Impacts of climate change on marine fisheries sector

![Figure][1] In August 2009, the International Union of Physiological Sciences (IUPS) held its 36th Congress in Kyoto in the same convention centre where the historic Kyoto Protocol was drawn up 12 years earlier. The symbolism of this coincidence was not missed by Malcolm Gordon, the Chair of

氣候變遷與自然資源的經濟分析－以珊瑚礁、水資源為例

Scientists at NOAA's Hurricane Research Division recently analyzed the inner-core upper-ocean environment for 23 Atlantic, Gulf of Mexico, and Caribbean hurricanes between 1975 and 2002. The interstorm variability of sea surface temperature (SST) change between the hurricane inner-core environment and the ambient ocean environment ahead of the storm is documented using airborne expendable bathythermograph (AXBT) observations and buoy-derived archived SST data. The authors demonstrate that differences between inner-core and ambient SST are much less than poststorm, “cold wake” SST reductions typically observed (i.e., ∼0°–2°C versus 4°–5°C). These findings help define a realistic parameter space for storm-induced SST change within the important high-wind inner-core hurricane environment. Results from a recent observational study yielded estimates of upper-ocean heat content, upper-ocean energy extracted by the storm, and upper-ocean energy utilization for a wide range of tropical systems. Results from this analysis show that, under most circumstances, the energy available to the tropical cyclone is at least an order of magnitude greater than the energy extracted by the storm. This study also highlights the significant impact that changes in inner-core SST have on the magnitude of air–sea fluxes under high-wind conditions. Results from this study illustrate that relatively modest changes in inner-core SST (order 1°C) can effectively alter maximum total enthalpy (sensible plus latent heat) flux by 40% or more. The magnitude of SST change (ambient minus inner core) was statistically linked to subsequent changes in storm intensity for the 23 hurricanes included in this research. These findings suggest a relationship between reduced inner-core SST cooling (i.e., increased inner-core surface enthalpy flux) and tropical cyclone intensification. Similar results were not found when changes in storm intensity were compared with ambient SST or upper-ocean heat content conditions ahead of the storm. Under certain circumstances, the variability associated with inner-core SST change appears to be an important factor directly linked to the intensity change process.

The Arabian Gulf comprises one of the world's most unique and fragile marine ecosystems; it is susceptible to the adverse effects of climate change due to its shallow depth and its location within an arid region that witnesses frequent severe atmospheric events. To reproduce these effects in numerical models, it is important to obtain a better understanding of the region's sea surface temperature (SST) variability patterns, as SST is a major driver of circulation in shallow environments. To this end, here, empirical orthogonal function (EOF) decomposition analysis was conducted to investigate interannual to multi-decadal SST variability in the Gulf from 1982 to 2020, using daily Level 4 Group for High Resolution SST (GHRSST) data. In this way, three dominant EOF modes were identified to contribute the Gulf's SST variability. Significant spatial and temporal correlations were found suggesting that throughout the 39-year study period, SST variability could be attributed to atmospheric changes driven by the El Nio-Southern Oscillation (ENSO), Atlantic Multi-decadal Oscillation (AMO), and Indian Ocean Dipole (IOD) climate modes. Spatial and temporal analyses of the dataset revealed that the average SST was 26.7°C, and that the warming rate from 1982 to 2020 reached up to 0.59°C/decade. A detailed examination of SST changes associated with heat exchange at the air-sea interface was conducted using surface heat fluxes from fifth generation (ERA5) European Centre for Medium-Range Weather Forecasts (ECMWF). Despite the SST warming trend, the accumulation of heat during the study period is suggesting that there was an overall loss of heat (cooling). This cooling reverted into heating in 2003 and has since been increasing.

Late Pliocene to early Pleistocene astronomically forced sea surface productivity and temperature variations in the Mediterranean

Evidence of solar insolation and internal forcing of sea surface temperature changes in the eastern tropical Indian Ocean during the Holocene

Sea surface temperature (SST) variation in the Subei coastal waters, East China, which is important for the ecological environment of the Yellow Sea where Enteromorpha prolifera blooms frequently, is affected by the East Asian winter monsoon (EAWM), El Nino-Southern Oscillation (ENSO), and Pacific Decadal Oscillation (PDO). In this study, correlations between climatic events and SST anomalies (SSTA) around the Subei (North Jiangsu Province, East China) Coast from 1981-2012 are analyzed, using empirical orthogonal function (EOF) and correlation analyses. First, a key region was determined by EOF analysis to represent the Subei coastal waters. Then, coherency analyses were performed on this key region. According to the correlation analysis, the EAWM index has a positive correlation with the spring and summer SSTA of the key region. Furthermore, the Nino3.4 index is negatively correlated with the spring and summer SSTA of the key region 1 year ahead, and the PDO has significant negative coherency with spring SSTA and negative coherency with summer SSTA in the key region 1 year ahead. Overall, PDO exhibits the most significant impact on SSTA of the key region. In the key region, all these factors are correlated more significantly with SSTA in spring than in summer. This suggests that outbreaks of Enteromorpha prolifera in the Yellow Sea are affected by global climatic changes, especially the PDO.

The time-lag relationship between precipitation and sea surface temperature (SST) variations depends upon the time scale. The present study compares the relationship between precipitation and SST variations on three time scales (synoptic, intraseasonal, and interannual) during boreal summer in the North Indian Ocean and the western North Pacific region. On interannual time scale, higher SST is followed by more rain rate in the Arabian Sea, but less rain rate in the Philippine Sea. On intraseasonal and synoptic time scales, higher SST precedes more rain rate. It is shown that the precipitation perturbation following the SST perturbation is more robust in the Philippine Sea on interannual and intraseasonal variations and less robust in the Arabian Sea on synoptic variations. The increase of rain rate perturbation leads to a decrease of SST on all the three time scales. The SST change in response to precipitation perturbation is more robust in the Philippine Sea and the South China Sea than in the Arabian Sea and the Bay of Bengal on interannual and intraseasonal variations. The correlation between intraseasonal precipitation and SST variations tends to be stronger when SST is above than below 29 °C in the South China Sea and the Philippine Sea. The correlation between intraseasonal precipitation perturbation and precipitation-induced SST change displays a decrease with total rain rate in the Arabian Sea and the Bay of Bengal.

Marine ecosystems such as fishing grounds, biodiversity havens, carbon sinks, and coastal protectors have begun experiencing increased strains with the ever-mounting impacts of climate change. This work examines the problem using Earth and Planetary Science approaches, including satellite remote sensing, oceanographic modeling, and geochemical assessments of waters and sediments. We analyze changes such as the increase in biological productivity of living marine species, sea surface temperatures, ocean acidification, deoxygenation, and changes in marine currents. Through ecosystem service models, we also assess the sustainability of human populations, food security, and coastal resilience in regions impacted by climate change and the exacerbation of stressors on the oceans. Special attention is given to the widespread decline in coral reefs' health, disruptive global carbon cycles, and the many commercially valuable fish species' range shifts towards the poles. Areas of low adaptive capacity and high exposure are highlighted for urgent conservation intervention. This study demonstrates the importance of Earth and Planetary Science in temporal and spatial modeling of ecological change. Based on the results, policies and actions that aim to sustain the culture and supporting services marine ecosystems provide should focus more on climate change impacts. To put it in other words, this research aims to guide the management policies of marine resources, considering the marine ecosystems' services for the environment and human health.

Sea surface temperature (SST) variability in the shelf‐slope region of the northwest Atlantic is described and then explained in terms of latent and sensible heat exchange with the atmosphere. The basic data are primarily engine‐intake temperature measurements made by merchant ships over the period 1946–80. The data have been grouped by month and area and an empirical orthogonal function analysis has been performed to determine the dominant modes of variation. The first two modes account for 44% of the total variance. The first mode corresponds to in‐phase changes of SST from the Grand Banks to Mid‐Atlantic Bight; the second mode corresponds to opposite changes of SST on the Grand Banks and Mid‐Atlantic Bight. The time‐dependent amplitudes of these large‐scale modes have pronounced low‐frequency components; the associated changes in SST are typically 3°C. It is also shown that winter anomalies last longer than summer anomalies; their typical decay scales are 6 and 3 months, respectively. The onshore component of geostrophic wind is significantly correlated with the amplitude of the first mode in winter. We note the strong land‐sea contrast of temperature and humidity in this region during winter and explain the wind‐SST correlation in terms of latent and sensible heat exchanges. The second mode (i.e. the difference in SST between the Grand Banks and Mid‐Atlantic Bight) also appears to be related to changes in atmospheric circulation during the winter. A stochastic model for mixed layer temperature is finally used to model the SST autocorrelation functions. Following Ruiz de Elvira and Lemke (1982), it includes a seasonally‐varying feedback coefficient. The model successfully reproduces the extended persistence of winter anomalies with physically realistic parameter values but it cannot account for the summer reinforcement of winter anomalies on the Scotian Shelf. We speculate that this is due to the occasional entrainment of water, cooled the previous winter, into the shallow summer mixed layer.

Variations of the sea surface temperature (SST) and primary productivity in the northeast Pacific have far‐reaching implications. In addition to influencing the regional and global temperature and hydroclimate, these conditions also control marine ecosystems and their services, which subsequently impact regional economies. Yet, our understanding of the variability and controls of northeast Pacific SST and productivity on timescales exceeding observational records remains limited. Here, we use marine sediment records from seven locations, spanning 25.2°N–59.6°N, in the northeast Pacific to characterize the millennial‐scale variability of SST and productivity from 9,000 to 1,000 years BP. We explore the dynamics of their spatiotemporal evolution and compare these data with transient climate model outputs to identify potential drivers. Through a heat budget analysis and optimal fingerprinting analysis, we characterize the spatial pattern of forcings. We find that SST varied spatially in the northeast Pacific, with higher latitudes exhibiting greater magnitude changes than lower latitudes, which differs from previous work suggesting regional synchronicity and coherence during the Holocene. Our analysis did not find evidence for coherent variability of primary producer community nor carbon export, highlighting the difficulty of identifying the complex interactions between environmental conditions, producers, and carbon export. Model‐proxy disagreement demonstrates the need for higher resolution model frameworks, but shows nonetheless that observed variability in the proxy records can be explained by a combination of greenhouse gas and orbital forcing. We suggest that the complex SST variations and marine ecosystem responses to forced changes are important factors that can drive disagreements in model projections.

Changes over the scale of decades in oceanic environments present a range of challenges for management and utilisation of ocean resources. Here we investigate sources of global temporal variation in Sea Surface Temperature (SST) and Ocean Colour (Chl-a) and their co-variation, over a 14 year period using statistical methodologies that partition sources of variation into inter-annual and annual components and explicitly account for daily auto-correlation. The variation in SST shows bands of increasing variability with increasing latitude, while the analysis of annual variability in Chl-a shows mostly mid-latitude high variability bands. Covariation patterns of SST and Chl-a suggests several different mechanisms impacting Chl-a change and variance. Our high spatial resolution analysis indicates these are likely to be operating at relatively small spatial scales. There are large regions showing warming and rising of Chl-a, contrasting with regions that show warming and decreasing Chl-a. The covariation pattern in annual variation in SST and Chl-a reveals broad latitudinal bands. On smaller scales there are significant regional anomalies where upwellings are known to occur. Over decadal time scales both trend and variation in SST, Chl-a and their covariance is highly spatially heterogeneous, indicating that monitoring and resource management must be regionally appropriate.

Changes in tropical sea surface temperature (SST) are examined over the period 1950–2011 during which global average temperature warmed by 0.4°C. Average tropical SST is warming about 70% of the global average rate. Spatially, significant warming between the two time periods, 1950–1980 and 1981–2011, has occurred across 65% of the tropical oceans. Coral reef ecosystems occupy 10% of the tropical oceans, typically in regions of warmer (+1.8°C) and less variable SST (80% of months within 3.3°C range) compared to non‐reef areas (80% of months within 7.0°C range). SST is a primary controlling factor of coral reef distribution and coral reef organisms have already shown their sensitivity to the relatively small amount of warming observed so far through, for example, more frequent coral bleaching events and outbreaks of coral disease. Experimental evidence is also emerging of possible thermal thresholds in the range 30°C–32°C for some physiological processes of coral reef organisms. Relatively small changes in SST have already resulted in quite large differences in SST distribution with a maximum ‘hot spot’ of change in the near‐equatorial Indo‐Pacific which encompasses both the Indo‐Pacific warm pools and the center of coral reef biodiversity. Identification of this hot spot of SST change is not new but this study highlights its significance with respect to tropical coral reef ecosystems. Given the modest amount of warming to date, changes in SST distribution are of particular concern for coral reefs given additional local anthropogenic stresses on many reefs and ongoing ocean acidification likely to increasingly compromise coral reef processes.

The spatial structure of El Nino–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM), which are the two most important climate modes affecting sea surface temperature (SST) variability in the Southern Hemisphere (SH), appear to have changed since 1999. The characteristic features of the ENSO- and SAM-related atmospheric and oceanic variability in the SH are compared between two sub-periods (1979–1998 and 1999–2012) using cyclostationary empirical orthogonal function analysis. During the earlier period of 1979–1998, the ENSO is characterized by conventional eastern Pacific type, in which the signals in the SH constitute the Pacific South America teleconnection pattern. In contrast, due to a shift of the active center of ENSO to the central Pacific in the later period (1999–2012), atmospheric circulation and SST variability over the SH significantly vary. Moreover, the SAM-related SST variability also shows remarkable differences before and after 1998–1999. This difference is primarily attributed to differences in the non-annular spatial component of the SAM between the two periods. Due to the changes in the spatial structure of the SAM, as well as those of the ENSO, SST variability in the SH displays a marked change between the two periods. Detailed descriptions of the decadal changes of the SH SST in terms of interaction in the oceanic and atmospheric variability are presented along with the possible implications of this change.

South America’s large marine ecosystems (LMEs) span extensive oceanic regions, encompassing coastal areas such as river basins (e.g., the Amazon) and estuaries (e.g., La Plata), as well as the outer boundaries of continental shelves, including the Patagonian east coast. These LMEs also include major coastal current systems like the Humboldt Current (HC). The five key LMEs in the region—the Humboldt, Patagonia, and the North, East, and South Brazil Shelf LMEs—exhibit substantial variability across multiple timescales due to diverse environmental factors. In marine ecosystems, the availability of light, carbon dioxide (CO₂), and nutrients is essential for sustaining primary production, while oxygen is crucial for supporting higher trophic levels. A key driver of marine productivity is upwelling, a process where favorable winds bring nutrient-rich deep waters to the surface. Currents and frontal zone, together with mixing and eddies, are important sources for nutrients. Additionally, terrestrial riverine runoff from basins, such as the Amazon, serves as a vital nutrient source, further enhancing marine productivity. These ecosystems are highly sensitive to changes in sea-level pressure, temperature, wind patterns, rainfall, and ocean currents, which are influenced by larger climatic variability patterns operating at various temporal scales. Notable among these are the El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM), at interannual timescales and the Pacific Decadal Oscillation (PDO) at decadal timescales. Furthermore, the pervasive effects of global warming pose significant threats to marine ecosystems, disrupting the complex interdependencies within them. At interannual timescales, ENSO represents the primary mode of climate variability. During its positive phase (El Niño), ENSO induces significant warming of the tropical Pacific surface waters, weakening seasonal winds off the coasts of Peru and Chile. This disruption reduces coastal upwelling, leading to a decline in nutrient availability in the euphotic zone and, consequently, a decrease in primary production in the region. Additionally, variations in sea surface temperature (SSTs) in the tropical Pacific alter atmospheric circulation patterns, including Walker cells, reducing precipitation over the Amazon basin. This diminished rainfall leads to lower nutrient discharge at river mouths, further limiting nutrient inputs critical for primary production. ENSO is linked to the South Atlantic Subtropical Dipole, which influences density gradients across the Malvinas Front, thereby affecting productivity over the Brazilian and Argentine shelves. Additionally, the positive phase of ENSO, along with the positive mode of the Tropical North Atlantic (TNA), has been associated with marine heat waves, leading to disturbances in marine ecosystems, particularly in northern Brazil. The Atlantic Niño mode, which peaks during the summer, similarly impacts regional ecosystems. In its positive phase, it elevates equatorial Atlantic SSTs, diminishing productivity there. The SAM is another interannual mode playing a significant role by altering the behavior of subtropical anticyclones, which in turn modulates upwelling processes critical for marine ecosystem dynamics. Regarding decadal variability, decadal biological regime shifts in the HC system reflect fluctuations in sardine (Sardinops sagax) and anchovy (Engraulis ringens), key species in this “wasp-waist” ecosystem. Anchovy dominance aligns with cooler periods (1950–1970, 1985–present), while warmer intervals (1970–1985) favor sardines. These shifts restructure energy transfer from plankton to predators. Similar patterns in systems like the California and Benguela Currents suggest large-scale drivers, including the PDO and North Pacific Gyre Oscillation; the latter may explain ecosystem-wide synchrony. The effects of these climate variability modes on LMEs have significant socioeconomic implications, particularly for fisheries-dependent communities in the region. Fluctuations in marine productivity driven by climatic patterns directly impact fish stocks, jeopardizing livelihoods and regional economies. It is crucial to recognize the complex interactions between climatic variability and marine ecosystems, as they highlight the interconnectedness of environmental and human systems and the far-reaching consequences of these changes.