Sea Surface Temperature rise (SST) refers to the significant increase in the temperature of ocean surface waters, primarily driven by anthropogenic climate change. This trend has profound implications for the global climate system. For example, the average sea surface temperature (SST) over the extrapolar ocean has increased by about 0.6°C over the last four decades and about 0.9°C since the pre-industrial era., influencing cyclone formation and intensity.

The Phenomenon of Sea Surface Temperature Rise:

• Greenhouse Gas Emissions and Ocean Heat Absorption: Increased greenhouse gas concentrations trap heat in the atmosphere, causing oceans to absorb more heat. This absorption results in a rise in sea surface temperatures (SST), contributing to global warming and altering marine ecosystems.
• Carbon Dioxide Absorption: Oceans act as carbon sinks, absorbing about 30% of human-emitted CO₂. As CO₂ dissolves in water, it reacts to form carbonic acid, altering ocean chemistry and contributing to the warming of surface waters.
• Albedo Effect: The melting of polar ice reduces the Earth’s reflective surface (albedo), allowing more sunlight to be absorbed by ocean waters. This accelerates SST rise, leading to further ice melt in a feedback loop, which worsens sea level rise and disrupts polar ecosystems.
• Global atmospheric temperature rise: According to NASA’s Goddard Institute for Space Studies (GISS), global sea surface temperatures (SST) have risen in parallel with global atmospheric temperatures, increasing by approximately 1°C since 1880.
• Altered Ocean Currents: Changes in ocean currents, like the slowdown of the Atlantic Meridional Overturning Circulation (AMOC), disrupt heat distribution and lead to localized warming.
• Increased Solar Radiation: Enhanced greenhouse gas concentrations trap more heat in the atmosphere, causing oceans to absorb more solar energy and increase surface temperatures.
  For example: The Mediterranean Sea has warmed by approximately 4°C per decade from 1985 to 2006, altering marine ecosystems and weather patterns in surrounding regions.

Impact of SST Rise on Tropical Cyclone Formation:

• Increased Intensity: Higher SST provides more energy to developing tropical cyclones, intensifying their strength.
  For example: Cyclone Amphan (2020), which struck India and Bangladesh, was fueled by abnormally warm Bay of Bengal waters, reaching super-cyclone status.
• More Frequent and Severe Storms: Rising SSTs lead to an increase in the number of severe tropical cyclones.

For example: The 2020 Atlantic hurricane season, which was one of the most active on record, saw 30 named storms, driven in part by higher-than-average SSTs in the Atlantic.

• Amplified Rainfall: Warmer ocean surfaces increase the moisture content in the atmosphere, leading to heavier rainfall during cyclones. This can cause devastating floods.
• Extended Duration: Cyclones fueled by higher SSTs tend to last longer and travel further inland. For example: Cyclone Idai (2019), maintained its intensity well after landfall in Mozambique due to the unusually warm waters of the Mozambique Channel.
• Shifts in Cyclone Tracks: SST rise can alter cyclone tracks, pushing them toward regions that historically experienced fewer such storms.

For instance: Hurricane Ophelia (2017) reached as far as Ireland, a rare occurrence attributed to anomalous SSTs in the North Atlantic.

• Impact on Vulnerable Regions: Countries with warmer waters, such as those bordering the Indian and Pacific Oceans, are more prone to intensified tropical cyclones.
  For example: The Philippines and the Caribbean already have frequent targets of typhoons and hurricanes, and face increased risks due to the warming ocean temperatures.

The rise in sea surface temperatures significantly challenges us by increasing the intensity and frequency of tropical cyclones. However, global climate action, including reducing greenhouse gas emissions and adopting sustainable coastal development practices, can help mitigate this rise. Furthermore, advancements in cyclone forecasting and coordinated international efforts are crucial for enhancing resilience and safeguarding ecosystems and communities.

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