28 May 2019 - While the impacts of climate change are reflected in storms, heat waves, floods and droughts that ravage communities around the world, the ocean too is feeling the heat.
Marine heatwaves, defined as periods of above-average temperatures, are causing a range of effects, including species migrations and invasions, disruptions or closures to fisheries, and stress and death in aquaculture stocks.
"Marine heatwaves have become longer and more frequent over the last century," says Dr. Eric Oliver, Professor, Dalhousie University's Department of Oceanography, with research showing that annual marine heatwave days have increased by 54 per cent from 1925 to 2016, accelerating since 1982.
"Marine ecosystems that once experienced 30 days of extreme heat per year in the early 20th century now experience 45 marine heatwave days per year. Exposure to extreme heat is creating detrimental effects on ecosystem health, with impacts on biodiversity as well as economic activities including fisheries and aquaculture," says Dr. Oliver. "We're at a critical stage — a metaphorical boiling point — for the ocean."
To better understand the impacts to the ocean, Dr. Oliver co-organizes an international working group to observe marine heatwaves through an interactive website, www.marineheatwaves.org/tracker. The website allows users to click on any location in the global ocean and see the history of marine heatwaves from current day back to 1982.
Dr. Robert Schlegel, Postdoctoral Fellow with the Ocean Frontier Institute, says the benefits of the tool are significant.
"Anyone can now have, at their fingertips, the past and present state of marine heatwaves around the globe. This provides critically important information not just to climate researchers, but also to those whose livelihoods and communities are impacted by the sea."
For example, the website shows that a severe marine heatwave occurred off the Mediterranean coast of Spain from January to March 2019 — information not available through mainstream media. It also indicates that a marine heatwave nicknamed "The Blob" that occurred along the Pacific coast of Canada from 2014 to 2016 is making a comeback.
"The marine heatwave tracker provides important data free to all and advances our collective understanding of how climate change is impacting different regions of the ocean," says Dr. Schlegel.