MARINE HEATWAVE

• Coral Bleaching: Marine heat waves can lead to coral bleaching, a phenomenon in which corals expel symbiotic algae, causing them to lose their vibrant colors and become more susceptible to disease. If the heat stress is severe and prolonged, it can result in coral mortality, leading to the degradation of coral reefs, which are vital marine ecosystems supporting diverse marine life.
• Disruption of Marine Food Chains: Elevated sea surface temperatures can disrupt the timing and availability of plankton blooms, affecting the entire marine food chain. Many marine species rely on specific temperatures for breeding and feeding, and changes in SSTs can alter the distribution and abundance of various marine organisms.
• Migration and Distribution: Marine heat waves can cause shifts in the distribution and migration patterns of marine species. Some species may move to cooler waters or deeper depths in search of suitable temperatures, affecting predator-prey relationships and altering ecosystem dynamics.
• Impact on Marine Mammals: Marine heat waves can lead to changes in the distribution and availability of prey for marine mammals, such as whales and dolphins. These animals may be forced to travel greater distances in search of food, which can affect their reproductive success and overall health.
• Harmful Algal Blooms: Elevated sea temperatures can trigger the proliferation of harmful algal blooms (HABs), leading to "red tides" and other toxic blooms. These blooms can release harmful toxins that have devastating effects on marine life, including fish, shellfish, and marine mammals.
• Loss of Biodiversity: Prolonged marine heat waves can cause significant declines in biodiversity as certain species may struggle to adapt to rapidly changing conditions. This can lead to imbalances in marine ecosystems and a reduction in overall biodiversity.
• Impact on Fisheries: Marine heat waves can affect fish populations by altering their distribution, abundance, and reproduction. This can have economic implications for fisheries, affecting the livelihoods of communities dependent on fishing.
• Ocean Acidification: High sea surface temperatures can exacerbate ocean acidification, which occurs when the ocean absorbs excess carbon dioxide from the atmosphere. Acidification can harm marine organisms with calcium carbonate shells or skeletons, such as corals, mollusks, and some plankton species.

Image Source: IUCN

On human life

• Threats to Coastal Communities: As marine heat waves contribute to rising sea surface temperatures, they can intensify tropical cyclones and hurricanes, posing a greater threat to coastal communities. These extreme weather events can lead to storm surges, flooding, and property damage, putting human lives at risk and leading to displacement and economic losses.
• Effects on Human Health: Marine heat waves can promote the proliferation of harmful algal blooms (HABs), which release toxins into the water. These toxins can contaminate seafood, leading to foodborne illnesses in humans who consume affected shellfish or fish. Additionally, prolonged exposure to high temperatures and humidity during heat waves can pose health risks, particularly for vulnerable populations such as the elderly and those with pre-existing health conditions.
• Impact on Tourism and Recreation: Coastal regions often depend on tourism and recreational activities. Marine heat waves can lead to coral bleaching and degradation of marine ecosystems, reducing the appeal of coastal destinations for tourists. Additionally, extreme heat events can deter visitors and affect businesses reliant on tourism revenue.
• Water Scarcity and Quality: Marine heat waves can exacerbate water scarcity in coastal regions by accelerating evaporation and reducing freshwater availability. Additionally, extreme heat events can increase water temperatures, impacting water quality and making it more challenging to maintain safe drinking water supplies.

4. What is Global Warming?

• Global warming refers to the long-term increase in Earth's average surface temperature due to the accumulation of greenhouse gases in the atmosphere.
• The Earth's natural greenhouse effect is essential for maintaining a stable and habitable climate.
• It works by trapping some of the sun's energy in the atmosphere, keeping the planet warm enough to support life.
• However, human activities such as burning fossil fuels (coal, oil, and natural gas), deforestation, and industrial processes, have significantly increased the concentration of greenhouse gases in the atmosphere.
• The primary greenhouse gases responsible for global warming include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases.

5. How is global warming affecting marine heat waves and oceans?