The Canary Islands have been facing the impact of a marine heatwave since March, which is characterized by a notably rapid increase in ocean surface temperatures. This increase has been unprecedented since the commencement of in situ measurements in 1982, and it has led to a rise of half a degree Celsius in just one year.
Pedro Vélez Belchí, the director of the Oceanographic Centre of the Canary Islands, underscores the remarkable nature of this event compared to the historical records of the last four decades. Unlike previous instances of gradual temperature increases, this year has witnessed a substantial and abrupt surge in sea temperatures. Remarkably, the highest sea temperature of the year occurred in mid-October, which deviates from the typical pattern of this peak happening at the end of August or the beginning of September.
The exact causes behind this heatwave are still subject to investigation and debate among experts. Multiple hypotheses are being explored, including the influence of global warming, the El Niño phenomenon observed since February, and the potential impact of the Hunga Tonga supereruption in the Pacific in January 2022. This volcanic eruption released a significant amount of water vapor into the stratosphere, and there are theories suggesting its potential influence on climate for several years.
The United Nations emphasizes the critical role of oceans as carbon sinks, responsible for absorbing excess heat and energy resulting from greenhouse gas emissions. The consequences of rising ocean temperatures include the melting of polar ice, sea-level rise, occurrences of marine heatwaves like the current one, and ocean acidification.
Impact on the Canary Islands
Regarding the specific impact on the Canary Islands, Pedro Vélez points to potential shifts in the spawning times of marine organisms and a reduction in resources for small pelagic species due to decreased primary production caused by warmer waters. While sea-level rise in the region has been relatively gradual, Vélez highlights the importance of studying acceleration trends rather than just continuous increases in sea levels to assess the impact of global warming accurately.
Despite the ongoing warming trend observed in the upper layers of the ocean, studies conducted by the Oceanographic Centre reveal relatively stable temperatures at depths of up to 800 meters since 1997, with exceptions during the 2015 El Niño event. No significant alterations have been observed up to depths of 1,500 meters, and in the deepest parts where precise measurements are taken, a slight cooling has been detected.
The Oceanographic Centre of the Canary Islands plays a pivotal role in researching the marine ecosystem across various levels, from studying bacteria to monitoring cetacean populations. While the center employs 70 individuals, including 13 researchers, its director emphasizes the need for additional resources to continue their essential work in understanding and addressing the effects of climate change on the oceans and marine life.