Was this winter our ‘new normal’?

 


 

By: Eric Walberg, Senior Program Leader, Climate Services Program

 

As communities across New England continue to clean up downed trees and repair coastal damage, many people are asking if the series of powerful coastal storms that we experienced this winter are the new normal. While it is difficult to know exactly what next winter will bring, we can certainly identify a set of climate change-related factors that contributed to the difficulties that we experienced over the last few months. 
 

Climate change has progressed to the point where all of our weather is impacted. The context has changed so that all of our weather now occurs against the backdrop of a warmer atmosphere, a warmer ocean with higher sea levels, and an enhanced hydrologic cycle (the process of water evaporating, forming clouds, and returning as precipitation). Short term weather variability is still a significant factor in coastal storms, although even the nature of that variability is being altered by climate change. It is possible to differentiate a set of factors that have a direct link to impactful coastal storms from those factors where the linkage is less well understood.

 

The following elements all play a direct role in the characteristics of damaging coastal storms like those that we experienced this winter and the associated trends can help us understand where we are headed:

 

  • Sea level continues to rise, providing a higher launch point for storms and enhancing coastal flooding;
  • Ocean temperatures continue to rise, providing increased energy for coastal storms;  
  • Atmospheric temperatures continue to rise, supporting an exponential increase in the water holding capacity of the atmosphere.
     

An additional factor impacting the mid-Atlantic and New England is the climate-related slowing of the Atlantic meridional overturning circulation (AMOC). The slowing of the AMOC—often called the conveyor belt of the ocean—is both enhancing sea level rise along this reach of the coast and increasing ocean temperatures at rates that exceed most other regions. 

 

In combination, these factors point to a future with increasingly impactful coastal storms for New England due to enhanced storm surge and freshwater flooding, increasingly heavy precipitation, and more powerful winds.

 

The future frequency and track of coastal storms are important factors that are less well understood. Some research points towards a slowing in the progression of steering currents in the atmosphere that influence how rapidly weather systems progress from west to east. This change could lead to periods where a single storm stalls or a series of storms follow similar tracks. (Conversely, this slowing of the steering currents could also lead to periods with little storm activity.) 

 

Given the increasing challenges for the coastal zone in New England, what is the appropriate response? Many studies show that measures taken to adapt to changing coastal flood threat reduce long-term costs. Green infrastructure solutions have the potential to provide multiple benefits including reduced vulnerability to flooding, support of biodiversity, and improved health and quality of life for citizens. In Massachusetts, the Municipal Vulnerability Preparedness (MVP) program is providing grant funding to localities to begin the process of assessing risk and planning for climate resiliency. Applications are due by May 18, 2018. Manomet is a certified service provider and will be working with communities in southeastern Massachusetts to assess risk and plan solutions. 

2018-04-27 16:00