temperature for 2014 was 11.5°C (53°F), 1.8 degrees Celsius (over 3 degrees Fahrenheit) above the 200-year average of 9.7°C (49½°F), a significant difference in weather terms. This was accompanied by extremes of wet or dryness. September 2014 was the second driest on record and yet the winter rainfall total for December 2013 to February 2014 was the wettest winter quarter again since 1815. As a single month January 2014 was the wettest of all winter months with rainfall of 146.9mm (almost 6 inches) was nearly three times the month’s long-term average in Oxford of 52.9mm.

Although these figures may sound quite unexceptional,they are a clear indication that weather is changing, and much more rapidly over the past couple of decades than for most of the previous 180 years.

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