Sea Surface Temperature (SST) Rise refers to the increase in the temperature of the ocean’s upper layer, typically the top 100 meters. It is primarily driven by global warming and is influenced by factors such as increased greenhouse gas emissions, which trap more heat in the Earth’s atmosphere, and the absorption of this heat by the oceans. Since oceans cover about 71% of Earth’s surface, they play a crucial role in regulating global temperatures.
Effects of Sea Surface Temperature Rise on the Formation of Tropical Cyclones:
Tropical cyclones (also called hurricanes, typhoons, or cyclones, depending on the region) are large, rotating storm systems that form over warm ocean waters near the equator. Sea surface temperature plays a critical role in their formation and intensity. Here’s how SST rise affects tropical cyclones:
1. Increased Cyclone Formation:
- Warm waters (generally above 26.5°C or 80°F) are necessary for the formation of tropical cyclones. Warmer SSTs provide more energy for the storm system. As ocean temperatures rise due to global warming, it increases the likelihood of tropical cyclones forming, especially in areas that previously did not meet the temperature threshold.
- Latitudinal Shift: Rising SSTs can also cause a shift in cyclone formation zones toward higher latitudes (closer to the poles), as warmer waters are now extending farther from the equator. This could expose new areas to cyclone risk.
2. Increased Cyclone Intensity:
- More heat energy from the warmer ocean waters leads to the evaporation of more water, which fuels the cyclone’s energy. The additional moisture in the atmosphere strengthens the storm system.
- More intense storms: Higher SSTs provide cyclones with more latent heat, leading to a greater likelihood of stronger winds, more powerful storm surges, and heavier rainfall. Many studies indicate that rising SSTs are contributing to the increasing intensity of tropical cyclones, making Category 4 and Category 5 storms more frequent.
3. Increased Rainfall:
- Warmer SSTs enhance evaporation rates and result in more moisture being available in the atmosphere. This translates into heavier precipitation during cyclones, leading to more intense rainfall and an increased risk of flooding in affected regions.
4. Slower Storm Movement:
- There is some evidence suggesting that slower storm movement may be linked to rising SSTs. This means that cyclones may linger longer over coastal areas, dumping more rain and causing more prolonged flooding and wind damage.
5. Storm Surges:
- Rising SSTs contribute to more intense storm surges due to stronger cyclones and rising sea levels (caused by thermal expansion of the ocean). Storm surges result in coastal flooding, which can be catastrophic, especially in densely populated or low-lying coastal areas.
6. More Frequent Intense Cyclones:
- While the overall frequency of tropical cyclones may not increase significantly, the proportion of stronger, more destructive cyclones (Category 4 and 5) is expected to rise due to warmer ocean temperatures. These storms can lead to more severe human and environmental impacts, including economic damage, loss of life, and habitat destruction.
7. Impacts on Cyclone Tracks:
- Changes in SST patterns and global climate systems can alter the paths that cyclones follow. This could lead to shifts in cyclone impact zones, affecting regions that have not traditionally experienced severe storms or where infrastructure is not prepared to withstand tropical cyclones.
Conclusion:
The rise in sea surface temperatures has a profound impact on the formation, intensity, and behavior of tropical cyclones. Warmer oceans provide the necessary energy to fuel more intense and longer-lasting storms, increase the likelihood of catastrophic rainfall, and lead to higher storm surges. With climate change causing a steady rise in SSTs, the risk of stronger and more destructive tropical cyclones is growing, posing serious challenges to coastal communities, economies, and ecosystems.
