NHNRI Guide Banner

Climate Conditions and Projections

Climate change has already affected the normal variability in weather patterns in New Hampshire, and is projected to continue to signifi­cantly alter climate conditions in the future. The projected changes in the climate of New Hampshire over the next century will continue to impact our environment, ecosystems services, economy, and society in numerous ways. It is import­ant for municipalities to understand the risks posed by changing climate conditions, and how they relate to local natural resources and human health, as well as to the built environment. Increasing temperature, sea level rise, and variability in precipitation are the primary climate change-related hazards in the Northeast. These hazards may pose significant risks to natural resources and human communities, such as through heat waves, drought, flooding, and poor air quality. Recognizing the value of natural resources as “green infrastructure” in devising climate adaptation strategies is essential.

Air temperature, sea level, and the frequency and intensity of extreme precipitation events are projected to continue to increase into the future in New Hampshire. For example, since 1970, New Hampshire’s average maximum temperatures have warmed by 1.9˚F (annual) and 2.8˚F (winter). Annual precipitation has increased 7–20%. Tidal gauge data indicates relative sea level at Portsmouth has been rising at about 0.7 inches per decade over the past eight decades. By 2020–2099, we can expect more precipitation (annual averages will increase by 16–19%), a two- to three-fold increase in extreme precipitation events and more frequent and severe flooding. New Hampshire sea levels are expected to rise 0.6 – 2.0 feet by 2050 and 1.6 – 6.6 feet by 2100 (data from Climate Assessments for New England). 

Good decisions need to be made to help our society and our ecosystems adapt to a changing climate. By taking climate change effects into consideration in the NRI, communities and conservation groups can take steps to ameliorate the impacts of climate change. Protecting natural resources and the lands associated with them (forestland, farmland, wetlands, riparian areas) can ameliorate the effects of flooding resulting from more frequent and intense storms.

Climate change is discussed in each of the NRI components, where applicable. There are a number of climate change resources available for New Hampshire, listed below: