Syllabus

GS 3: Environment

Context: - 

The Mediterranean Sea is experiencing most extreme marine heatwave ever recorded for the time of year. Scientists say it could be once in a blue moon event.

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• This means some areas of the sea is 8°C (+14F) warmer than normal time of the year. Such high temperatures would not happen without global warming. 
• During this heat wave the temperature of the surface and sub-surface of the sea are much higher than normal for extended period of time. 
• The worst-affected parts of the western Mediterranean Sea are central region, Balearic Sea and the Tyrrhenian Sea. 

What is Marine Heat wave

• Marine heat wave (MHW) refers to an event where ocean temperature in a particular region remains abnormally high for an extended period of time. 
• They can occur any ocean or sea lasting days to months and cover hundreds to thousands kilometres.
• The overall deviation of sea surface temperatures in the Mediterranean is six standard deviations from the normal for this time of the year.
• The major cause is global warming and heat dome– when area of high pressure traps hot air over a region warm air is pushed upwards by high pressure which keep heat from escaping.

Impact of Marine Heat waves 

• Rising temperature affects marine biodiversity.
• Mass bleaching of coral reefs.
• Death of sea grass meadows and kelp forest.
• Negative impact on fisheries and food security.

How Heat waves Affect Weather Patterns

• Warmer sea increases atmospheric moisture so the dew point increase and it act as a fuel for cyclones.
• It can divert jet streams and it leads to prolong dry or extreme rainfall events.
• Because of heavy rainfall, situations like floods and landslides arise.
• In urban areas, heat waves intensify the heat island effect.
• In 2024 flash floods & landslides occurred in central Bosnia. These deadly disasters unfold triggered by Warming of seas. 

About Mediterranean Sea

• Almost entirely enclosed by Southern Europe, Western Asia, and Northern Africa.
• It connected to the Atlantic Ocean via the Strait of Gibraltar, Black Sea via the Bosporus Strait and to the Red Sea via the Suez Canal.
• Semi-enclosed sea with high salinity due to evaporation exceeding precipitation and river inflow. Divided into Western and Eastern Mediterranean basins.

Source:

https://www.downtoearth.org.in/climate-change/once-in-a-billion-event-intense-marine-heatwave-in-mediterranean-shocks-with-8c-warming#:~:text=Once%2Din%2Da%2Dbillion,with%208%C2%B0C%20warming&text=The%20Mediterranean%20Sea%20is%20undergoing,%2Da%2Dbillion%20climatological%20event.