Introduction
Climate change affects the nation's precious living marine resources and the people, businesses and communities that depend on them. Climate-related changes such as ocean warming, sea level rise, drought, and ocean acidification are affecting the distribution and abundance of marine species in the Northeast US continental shelf ecosystem. Understanding the impacts of climate change is essential to reducing climate-related impacts on living marine resources and the people and communities that depend on them. The NOAA Fisheries Climate Science Strategy is part of a proactive approach to increasing the production, delivery, and use of climate-related information needed to fulfill NOAA's fisheries mandates. The Strategy is designed to be adapted and implemented through Regional Action Plans that focus on developing regional capabilities, partners, products and services. The Northeast Fisheries Science Center has a variety of research and monitoring efforts that help monitor, understand, and predict climate-related impacts on resources and resource-dependent communities.
See The Northeast Shelf: A Changing Ecosystem story map.
Learn more about the North East Regional Climate Action Plan
Drivers of climate change and variability
Climate has a profound effect on life in the oceans. In the northeastern US continental shelf ecosystem, drivers of climate change and variability originate from both natural and human activities and contribute to the physical, chemical, and biological variability of the ecosystem. Over the past two decades, ocean temperatures in the Northeast have risen faster than the global ocean. In particular, the Gulf of Maine has warmed faster than 99 percent of the world's ocean (see animation below).
Sea surface temperature anomaly comparing the Gulf of Maine to the global average from 1981 to 2017.
Recent studies show that much of this enhanced warming is caused by human activity. The main component of human activity contributing to climate change is the historical and ongoing emission of long-lived greenhouse gases. These gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2THE). Since the beginning of the post-industrial era in 1750, atmospheric concentrations of these gases have increased significantly due to human activities.
We also observe natural variations in the Earth's climate that affect the northeastern US continental shelf ecosystem. For example, large-scale climate oscillations in the North Atlantic Ocean are associated with North Atlantic Oscillation and Atlantic Multidecadal Oscillation. The location of the Gulf Stream is also linked to the ecosystem's climate and oceanography. A more northerly position of the Gulf Stream is associated with warmer waters in the region. Likewise, changes to Atlantic Meridional Traffic Overturn it may also affect the oceanography of the NES.
Projected Climate Change
The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment of projected global and regional ocean temperature change is based on global climate models that have relatively coarse (~100 km) ocean and atmosphere resolutions. In this ecosystem, the global climate models assessed by the IPCC do not simulate the regional circulation of continental shelf and slope waters. Furthermore, these coarse-resolution climate models cannot resolve the fine scale bathymetry in the north-east, such as deep gorges, channels and banks (eg Georges Bank), which affect regional traffic.
The NOAA Laboratory of Geophysical Fluid Dynamicsit is high resolution global climate model 2.6 simulates the regional oceanic circulation of the Northwest Atlantic shelf much better than the coarse-grained models evaluated by the IPCC. The atmospheric CO2 doubling response from this model shows that ocean floor temperature on the Northwest Atlantic shelf, particularly in the Gulf of Maine, is warming at a rate nearly two to three times faster than the low-resolution models. This enhanced heating is accompanied by an increase in salinity. This is due to a change in water mass distribution associated with the retreat of the Labrador Current and a northward shift of the Gulf Stream (see animations below). Both observations and the climate model demonstrate a strong relationship between a weakened Atlantic meridional overturning circulation and an increase in the proportion of warm-temperate gradient water entering the Northwest Atlantic shelf. Therefore, previous climate change projections for the Northwest Atlantic shelf may be too conservative and underestimate expected warming in the US Northeast continental shelf ecosystem.
Animation of Northwest Atlantic Ocean and shelf monthly salinity/temperature change under atmospheric CO2 duplication script from GFDL CM2.6. Monthly salinity and temperature from the model are averaged between 150–200 m (about 500–650 ft) depth to represent Slope Water intrusions into the northeast channel. Ocean depths greater than 150 meters are shown. CM2.6 monthly salinity and temperature run under an 80-yr flux of atmospheric CO2 increases by 1% per year so that it doubles by year 70.
Projected Impacts of Climate Change: Habitats
The majority of research on the historical and projected impacts of climate change on the northeastern US continental shelf ecosystem has focused on species distributions. Most of these studies use Northeast Fisheries Science Center fall and spring bottom trawl survey data to generate species distribution models (SDMs) for fish, sharks, and invertebrates. SDMs are compared with observations and future changes are then predicted using global climate models. Most of these studies have focused exclusively on species thermal habitat (a species' preferred temperature range) and ocean temperature change using only fall/spring data independent of fisheries. New research investigates other ocean variables besides ocean temperature. In addition, this new research it also uses data collected by fishery observers to construct SDMs throughout the year as opposed to only for fall and spring. Results, which can be viewed as interactive graphics heresuggest that temperature-only SDMs can capture climate vulnerability for key commercial and recreational species such as squid, American lobster, Atlantic cod, sea bass, striped bass, summer and winter squid.
