Context
According to a recent forecast of
Mercator Ocean International,
Marine Heat Waves have gripped the oceans of
north-east Pacific, the southern hemisphere in the
southern Indian Ocean and the Pacific, the north-east Atlantic, tropical North Atlantic, and the Mediterranean Sea.
About the forecast:
| Researchers are making predictions that the occurrence of Marine Heat Waves will increase as much as 50-fold by 2100 as compared to the pre-industrial times. |
What are marine heat waves?
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.
What are the impacts of marine heat waves on ocean life?
Catastrophic for marine life: Marine Heat waves may cause the deaths of several marine species, alter their
migration patterns, and lead to coral bleaching and even impact weather patterns. Although an increase of
3 or 4 degrees Celsius in average temperatures may not be much for humans, it can be catastrophic for marine life.
Destroying kelp forest: MHWs destroy
kelp forests and fundamentally altered the
ecosystem of the coast.
Enhances Coral Bleaching: A 2010 study showed that more than
80 per cent of surveyed corals had bleached and over 40 per cent of the total surveyed had died.
Corals are very sensitive to the temperature of the water in which they live.
Disturbs food web: MHWs also fuel the growth of
invasive alien species, which can be destructive to marine food webs.
How do marine heat waves affect humans?
Increasing the intensity of storms: Higher Ocean temperatures, which are associated with MHWs, can make storms like
hurricanes and tropical cyclones stronger.
Increased evaporation and heat: With warmer temperatures, the
rate of evaporation escalates and so does the transfer of heat from the oceans to the air.
More devastating effects: 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.
Factors contributing to Marine Heat Waves:
Global Warming: Rise in temperatures due to Anthropogenic events, has led to an increase in global temperatures which ultimately contributes to ocean warming.
El Nino: Winds can enhance or suppress the warming in a marine heatwave, and climate models like El Niño can change the likelihood of events occurring in certain regions.
Ocean currents: The most common drivers of marine heatwaves include ocean currents which can build up areas of warm water and air-sea heat flux, or warming through the ocean surface from the atmosphere.