What are the challenges MPAs are facing to address climate change?

Jon C. Day

The potential economic, social, cultural and environmental costs of climate change in MPAs are immense. Here, we will provide a number of challenges facing MPA practitioners when it comes to climate change.

Key takeaways

Key takeaways

Reduce local stresses - Reducing local pressures (e.g., poor water quality, unsustainable fishing, dumping of marine dredge spoil) remains essential to protect habitats and species. By minimizing as many of these pressures as possible, you will help build resilience for your MPA to better cope with inevitable climate change.
Key takeaways

Leave no stone unturned - Undertake as many of the management actions outlined in Table 3 (or similar local actions) as possible.
Key takeaways

Support national and international policy development - Continue to strongly advocate for national and international action to achieve the Paris Agreement. To do this, you need to understand the global implications of climate change, and the global context in which your MPA exists
Key takeaways

Think globally, act locally - Strongly counter those who lament that because climate change is a global issue, it’s not worth investing time or money into local or small-scale solutions
Key takeaways

Walk the talk - MPA practitioners, along with their families, friends and work colleagues, need to reduce their own GHG emissions

Where in the MPA lifecycle?

What's this about

Climate change Biodiversity Resilience Management effectiveness Cumulative impacts

Good for ...

MPA managers Evaluating progress MPA planner Reducing user conflicts Planning new MPAs Government Civil society

Understanding the enormity of the challenges

MPA practitioners face a number of challenges when it comes to climate change. The effects of a changing climate are not the same everywhere – impacts vary between sectors and locations, and occur at different scales. Knowledge on the underlying processes also varies.

Physical impacts

What’s happening now, what’s expected in the next few decades, and the compounding climate stressors exacerbating climate change. (e.g., Table 1)
Social, economic and cultural consequences

The true costs of climate change, examples of diverse impacts, especially for coastal MPAs, the role of the media and public awareness.

How you address all these challenges depends on a range of factors including the ecological components within your particular MPA, its location and natural resilience, current and expected management approaches, and the adaptive capacity within the MPA. To realistically assess the capacity of your MPAs to adapt to climate stressors, you need to consider the available scientific and technical knowledge along with the actual management capability (e.g., resources, budget – see in the chapter “Which sciences, technologies and innovations are emerging?”).

These are examples of the current knowledge about climate change impacts on marine-related environments along with some likely expectations. The reality is that some of these stressors are directly impacting your MPA now, while others are likely to in the foreseeable future. While it’s important to understand the diverse range of possible impacts, you need to prioritize your management actions to build resilience to minimize the primary impacts, especially those happening right now.

Temperature trends (air and sea)

What’s happening now:

Impacts of marine heatwaves on multiple species (e.g., coral, seagrass, mangroves) including increased mass mortality events
Hotter sand on beaches affecting sex ratios of turtle hatchlings
Impacts on seabird breeding success (e.g., have to range further offshore to find food for chicks)
More intense cyclones/hurricanes
Loss of breeding grounds

What’s expected in the next few decades:

Reproductive processes of some species likely to be significantly impaired
Warming of upper layers of ocean leading to greater stratification in the water column, and less oxygen in upper layers (hypoxia or “dead zones”), especially in estuaries and coastal zones
Reduced mixing in the water column, affecting primary production and nutrient availability
Disproportionate heating in polar regions with major implications for regional climates
Increase in harmful algal blooms
Potential mass movement

Sea-level rise (SLR)

What’s happening now:

Wetland flooding due to SLR involving saltwater intrusion of aquifers and coastal agricultural soils
Greater damage from storm-surge flooding
Coastal erosion and inundation leading to loss of beaches; impacts for turtle nesting
Habitat loss impacting estuarine plants (e.g., mangroves) which normally provide coastal protection

What’s expected in the next few decades:

Millions of people exposed to coastal inundation and coastal flooding over different timeframes
SLR lags well behind temperature increases, so substantial long-term SLR will continue for centuries even if the temperature stabilizes

Changing oceanic currents

What’s happening now:

Changes in current flow patterns (intensity and direction)
Altered upwelling patterns

What’s expected in the next few decades:

Shifts in range and/or distribution (or expansion) of some species (generally to higher latitudes)
Effects on movement of young fish from spawning grounds to nursery areas

Changing wind patterns (direction, intensity)

What’s happening now:

Changes in wind direction and intensity influencing patterns of surface currents and wave heights

What’s expected in the next few decades:

Further increases in wind intensity and wave heights
Implications for island and coastal morphology and pollution pathways
Increased wind speeds across North America and Europe predicted to continue for another decade or longer

Increasing ocean acidification

What’s happening now:

Surface pH has decreased by 0.1 pH unit since pre-industrial times
More acidic seawater already impacting all marine organisms that use calcium carbonate for their hard structures for protection (e.g., corals, shells, shellfish, sea snails)
Steadily acidifying seas are decreasing reef carbonate accretion (growth) and increasing carbonate erosion (loss), so reef structures are disappearing
Changes in behaviour of non-calcifying organisms (some fish, e.g., clownfish, have decreased ability to detect predators in more acidic waters. Decreased pH levels also affect the ability of larval clownfish to locate suitable habitat.)

What’s expected in the next few decades:

Changes in ocean chemistry will increasingly affect the behaviour of non-calcifying organisms
Full impacts are unknown; even if reef-building organisms are able to build skeletons in more acidic waters, they may have to spend more energy to do so, impacting other activities like reproduction
Increase in erosion and dissolution of reef carbonates makes the prospect of dissolving reefs virtually certain for high levels of emissions
Risks associated with ocean acidification will essentially be irreversible on foreseeable human timescales

Changing precipitation trends

What’s happening now:

Increased and/or more intense precipitation has water quality impacts (e.g., increased sedimentation and pollution, and changes in salinity levels affecting aquatic organisms in inshore environments)

What’s expected in the next few decades:

Sediment supply may be altered if climate change results in the modification, construction or removal of sea defenses
Changes to rainfall seasonality and extreme weather events may affect water mixing and oxygen levels in areas of freshwater influence, such as estuaries

Scale mismatches and a feeling of ineffectiveness

Other than building resilience, MPAs alone can do very little about large-scale impacts such as ocean acidification (Doney et al., 2020), deoxygenation (Breitburg et al, 2018) and changing ocean currents (Voozen, 2020). These are global challenges that need global action, and that in turn requires political will at international and national levels (see in the chapter “What limitations and gaps can we find?”).

Given this, you may feel that climate change is too complex an issue, and that you cannot do anything worthwhile to address it within your MPA. However, the truth is far from that; Table 3 lists actions and strategies that can make a difference. Many small actions, if effectively implemented, can collectively have an impact: it’s important to remain optimistic while also being realistic.

Compounding pressures exacerbating climate change

Another key challenge is to understand the compounding pressures on your MPA and their cumulative effects, and to mitigate these. A range of pressures (e.g., unsustainable fishing practices, coastal development, tourism, land-use practices in coastal areas) can decrease the resilience of an MPA, making it more susceptible to climate impacts. Climate change is also likely to exacerbate impacts such as:

Disease
Invasive species
Toxic blooms
Changes in freshwater inflows
Storms
Habitat modification

The combined impacts of multiple stressors will be greater than the impact of an individual stressor. A healthy MPA is expected to be far more resilient to climate change than one that is already suffering from a multitude of stresses.

MPAs that no longer fit their original purpose

One consequence of climate change is that some marine organisms are now migrating to higher latitudes (Beaugrand et al., 2019; Pecl et al., 2017). Similarly, commercially important species such as tuna are changing their distribution, reducing the ability of fisheries to manage their populations (Hobday et al., 2009).

Some MPAs may become less effective over time as conditions change and new species begin to dominate compared to those originally managed or protected. Existing MPAs may need to be expanded or relocated to ensure they remain effective for protecting biodiversity (Alagador et al., 2014) (see Module 4 Considering climate change in MPA design Q&A and Module 4 Climate change uncertainty in planning and management Q&A).

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Social, economic and cultural challenges

For MPAs in small island developing states and those adjoining coastal areas, the social, cultural and economic challenges of climate change are enormous. Table 2 provides some examples.

It’s important that all stakeholders and rights-holders are aware of the realities of climate change for their MPA, which may mean countering misinformation. They also need to be pragmatic and realistic, understanding what may be locally worth doing and what might actually be wasted effort. For example, some small-scale efforts to replant corals are unlikely to withstand the next major bleaching event, especially in a shallow area with insufficient water exchange. While such efforts may contribute to raising awareness amongst a small group of volunteers, increasing public awareness of the implications of climate change (see Table 2) in the wider community might be a better use of time and resources in the wider community.

These are examples of social, economic, and cultural implications of climate change, especially for islands/coastal areas. Gradual, slow, chronic change could occur over years or decades, and sudden/abrupt/acute events could occur over hours or days.

Temperature trend (Air and/or water)

Fish staying lower in water column so harder to catch
Impacts on diets that rely on native animals (e.g., fish, turtle eggs)
Increase in communicable diseases (e.g., bacterial diarrhoea) and disease transmission
Greater likelihood of disease in farmed aquaculture
Harmful algae and jellyfish blooms may lead to fish kills and closures of shellfish harvesting areas

Timeframe: Gradual/slow/chronic change

Storm surge

Loss of life
Property damage
Infrastructure impacts

Timeframe: Sudden/abrupt/acute events

Extreme temperature events

Damage to island infrastructure (power, transport, water)
Health impacts (heat stress), especially for elderly
Impacts on labour productivity
Harder for students and/or workers to concentrate

Timeframe: Sudden/abrupt/acute events

Precipitation trend

Increase in mosquito-borne diseases (e.g., dengue) as well as waterborne infectious diseases (e.g., Salmonella)
Increased rates of melioidosis (associated with mud and pooled surface water)

Timeframe: Gradual/slow/chronic change

Intense precipitation events

Damage to houses and infrastructure (roads/bridges)
Landslides
Increase in injuries
May release pollutants currently locked in seabed sediments

Timeframe: Sudden/abrupt/acute events

Coastal erosion

Community displacement
Loss of historic or sacred sites

Timeframe: Gradual/slow/ chronic change

Sea-level rise (trend)

Inundation of burial sites or sacred sites
Inability to maintain the health of land and sea
Encroachment by brackish water
Impacts on physical and mental health

Timeframe: Gradual/slow/chronic change

Ocean acidification

Some traditional foods (e.g., shellfish) less available

Timeframe: Gradual/slow/chronic change

Storm intensity and frequency

Sustained wind damage over longer periods requiring repairs to infrastructure, especially offshore structures
More episodic river flows might cause nutrient pollution in nearshore environments
Increased storminess might necessitate reduced loads for some ships and/or route changes
Storm damage to aquaculture farms may increase farm escapes, with conservation implications for surrounding areas
Fishers caught out at sea in more intense storms

Timeframe: Sudden/abrupt/acute events

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