9 Comparison Report
This chapter is a comparison between historical estimates of global fishing emissions to those discovered by Global Fishing Watch (GFW) and emLab. There are two sections. The first is a report detailing what our team found during our project and comparing that to historic estimates, particularly the year 2016. The second works as living report that will automatically update as new data is uploading to the pipeline.
9.1 Report
9.1.1 Introduction
The carbon footprint of marine fisheries plays a crucial role in global ocean sustainability. Our study examines CO₂ emissions from fishing activities, incorporating FAO data, Sea Around Us estimates, and original calculations derived from AIS and Sentinel-1 satellite data. By integrating satellite-based tracking, we aim to enhance emissions estimates, particularly for vessels that do not use AIS, which may have been underrepresented in previous assessments. This research builds upon previous studies, including Fuel Use and Greenhouse Gas Emissions of World Fisheries by Parker et al. (2018), which used a global fuel-based approach to estimate CO₂ emissions, and Global Trends in Carbon Dioxide (CO₂) Emissions from Fuel Combustion in Marine Fisheries from 1950 to 2016 by Greer et al. (2018), which reconstructed effort-based emissions calculations. By incorporating an updated perspective that connects vessels to fishing based on tracking, our study provides a refined analysis of the emissions footprint of global fisheries
9.1.2 Background
The Sea Around Us study (Greer et al. 2018), estimated CO₂ emissions from marine fisheries using a bottom-up reconstruction approach based on fishing effort data rather than reported catch alone. They did this based on:
Fishing Effort Data - They reconstructed the number of fishing vessels per country, categorized by fleet type, gear, length class, and motorization. Engine capacity and days at sea were used to estimate total effort.
Fuel Consumption Estimates – They calculated fuel use based on engine power (kW), fuel efficiency trends, and hours of engine operation per fishing trip.
CO₂ Emissions Calculation – They applied specific fuel consumption rates and emissions factors to estimate total CO₂ emissions from fuel combustion.
Comparison with Other Studies – Their estimates included both reported and unreported fisheries, leading to a higher total CO₂ emissions figure compared to previous studies that relied on catch-based fuel use intensity.
The Fuel Use study (Parker et al., 2018) estimated CO₂ emissions using a fuel-based approach rather than relying on catch data or reconstructed fishing effort. Here’s how they did it:
Global Fisheries Energy Use Database (FEUD) – They compiled data on fuel consumption from various fisheries worldwide, categorizing vessels based on gear type, species targeted, fleet characteristics, and region.
Fishing Effort Data – They estimated fishing effort based on engine power (gross tonnage) and days at sea, using sources like FAO, the European Union, and regional tuna-management bodies.
Fuel Use Intensity (FUI) – They assigned fuel consumption rates to different fisheries based on past case studies and adjusted them using weighted averages.
CO₂ Emissions Calculation – They applied fuel combustion emission factors and included non-fuel emissions such as vessel construction, refrigerant loss, and gear production to estimate total CO₂ emissions.
Comparison with Agriculture & Livestock – They contextualized fishery emissions by comparing them to emissions from land-based food production, highlighting the relatively lower carbon footprint of small pelagic fisheries compared to livestock.
9.1.3 Results
Comparing Global Trends in Carbon Dioxide (CO₂) Emissions from Fuel Combustion in Marine Fisheries from 1950 to 2016 by Greer et al. (2018) The Greer et al. (2018) study analyzed global CO₂ emissions from small-scale and industrial fisheries between 1950 and 2016, using Sea Around Us catch and effort data to estimate emissions trends. Their findings showed that industrial fishing emitted 159 million tonnes of CO₂ in 2016, a sharp increase from 39 million tonnes in 1950, while small-scale fisheries emitted 48 million tonnes, compared to 8 million tonnes in 1950. They also assessed emissions intensity, determining that industrial fishing produced 2.0 tCO₂∙tcatch−1, meaning 2 tonnes of CO₂ were emitted for every 1 tonne of fish caught, whereas small-scale fisheries had an intensity of 1.8 tCO₂∙tcatch−1. In our study, we estimated total CO₂ emissions from marine fisheries in 2016 at 146 million tonnes, about 9% lower than industrial fishing, with an emissions intensity of 1.87 tCO₂∙tcatch−1 using FAO data, and 1.49 tCO₂∙tcatch−1 using Sea Around Us (SAU) data
These differences in emissions estimates and intensities likely arise from variations in data sources and methodology. We used FAO and SAU catch data but also incorporated AIS and Sentinel-1 satellite tracking, which allowed for more precise emissions estimates by identifying vessels that do not use AIS. This approach may have resulted in lower emissions intensity compared to the effort-based reconstruction used by Sea Around Us, which estimated fishing effort based on fleet characteristics rather than direct vessel tracking. Additionally, Sea Around Us separated industrial and small-scale fisheries, leading to higher total emissions estimates for industrial fleets, whereas we did not explicitly differentiate these categories in our analysis. The methodological differences in tracking fuel consumption also played a role, as Sea Around Us estimated fuel use based on engine power, efficiency trends, and fishing effort, which may have yielded a higher intensity figure for industrial fleets compared to our direct tracking approach.
Lastly, The Greer et al. (2018) study also compared total catch (tonnes) to total CO₂ emissions from 1950-2011 as shown in Figure 2. (Greer et al., 2018). According to the study, the graph shows “CO₂ emissions in both sectors continued to increase after the mid-1990s, despite declining global catches” (Greer et al., 2018)
Our study’s analysis of Sea Around Us (SAU) catch data found a total global catch of 101,194,604 tonnes in its most recent year, 2019, compared to 108,000,000 tonnes in 2011 as reported by Greer et al. (2018). These numbers are even lower, 80,000,000 tonnes when looking at FAO catch. This decline aligns with the broader consensus that global fish catch has been decreasing since the late 1990s, when wild fish landings seem to have peaked. According to the Food and Agriculture Organization (FAO, 2024), total seafood production has increased due to aquaculture expansion, whereas wild capture fisheries have experienced stagnation or decline possibly due to factors such as overfishing, habitat degradation, and climate-related impacts. The lower catch estimate observed in our study supports the trend that many fisheries are struggling to maintain previous harvest levels, reinforcing concerns about the sustainability of marine resources.
In 2019, our analysis estimated 146 million tonnes of total emissions, whereas Greer et al. (2018) reported 159 million tonnes for the industrial sector alone. This discrepancy makes it difficult to determine whether emissions are genuinely rising or if the variation stems from differences in methodologies and underlying assumptions. Differences in data sources, estimation techniques, and classifications of fishing activity may contribute to these variations, highlighting the complexity of accurately assessing global emissions trends. Comparing Fuel Use and Greenhouse Gas Emissions of World Fisheries by Parker et al. (2018) Parker et al. (2018) estimated that global fishing fleets burned 40 billion liters of fuel in 2011, emitting 179 million tonnes of CO₂-equivalent (CO₂e) greenhouse gases into the atmosphere. Despite relatively stable fish landings, emissions from the industry increased by 28% between 1990 and 2011. Additionally, the study found that the average emissions per tonne of landed fish rose by 21%, reaching 2.2 tonnes CO₂e per tonne landed in 2011. The primary driver of this increase was the expansion of fuel-intensive crustacean fisheries, which had an emissions intensity of 7.9 tonnes CO₂e per tonne landed, significantly higher than small pelagic fisheries (0.2 tonnes CO₂e per tonne landed).
Our study does not extend back to 2011 but examines CO₂e emissions from 2016 to 2024 using 20-year Global Warming Potential (GWP) factors. We observed a notable 52.6% increase in emissions from 2016 to 2023, rising from 148 million tonnes CO₂e to 226 million tonnes CO₂e, a much steeper rate of increase compared to the 28% growth from 1990 to 2011 reported by Parker et al.
Furthermore, emissions per tonne of landed fish in our study increased from 1.86 tonnes CO₂e in 2016 to 2.47 tonnes CO₂e in 2022, representing a 32.8% increase over six years. This is based on FAO catch since SAU catch only ranges from 2016-2019. By 2022, our emissions intensity exceeded the 2011 global average of 2.2 tonnes CO₂e per tonne landed, highlighting a possible shift toward more fuel-intensive fishing methods, similar to trends observed in Parker et al.’s study. If this pattern persists, emissions from global fisheries could more than double by 2032, underscoring the urgent need for improved fuel efficiency and sustainable fishing practices to mitigate the environmental impact of the industry.
9.2 Future
9.2.1 What do emissions look like now?
| Year | Total CO2 MT | Total Catch (Tonnes) | Emissions per Catch | CO2 Percent Change | Catch Percent Change |
|---|---|---|---|---|---|
| 2016 | 146238920 | 79,586,274 | 1.84 | - | - |
| 2017 | 130148861 | 82,775,510 | 1.57 | -11% | 4% |
| 2018 | 139017519 | 85,508,559 | 1.63 | 7% | 3% |
| 2019 | 145326671 | 81,492,928 | 1.78 | 5% | -5% |
| 2020 | 146114275 | 79,632,775 | 1.83 | 1% | -2% |
| 2021 | 158836613 | 81,612,999 | 1.95 | 9% | 2% |
| 2022 | 199511890 | 81,075,117 | 2.46 | 26% | -1% |
| 2023 | 223914218 | 0 | Inf | 12% | -100% |
| 2024 | 213189276 | 0 | Inf | -5% | - |