How has climate changed in the U.S. Northeast - and how might it change in the future?

Three big climate impacts we have experienced are:

Hotter Temperatures 

More Rain & Severe Storms

Sea Level Rise

 Photo: Cracked Mud: California Drought, (c) Tyler Bell, (CC BY 2.0)

  Hotter Temperatures:

Figure: Over the coming century, Massachusetts climate is projected to warm, giving it a climate similar to states located in the US South. Yellow shows projected warming in a lower-emissions scenario and red is for a higher-emissions scenario. (Source: Union of Concerned Scientists, 2007).

• What we’ve seen:
  • Temperatures increased by 1°C or 2°F since 1850 (2021 IPCC Report)
  • Cities tend to be 1-7°F hotter than surrounding areas because of high density and their many dark, hard surfaces (like asphalt)
  • Extreme Heat events are 3 to 5 times as likely to occur as they used to be 
  • (2021 IPCC Report)

• Future Changes:

  • Increases of ~3 to 12°F over next century (depends on uncertainty & emissions levels)
  • Increase in heat waves - number of days over 90°F
  • Extreme Heat Events will occur 5 to 13 times as often as they used to (2021 IPCC Report)

 More Rain & Severe Storms:

Photo: Damage to Vermont Road from Tropical Storm Irene, 2011 (c) U.S. Army Corps of Engineers (CC BY 2.0).

• What we’ve seen:

• • Over the last 50 years in the US Northeast, there was an increase of over 50% in the amount of rain that fell in the most extreme (top 1%) of events & an over 90% increase in the number of ‘5-year’ rain events
  • The frequency and severity of hurricanes may also have increased since the 1970s due to factors like increased sea surface temperature

• Future changes:
  • The frequency of heavy downpours is projected to increase; and the most intense storms will likely also increase in frequency and severity
  • Extreme Precipitation is expected to increase by 7% in the coming decades (2021 IPCC Report)
  • But there’s also an increased risk for drought in the summer and fall

 Sea Level Rise:

Photo: Damage in Seaside Heights, New Jersey from Superstorm Sandy, 2012 (c) Anthony Quintano, (CC BY 2.0)

According to the 2021 IPCC Report:

• What we’ve seen:

  • Average global sea level has risen 0.2 meters or 8 inches over last century (2021 IPCC Report)

  • The global sea level has risen faster over the last 100 years than any of the proceeding 3000 years (2021 IPCC Report)

• Future changes:

  • A projected average increase of 1 to 4 feet by 2100, and up to 8 feet would be possible (depending on emissions and uncertainty)

  • The US Northeast is projected to have a higher-than-average rate of sea level rise

  • Much of sea level rise is locked in, even if emissions go down. (2021 IPCC Report) That's why adaptation is so important.

Want to learn more? Here are some useful resources:

• U.S. Global Change Research Program Climate Science Special Report (CSSR), June 28, 2017
• Northeast Regional Impacts, 2014 National Climate Assessment, US Global Climate Change Program
• Climate Change 2014 Synthesis Report: Summary for Policymakers, Intergovernmental Panel on Climate Change (IPCC) 
• Fourth National Climate Assessment, November 23, 2018