SOCIB confirms the ocean warming persistence in the Mediterranean Sea in response to climate change through record trends observed over the period 1982-2021

  • SOCIB has developed applications that provide valuable information on ocean temperature and sea level variations in the Mediterranean Sea over the last 40 years, indicating record trends updated through the last year (2021).

  • Processing, analysis and automatic visualization of satellite data in different sub-regions of the Mediterranean Sea at various temporal scales are performed through these applications, designed by Dr. Mélanie Juza, researcher at SOCIB.

The systematic and long-term ocean monitoring, enabled by satellite observations for sea surface temperature and sea level among other ocean variables, allows estimating the ocean surface variations over the last decades. As an Observatory of the Mediterranean Sea, the Balearic Islands Coastal Observing and Forecasting System (SOCIB) has developed free and open access visualization tools for the Mediterranean Sea to provide continuous and timely updated information on the ocean state and variability in the different sub-regions at various temporal scales. These applications have been enabled by the Copernicus Marine Service which provides full, free and open access to quality-controlled historical and near real-time data.

Specifically, the applications Sub-regional Mediterranean Sea indicators and Sub-regional Mediterranean marine heat waves are valuable web-based visualization tools that provide ocean information through maps and figures. These user-friendly portals have been designed to be consulted by diverse stakeholders, including the scientific community, educators in marine science, environmental agencies and policy decision-makers.

As a semi-enclosed and relatively small basin with many coastal areas, the Mediterranean Sea is one of the most vulnerable regions to climate change and responds rapidly to global warming. The surface Mediterranean warming rate is approximately three or four times higher than the global ocean and has dramatically increased over the last decades. Global warming-related consequences worsen the severe pressure from human activity in the Mediterranean (e.g., overfishing, contamination, maritime trade or coastal development) and threaten the Mediterranean Sea. The warm temperatures and the increasing frequency and intensity of extreme events (e.g., storms and marine heat waves) are affecting all the ocean layers and marine ecosystems. Such changes will severely impact the provision of ecological goods and services in the coming decades, affecting the key sectors of the blue economy.

The monitoring and visualization tools developed at SOCIB have enabled us to automatically update through 2021 the long-term variations in the Mediterranean in response to global warming. More precisely, the linear trends of sea surface temperature (SST) have been recently observed over the period 1982-2021 with values ranging from 0.2 to 0.64ºC/decade (Figure 1).

Figure 1. Linear trend of SST (ºC/year) from CMEMS satellite products over 1982-2021Link

 

This rapid increase of SST is associated with an increasing number of extreme events, in particular marine heat waves (MHW). MHWs occur when ocean temperatures are much warmer than normal during a prolonged period. The trend values of annual MHW total days have been also estimated over the period 1982-2021 oscillating from 7 to 45 days/decade (Figure 2). 

Figure 2. Linear trend over 1982-2021 of annual MHW total days, which are computed using CMEMS SST satellite products. Link

 

Climate change also contributes to sea level variations, through the increase of ocean volume caused by thermal expansion of ocean water and the increase of ocean water mass caused by land ice melting. The recent trends obtained from sea level anomaly (SLA) time series over the period 1993-2021 reach values up to 57 cm/decade (Figure 3).

Figure 3. Linear trend of SLA (cm/year) from CMEMS satellite products over 1993-2021. Link

 

Besides the slow variations of the ocean surface, these interactive tools also provide daily monitoring that allows the detection of remarkable events in real time (such as marine heat waves, extreme river discharge, mesoscale eddy and deep convection among others oceanic phenomena that directly impact the ocean circulation and marine ecosystem). Such applications contribute to increasing the transfer of knowledge for sustainable management and the protection of the ocean.

Reference articles

  • Juza, M. and Tintoré, J. (2021). Multivariate sub-regional ocean indicators in the Mediterranean Sea: from event detection to climate change estimations, Frontiers in Marine Science, 8:610589, https://doi.org/10.3389/fmars.2021.610589

  • Juza, M., Fernández-Mora, A., and Tintoré, J. (2022). Sub-regional marine heat waves in the Mediterranean Sea from observations: long-term surface changes, sub-surface and coastal responses, Frontiers in Marine Science, 785771, https://doi.org/10.3389/fmars.2022.785771