Marine Heat Wave

Oct. 20, 2024

Researchers found that marine heat waves (MHWs) deep in oceans may be “significantly under-reported” and caused by ocean currents.

About Marine Heat Wave:

  • A marine heat wave is an extreme weather event
  • It occurs when the surface temperature of a particular region of the sea rises to 3 or 4 degree Celsius above the average temperature for at least five days. 
  • MHWs can last for weeks, months or even years, according to the US government’s agency National Oceanic and Atmospheric Administration (NOAA).
  • Impacts
    • MHWs are prolonged temperature events that can cause severe damage to marine habitats, such as impacts to coral reefs and species displacement.
    • These events are becoming more frequent due to global warming, with notable occurrences off Australia's East Coast and Tasmania, as well as the northeast Pacific coast and North Atlantic.
    • Higher ocean temperatures, which are associated with MHWs, can make storms like hurricanes and tropical cyclones stronger.
    • MHWs also fuel the growth of invasive alien species, which can be destructive to marine food webs. 
    • When storms travel across hot oceans, they gather more water vapour and heat.
    • This results in more powerful winds, heavier rainfall and more flooding when storms reach the land — meaning heightened devastation for humans.