Most of the warming will be experienced in the winter, rather than summer, months. The frequency, intensity, and duration of cold air outbreaks is expected to decrease during this century. In the summer, the number of extreme heat days – those over 90° F – are expected to increase, although the increase is likely to be less along the Cape than in other locations in the Northeast. Furthermore, the character of heat waves is expected to change in the Northeast, becoming more frequent, intense, and prolonged.
Figure 1 (from the Union of Concerned Scientists report, “The Changing Northeast Climate – Our Choices, Our Legacy”) shows how changes in average summer heat index will strongly alter how summer feels to residents of the Massachusetts. Red arrows track what summers in Massachusetts could feel like over the course of the century if we follow a higher-emissions pathway. Yellow arrows track what states could feel like on a lower-emissions pathway, demonstrating that our emissions choices make a difference.
Predictions reported in the 2011 assessment by the Commonwealth of MA are shown in Table 2.
Increases in air temperatures may impact the intensity of wind by changing temperature gradients. Higher winds can lead to more severe coastal erosion and sediment transport, which may impact shellfish resources.
Sea surface temperatures are also predicted to rise, by up to 4 to 8° F by end of the century. The MA EOEA (2011) assessment reported an average annual sea surface temperature of 53° F in coastal MA waters, which may increase to 55-56° F by 2050 and 57-61° F by 2100.
Coupled with warmer winters, winter ice cover is predicted to decline, although there will be variation from winter to winter.
(average of observed data over 1961–1990)
(based on average of 2035–2064 predictions)
(based on average of end-of-century predictions)
|Annual Temperature||46° F||50-51° F||51-56° F|
|Summer Temperature||68° F||72-73° F||72-78° F|
|Winter Temperature||23° F||25-28° F||27-33° F|
Table 2. Predictions reported in the 2011 assessment by the Commonwealth of MA (MA EOEA 2011).
Water and Air Temperature Impacts Relevant to Shellfishing
Warming air and water temperatures may impact coastal embayments like Wellfleet Harbor in various ways:
Implications for Shellfishing
Warming air and water temperatures in Wellfleet Harbor may :