Climate Change in Connecticut

For the past quarter century, global warming have been the subject of many scientific studies that relate to its causes and the resultant effects.  An often cited study in Connecticut showed the large reduction in shade tobacco  production was highly correlated with the increase in the global temperature.   However the tobacco have no idea what the global temperature is when compared to the local climate. Often studies use the global warming models to provide the local data at a proposed future date to determine local effects.  However, the climate models lack verification and the study on possible effects are what “could happen.”

It was decided to look at the climate in Connecticut over the past half century.  Data was obtained for Bradley International Airport that represents interior areas and Bridgeport Sikorsky  Airport  on the coast. The period chosen was a period in which missing data was not a factor in the analysis.  Bradley Airport was developed after World War II and had several periods of missing data in the 1950s.  Therefore the period of analysis selected was December 1960 to February 2016.  The seasons chosen will follow the meteorological seasons where winter is December thru February.  Both sites are first order NOAA weather stations and are well maintained.  Temperatures were examined on a seasonal basis for both the maximum and minimum daily  observations.

The mean annual temperature increased 2.1°F during the period.  A running average showed relative warm temperatures in the 1970s with gradual increases after 1990.  Years with maximum temperatures were 1973, 1991, 1998, 2006, 2010 and 2012.  However, variations of 3 to 4°F occurred within two years numerous times throughout the period.   The temperatures were then examined on a seasonal basis for the maximum and minimum temperatures

The winter of 1960-61 was the coldest winter during the period with the minimum temperature 5 days  below -18°F and only 7 days that remained above 32°F.  There were 18 days below zero and 28 days between 0 and 10 days.   The minimum temperature show a 5°F increase over the period with  relatively high temperature in the mid 1970s and about 2000, after which they tended to decline.  The warmest winters were 1997-8, 2001-2, 2011-2 and 2015-6.  Year to year variations were often 6-8°F.

It should be noted that the minimum temperatures are primarily affected  by the amount of water vapor in the air.  The winter maximum temperatures increase 4.5°F during the period with the warmest in 2001-2.  Average temperatures became cooler in later years.

The highest summer night minimum temperature occurred in the 1970s with a value of 63.5°F.  The temperatures then cooled until the 1990s with warmer temperatures at the current time with a total increase of 2,1°F.  The daytime maximum temperature was highest in the 1970s and gradually cooled in late years with a net cooling of 0.2°F during the period.  This period of net cooling in the summer maximum temperatures extends over most of interior New England.  Year to year changes in the temperature varies about 4°F with 85°F for the summer maximums.  The average number of days above 90°F decreased about 1.6 days during the period with a similar increase in the number of 80 degree days.

Bridgeport is located directly on the shore of Long Island Sound and is heavily influenced by  its temperatures.   Available temperatures for the Sound show that the temperature increased by 2.1°F from 1976 to 2011.  The increase is similar to other observations along the Southern New England coast.  The temperatures at Bridgeport increased at about the same rate as the water temperatures.

The net effect of climate changes can be summarized as follows.

  • Temperatures at night are warming faster than the day. A previous study showed there are fewer days of very low temperature in recent years.
  • Winter temperatures have cooled since 2000
  • Maximum summer time temperatures show no increase during the period 1961-2015 with a small decrease in 90 degree days

The effect on the inhabitants would be slightly reduced winter heating bills.  I would expect minimal long term effects on the plants or animals in the region with a larger effect resulting from the larger year to year changes in temperature.