Coastal Habitats Vulnerable to Climate Change

Coastal marsh within the Sandy Hook Bay estuary. Photo: NOAA Fisheries/Jessie Murray

A recent study assessing the vulnerability of coastal habitats to climate change in the northeast United States finds salt marshes, shellfish reefs, deep-sea corals, seagrasses, kelp, and intertidal habitats among the most vulnerable—these are also the habitats most at risk from degradation due to coastal development and pollution.

Marking a first-of-its-kind assessment, NOAA Fisheries and partners examined the impact of climate-driven changes on 52 marine, estuarine, and riverine habitats from the Maine-Canadian border south to Cape Hatteras, NC. It also considered non-climate factors, such as coastal development and pollution.

This assessment complements the 2016 Northeast Fish and Shellfish Climate Vulnerability Assessment, and other fish stock, protected species, and fishing community climate vulnerability assessments. The results are intended to guide research on possible climate impacts on habitats, and help decision-makers consider how to prepare for and respond to climate-related changes.

Winter flounder in eelgrass habitat (NOAA photo).

Winter Flounder

The 2016 Northeast assessment ranked winter flounder as very highly vulnerable to climate change. This is due to low stock status in the southern part of its range and declining population productivity associated with increased nearshore temperature. The new assessment highlights that habitats important to winter flounder, including submerged aquatic vegetation and tidal wetlands, are vulnerable to higher air and water temperature, sea level rise, and habitat fragmentation. The high climate vulnerability of these habitats, and high dependency of winter flounder on these habitats, suggests a potential critical nexus of climate vulnerability for this species.

Informing Decisions

The assessment highlights the importance of prioritizing habitat protection and restoration to support resilience and adaptability to climate change. Understanding how climate change will impact coastal and marine habitats is necessary to inform decisions about habitat conservation and restoration, fisheries management, and coastal and offshore planning. The publication includes detailed narratives describing the primary drivers of climate vulnerability for each of the habitats in the assessment.

The Study: Farr ER, Johnson MR, Nelson MW, Hare JA, Morrison WE, Lettrich MD, et al. (2021) An assessment of marine, estuarine, and riverine habitat vulnerability to climate change in the Northeast U.S. PLoS ONE 16(12): e0260654.

A low-to-no snow future?

Montana’s Madison Range (W. Tilt)

While La Niña has thankfully delivered a few big, early-season snowstorms to parts of the West, anthropogenic climate change is decreasing seasonal snowpacks around the world. For the western United States this poses potentially catastrophic consequences on water resources, given the region’s long-held reliance on snowpack for water supply.

In a recent study, A low-to-no snow future and its impacts on water resources in the western United States, a group of researchers have examined the changes and trickle-down impacts of snow loss in the western United States where snow water equivalent declines of ~25% are predicted by 2050. Among the study’s key points:

•  Mountain snowpacks in the western United States have historically acted as large, natural reservoirs of water; yet, they are now harbingers of a changing climate through their signaling of a low-to-no snow future.

• Diminished and more ephemeral snowpacks that melt earlier will alter groundwater and streamflow dynamics.

• Low-to-no snow will impose a series of cascading hydrologic changes to the water–energy balance, including vegetation processes, surface and subsurface water storage and, ultimately, streamflow that directly impacts water management. 

• A re-evaluation of long-standing hydroclimatic stationarity assumptions in WUS water management is urgently needed, given the impending trickle-down impacts of a low-to-no snow future.

• Co-production of knowledge between scientists and water managers can help to ensure that scientific advances provide actionable insight and support adaptation decision-making processes that unfold in the context of significant uncertainties about future conditions.

While recognizing the difficulty in determining the future direction of seasonal snowpacks, these predicted changes need to be integrated into water management practices now. Through proactive implementation of soft and hard adaptation strategies, there is potential to build resilience to extreme, episodic and, eventually, persistent low-to-no snow conditions.

The Study: A low-to-no snow future and its impacts on water resources in the western United States. Erica R. Siirila-Woodburn, Alan M. Rhoades, Benjamin J. Hatchett, Laurie S. Huning, Julia Szinai, Christina Tague, Peter S. Nico, Daniel R. Feldman, Andrew D. Jones, William D. Collins & Laurna Kaatz. Nature Reviews Earth & Environment volume 2, pages 800–819 (2021).

More: A future with little to no snow? What that means for the West and its rivers. Tara Lahan. Hatch

Turning Methane into Fishmeal

Farmed Tilapia. Photo courtesy of ZME Science

Turning leaked methane into fishmeal would turn a profit while helping the environment. The issue of methane pollution might become an asset in the future, thanks to new technology that can transform this potent greenhouse gas into fish food.

Approaches to converting methane into fishmeal have already been developed, the authors note, but the economic uncertainty during the pandemic has prevented its use to promote food security on any meaningful scale. The new study analyzes the method’s economic viability today. The main takeaway of the research is that methane-to-fishmeal conversion is economically feasible for certain sources of the gas and that other sources can be made profitable with certain improvements.

The approach can also be of quite significant help against climate change, the team adds, and is capable of meeting all the global demand for fishmeal, further reducing the strain we’re placing on natural ecosystems.

“Industrial sources in the U.S. are emitting a truly staggering amount of methane, which is uneconomical to capture and use with current applications. Our goal is to flip that paradigm, using biotechnology to create a high-value product.”

— Sahar El Abbadiae, Lead Author

Read “Displacing fishmeal with protein derived from stranded methane” published in Nature Sustainability.

The public prefers climate carrots to climate sticks

New research suggests that people’s preferences aren’t driven by self-interest or even politics; rather they’re driven by perceived effectiveness

By Sarah DeWeerdt, Anthropocene, November 16, 2021

People prefer climate policies that use incentives rather than disincentives – but are more tolerant of disincentives that target businesses rather than individuals, new research suggests.

The finding comes from a series of studies that dig into public opinion about whom climate policies should target, what changes those policies should aim for, and how such policies should exert their influence.

Knowing what kind of climate policies people will support and why is important because, well, without public support climate policies can’t actually be implemented. After all, communities where climate concern is high have voted down climate policies endorsed by experts in the past.

Yet few studies have taken a systematic look at how people mentally balance the benefits and harms of different policies, and why people support some climate policies and not others.

World's Coral Reef Decline with Rising Sea Temperature

Great Barrier Reef, Australia (photo: Wise Hok Wai Lum, Wikimedia)

An international analysis of coral reefs found a global loss in reef area of 14 percent since 2009 – about 4,517 square miles – as rising sea surface temperatures take their toll.

The largest analysis of global coral reef health ever undertaken, “Status of Coral Reefs of the World: 2020,” documents the loss drawing on data from 12,000 sites in 73 countries between 2009 and 2018. The report, the sixth edition produced by the Global Coral Reef Monitoring Network (GCRMN), provides the most detailed scientific picture to date of the toll elevated temperatures have taken on the world’s reefs.

According to a statement by network scientists:

“Corals reefs across the world are under relentless stress from warming caused by climate change and other local pressures such as overfishing, unsustainable coastal development and declining water quality.

“An irrevocable loss of coral reefs would be catastrophic. Although reefs cover only 0.2 per cent of the ocean floor they are home to at least a quarter of all marine species, providing critical habitat and a fundamental source of protein, as well as life-saving medicines. It is estimated that hundreds of millions of people around the world depend on them for food, jobs and protection from storms and erosion.

“However, the report also found that many of the world’s coral reefs remain resilient and can recover if conditions allow, providing hope for the long-term health of coral reefs if immediate steps are taken to stabilize emissions to curb future warming.”

Blue Carbon in Marine Protected Areas

NOAA’s Office of National Marine Sanctuaries has released a two-part Conservation Science Series: Blue Carbon in Marine Protected Areas. These reports describe how blue carbon ecosystems help mitigate climate change by sequestering and storing atmospheric carbon. 

Blue carbon ecosystems mitigate climate change by removing carbon dioxide from the atmosphere and transporting it into sediments or deep waters, where it can remain indefinitely if undisturbed. Accounting for these processes, and how they can help to achieve global carbon mitigation and emission reduction goals, is an emerging area of focus for marine protected area management. 

Led by Greater Farallones National Marine Sanctuary, with support from the Greater Farallones Association, Part 1 of a series seeks to inform and guide MPA managers in the assessment, protection, and management of blue carbon habitats and processes. Part 2 of this series, focuses on a case study for Greater Farallones National Marine Sanctuary.

Among the findings:

“This is the first assessment of multiple blue carbon sequestration processes in a U.S. federal MPA, with the primary purpose of informing one of the nation’s largest MPAs in its management decision-making. The carbon storage and annual sequestration for two coastal blue carbon habitats, seagrass and salt marsh, and two oceanic carbon sequestration processes, kelp export and dead whale falls, were assessed within the boundaries of the sanctuary using regional and site-specific data. These processes have the potential to sequester 4,950 megagrams of carbon (MgC) each year (or 18,150 metric tons CO2 equivalent), which is valued at $925,650 in societal benefit annually and is 140 times the amount of CO2 that is emitted from annual site operations. Whale falls account for roughly 60% of this annual sequestration; salt marsh, seagrass, and kelp account for roughly equal parts of the remaining 40%, though annual sequestration by the region’s kelp forests have declined by 99.7% from 2008 to 2019. Sanctuary coastal blue carbon habitats currently hold approximately 175,000 MgC in their sediments, which, if destroyed, could release approximately 643,000 metric tons of CO2, or the equivalent of adding 140,000 vehicles to the road for one year.”

Pathways for carbon sequestration by seagrass, salt marsh, and mangroves. Carbon is captured by the absorption of dissolved inorganic CO2 and fixation of carbon into the plant tissues, and sequestration into woody biomass and sediments. Image source: Clarifying the role of coastal and marine systems in climate mitigation, Howard, J et al, Frontiers in Ecology and the Environment (2017).

What Climate Change Means to the Greater Yellowstone

As one of the last remaining large, nearly intact ecosystems in the northern temperate zone of the world, the Greater Yellowstone Area (GYA) lays claims to many superlatives. For the angler, notably, it is arguably flyfishing central and the headwaters of the west, giving rise to the Green, Madison/Gallatin, Snake, Wind River/Big Horn, and the Yellowstone rivers. And it’s the focus of the recently released Greater Yellowstone Climate Assessment.

Instead of being bound by the political and jurisdictional boundaries that typically define such efforts, the Greater Yellowstone Climate Assessment is the first of its kind to consider climate change impacts at the ecosystem-scale, focusing on the six major watersheds within the region.

Authored by researchers at the US Geological Survey, Montana State University, University of Wyoming, and others, the collaborative report brings the best available science to the issue of climate change with a focus on water.  The assessment explores past trends in climate change, current conditions, and projected future changes, taking the often abstract and distant concepts associated with climate science and bringing them into focus at the regional level.

The following table summarizes data on temperature, snowfall, and peak stream flow for the 1950-2018 historical period and projected changes to 2100 by hydrological unit, i.e., watersheds.

Some Findings

Temperature

• GYA average temperature for 2001-2020 is probably as high or higher than any period in the last 20,000 years, and likely higher than previous glacial and interglacial periods in the last 800,000 yr. Meteorological records since 1950, averaged across the GYA, show that mean annual temperature in the GYA has increased by 2.3°F (1.3°C) at a rate of 0.35°F (0.20°C) per decade. [high confidence].

Precipitation

• The geologic record indicates that decade-long periods of low precipitation have occurred in the past 1200 yr. These dry periods were times of reduced snowpack, more fires, lower streamflow, and establishment of trees above present tree line. Since 1950, average precipitation across the GYA has not changed significantly and remains near 15.9 inches (40.5 cm) with year-to-year variability of 2.2 inches (5.6 cm) [high confidence]. Precipitation has increased in spring and fall, by 17-23% in April and May, and 42% in October. It has declined by 17% in June and 11% in July. [high confidence].

• As climate has warmed, mean annual snowfall in the GYA has declined. Much of the snowfall decline has occurred in spring when warming was greatest. [high confidence]. Measurable snowfall has become rare in June and September as the snow-free season has lengthened.

Streamflow and runoff

• Streamflow records in the GYA since the early 20th century allow comparison of current trends to past events such as the 1930s Dust Bowl drought. Since 1925, the timing of peak flow has shifted earlier in the year by 8 days (range of 1-15 days in the watersheds), extending the length of the water-limited warm season. [high confidence].

• The shift in the timing of peak streamflow since 1970 has been approaching the early timing that occurred during the 1930s Dust Bowl drought. The recent shift, however, is caused by rising spring temperatures that melt snow earlier, whereas during the Dust Bowl drought it was caused by a year-round decline in precipitation.

• In selected free-flowing rivers within the GYA, annual flows since the mid-20th century have decreased by 3-11%, spring flows have increased by 30-80%, and summer and fall minimum flows have declined by 10-40% (table below).

Monthly mean streamflow in free-flowing rivers in the GA from 1985-2018 (left column) and the percent changes from the 1950-1984 average (right column).

The data show a future where significant changes will be experienced at mid- and high elevations where runoff from snowmelt increases in spring (March through May) and decreases in summer (June through August).  

Stakeholder Concerns

The assessment explores present and future implications for agriculture, energy, wildfire, and winter recreation in the region. Interviews with stakeholders yielded important insights into the climate realities faced by local communities with the following key findings emerging from these conversations:

•  Water issues are at the core of climate change impacts in the GYA. Communities and managers will continue to face challenges like drought and shifts in seasonal water cycles in the future.

• Participants’ understanding of and response to climate change is driven more by their background (stakeholder group) than their location (watershed).

• A pressing need exists for a climate information hub that is comprehensive, collaborative, accessible, and useful to experts and the public alike.

• For the most part, meaningful policy to address and adapt to climate change is lacking in the GYA.

• By addressing water issues like availability and quality in future climate adaptation work, we stand to have positive impacts on myriad other conditions including wildlife habitat, fisheries health, and the economy of local communities.

 The assessment documents changes that have been observed and projects what the changes may be in the future. Now, rather than spending time arguing about the origins of climate change or who to blame, we can hopefully shift to what can be done to respond, to build climate resiliency in fisheries management, water use, and agricultural practices.

Why the Market for ‘Blue Carbon’ Credits May Be Poised to Take Off

A seagrass meadow near Atauro Island, Timor-Leste. Paul Hilton, Conservation International

Nicola Jones, YaleEnvironment360

Seagrasses, mangrove forests, and coastal wetlands store vast amounts of carbon, and their preservation and restoration hold great potential to bank CO2 and keep it out of the atmosphere. But can the blue carbon market avoid the pitfalls that have plagued land-based programs?

Off the shores of Virginia, vast meadows of seagrass sway in the shallow waters. Over the past two decades, conservation scientists have spread more than 70 million seeds in the bays there, restoring 9,000 acres (3,600 ha) of an ecosystem devastated by disease in the 1930s. The work has brought back eelgrass (Zostera marina) — a keystone species that supports crustaceans, fish, and scallops, and is now absorbing the equivalent of nearly half a metric ton of CO2 per hectare per year.

Now, the Virginia Nature Conservancy is aiming to turn those tons into carbon credits that it can sell for cash.