Diving Deeper into the Impacts of Marine Heatwaves on the Blue Economy

As climate change accelerates, marine heatwaves (MHWs) are becoming more frequent, leading to significant disruptions in marine ecosystems and ocean-based activities. The CAREHeat project, funded by the European Space Agency (ESA), is at the forefront of studying these extreme events, advancing our understanding of their causes, and assessing their socio-economic and ecological impacts.

One of CAREHeat's central objectives is to evaluate how MHWs affect biodiversity, ecosystem services, and critical industries like aquaculture and fisheries. Recent results from the project highlight the impacts of MHWs at aquaculture farms in Portugal and Norway, and Marine Protected Areas (MPAs) in Italy, underscoring the importance of collaboration between science and stakeholders.

Evaluating the Impacts of Marine Heatwaves

MHWs are localised, persistent periods of unusually warm seawater temperatures that disrupt ocean ecosystems and threaten marine biodiversity. They impact various species differently, depending on their mobility, physiology, and age. 

To address these challenges, CAREHeat has focused on assessing MHW effects on aquaculture species in Portugal and Norway and several species in Italian MPAs. Collaborating closely with farmers and MPA managers, CAREHeat uses data to develop impact assessment models and foster a dialogue with stakeholders, ensuring scientific insights are relevant to real-world scenarios.

The Role of Earth Observation and Geospatial Climate Data

CAREHeat has demonstrated the value of Earth Observation (EO) and geospatial climate data for decision-making in the context of MHWs. Stakeholders have shown interest in incorporating these data into their operations, especially when local-specific indicators inform planning. 

However, the use of geospatial products remains limited. Many users prefer simpler formats for early warning systems and may lack the capacity to select suitable datasets. CAREHeat emphasises ongoing collaboration between scientists and stakeholders to refine the use of geospatial data.

Challenges in Understanding and Measuring MHWs

Despite growing awareness of MHWs, many users struggle to understand their definition and distinction from absolute temperature changes. CAREHeat's engagement with stakeholders revealed that continuous dialogue is essential to ensure that scientific terminology resonates with practical needs. 

This communication aims to align scientific objectives with user expectations and enhance the uptake of MHW detection tools like the CAREHeat MHW Atlas.

Data Scarcity and Biological Impacts

A significant challenge in the impact assessment studies is the limited availability of biological data compared to the wealth of EO data in the CAREHeat MHW Atlas. Sparse biological data collected from non-controlled populations hampers the statistical significance of findings, highlighting the need for consistent monitoring of biological parameters. 

CAREHeat recommends incentivizing the sharing of anonymized data to build a more robust dataset for future studies.

Added Value Towards Effective Mitigation Strategies

CAREHeat’s impact assessment results are valuable for both scientific and practical applications. Users in aquaculture and MPA case studies are keen to use climate data to mitigate the effects of MHWs on marine species. 

High accuracy between satellite-based MHW detection and in-situ data demonstrates the reliability of CAREHeat’s MHW Atlas for real-world applications. However, greater support is needed to make geospatial data accessible to decision-makers.

Expanding the Impact of CAREHeat’s Results

Insights from CAREHeat's impact assessment studies pave the way for future exploitation. The project has identified several key areas for future work:

• Generalisation of Findings
  Expanding research to other locations and species will enhance understanding of MHW effects on different ecosystems and industries.

• Development of Predictive Models
  Creating temporal predictive models for MHWs will enable stakeholders to better anticipate events.

• Increased Collaboration with Stakeholders
  Promoting collaboration between researchers and users will foster the uptake of EO-based tools, allowing informed decisions based on the best available data.

   

By advancing knowledge on the ecological and socio-economic impacts of MHWs, CAREHeat is contributing to effective mitigation strategies that protect marine biodiversity and sustain vital ocean-based activities like aquaculture and fisheries. As MHWs continue to threaten marine ecosystems, CAREHeat's work will serve as a critical foundation for future research and action.

Conceptual Framework of CAREHeat WP5000 activities: Aquaculture and Marine Protected Areas Impact Assessment

Disseminating New MHW Knowledge with CAREHeat’s Scientific Publications

The CAREHeat project has led to significant research advances, contributing to a deeper understanding of Marine Heatwaves (MHWs) and their impact on ecosystems. Here are some key publications that resulted from the project:

• Marine Heatwaves in the Mediterranean Sea: A Literature Review
  Synthesises research on marine heatwaves, discussing their driving mechanisms, impacts, and the need for enhanced monitoring and forecasting capabilities.
   
• Detection, characterization and trends of Marine Heat waves in the global warming scenario: the CAREHeat Project
  Outlines the multidisciplinary approach used by the CAREHeat project to detect and analyse MHWs, leveraging satellite Earth observations and advanced technologies. It introduces the CAREHeat Global Atlas, which tracks MHW variability from 1981 onwards and assesses the impacts on marine ecosystems.
   
• How to Better Characterize Marine Heatwaves
  Discusses the CAREHeat project's efforts to improve MHW detection by revisiting current methodologies and applying machine learning to reconstruct 4D temperature fields. These developments allow for a more detailed analysis of how MHWs propagate through ocean depths and their effects on ecosystems.
   
• Has the Frequency of Mediterranean Marine Heatwaves Really Increased in the Last Decades?
  Addresses the critical issue of using long-term SST baselines to detect MHWs. It examines the influence of climate change on MHW frequency and discusses the evolution of the 2022 event, one of the most prolonged and intense MHWs in recent history.
   
• Evolution of Marine Heatwaves in Warming Seas: The Mediterranean Sea Case Study
  Provides a comprehensive analysis of MHWs, identifying an intensification in their frequency, intensity, and duration over four decades. Includes a catalogue of the most significant MHWs, such as the exceptionally long and intense event of 2022.
   
• Record-breaking Persistence of the 2022/23 Marine Heatwave in the Mediterranean Sea
  Documents the longest marine heatwave recorded in the Mediterranean over the past four decades, emphasizing the role of atmospheric conditions in driving warm anomalies.
   
• Phytoplankton Spring Bloom Inhibited by Marine Heatwaves in the North-Western Mediterranean Sea
  Highlights the significant impact of MHWs on phytoplankton spring blooms, noting the substantial reduction in carbon biomass due to increased ocean stratification, which limits nutrient supply.
   
• Extreme Events Contributing to Tipping Elements and Tipping Points
  Highlights how weather and climate extremes influence tipping elements and trigger tipping points in the Earth System, emphasizing examples like Amazon rainforest dieback, Atlantic circulation collapse, and coral reef degradation, while underscoring the need for Earth observations to understand these links and improve predictive models.
   
• Opportunities for Earth Observation to Inform Risk Management for Ocean Tipping Points
  Evaluates the role of Earth Observation in addressing risks linked to ten major ocean tipping elements, highlighting the need for long-term data, integration within situ observations, and alignment with models to enhance monitoring, early warnings, and climate model development.

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