Syllabus
GS Paper 1 – Geographical features and their location-changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.
Context
According to a study by the Indian Institute of Tropical Meteorology (IITM), marine heatwaves, which are associated with the swift development of cyclones, are projected to rise tenfold. This means an increase from the present average of 20 days per year to an estimated 220–250 days per year.
Marine Heatwaves
Introduction
A team of researchers from the Indian Institute of Tropical Meteorology in Pune, along with international collaborators, recently conducted a study forecasting the potential impact of global carbon emission trends on the Indian Ocean. The study reveals that the Indian Ocean has already experienced a temperature rise of 1.2°C and predicts a further increase of 1.7° C-3.8° C between 2020 and 2100. This warming trend could have significant implications for marine ecosystems and weather patterns in the region, underscoring the urgent need for effective climate change mitigation strategies.
Marine Heat Waves
- Marine heat waves are extended durations of abnormally high sea temperatures in a specific area.
- These phenomena are typically triggered by a mix of natural climate fluctuations and human-induced climate change.
- During these heat waves, ocean temperatures can soar several degrees above the norm for prolonged periods, sometimes spanning weeks to months.
- A notable instance of a marine heat wave is “The Blob,” which took place in the North Pacific Ocean from 2013 to 2016. This extraordinary warm water mass had extensive effects on marine ecosystems, impacting a wide range of organisms from plankton to marine mammals and seabirds.
Causes of Marine Heatwaves
- Atmospheric Influence: Changes in atmospheric circulation patterns can affect ocean temperatures. For instance, high-pressure ridges in the atmosphere can lead to increased solar radiation, resulting in warmer ocean surface temperatures.
- Role of Ocean Currents: Fluctuations in ocean currents can transport warmer water to regions where it’s not usually present, causing localized ocean temperature increases. Changes in ocean circulation patterns, like El Niño events, can also contribute to marine heat waves.
- Impact of Climate Change: Human-induced climate change is a major contributor to marine heat waves. The global warming caused by increased greenhouse gas emissions can raise ocean temperatures worldwide, intensifying the frequency and severity of marine heat wave events.
- Natural Climate Variability: Natural climate variability, such as the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO), can influence ocean temperatures over longer time scales. Shifts in these climate patterns can lead to periods of unusually warm ocean temperatures, contributing to marine heat waves.
- Local Factors: Local factors like coastal geography, upwelling patterns, and freshwater input from rivers can also influence the development of marine heat waves. For example, coastal areas with shallow waters or limited exchange with the open ocean may be more susceptible to temperature extremes.
Impact of Marine Heatwaves
- Extreme Weather Events: ‘Marine heatwaves’, which are linked to the swift formation of cyclones, are projected to increase tenfold from the current average of 20 days per year to 220–250 days per year.
- Impact on Mainland India: The warming of the Indian Ocean has significant repercussions for mainland India, with an increase in severe cyclones and erratic monsoon patterns, leading to prolonged droughts followed by intense rainfall and flooding.
- Coral Bleaching: High ocean temperatures can stress coral reefs, causing coral bleaching where corals expel the algae living in their tissues, turning them white. This makes the corals more prone to disease and death, leading to long-term damage to coral reef ecosystems.
- Changes in Species Distribution: Marine heatwaves can cause shifts in the distribution and abundance of marine species as they seek out suitable temperatures. This can disrupt ecosystems and alter predator-prey relationships, leading to cascading effects throughout the food web.
- Fisheries Disruption: Marine heatwaves can affect fish populations by altering their behavior, reproductive patterns, and habitat availability. This can impact commercial and recreational fisheries, leading to reduced catches and economic losses for fishing communities.
- Loss of Biodiversity: The stress caused by marine heatwaves can lead to mass mortality events for marine organisms such as fish, invertebrates, and marine mammals. This can result in the loss of biodiversity and alter the structure and functioning of marine ecosystems.
- Harmful Algal Blooms: Warm ocean temperatures can promote the growth of harmful algal blooms (HABs), which produce toxins that can harm marine life and pose risks to human health through the consumption of contaminated seafood and exposure to toxins in the water.
- Impact on Ecosystem Services: Marine ecosystems provide valuable ecosystem services such as coastal protection, carbon sequestration, and nutrient cycling. Marine heatwaves can disrupt these services, leading to negative impacts on coastal communities and economies.
- Social and Economic Impacts: Coastal communities that depend on marine resources for food, livelihoods, and recreation can be severely impacted by marine heatwaves. Economic losses can occur due to declines in fisheries, tourism, and related industries, as well as damage to infrastructure and coastal property.
Way forward
- Global Commitments and Ocean Response: Current global efforts to curb greenhouse gas emissions are unlikely to significantly impact the state of the oceans. Unlike on land, the seas respond more slowly to changes in external inputs.
- Understanding the Indian Ocean’s Impact: A practical solution is to refine our understanding of the local impact of the Indian Ocean.
- Collaborative Efforts for Data Gathering: India needs to establish a cooperative relationship with countries bordering the Indian Ocean to invest in data collection. Currently, this is significantly less than what is available for the Pacific, for example.
- Guiding Development and Protection: The collected data and projections can be used to guide the development and protection of infrastructure and people.
Conclusion
Marine Heatwaves (MHWs) are increasingly frequent and severe, with a significant rise in the last year. This is primarily due to global warming, but natural drivers like El Niño also contribute. MHWs have disastrous impacts on marine life2 and are no longer considered extreme events. The frequency and regions under the influence of MHWs are increasing, necessitating improved ocean monitoring and weather model updates. Understanding MHWs can help gauge the severity of climate change impacts and devise mitigation strategies.
Reference: The Hindu
Related PYQ
Discuss the meaning of colour-coded weather warnings for cyclone prone areas given by India Meteorological Department. [UPSC Civil Services Exam – 2022 Prelims]
Practice Question
“Marine heatwaves have been recognized as a critical environmental issue with extensive implications for marine ecosystems and coastal communities. Elucidate on the causes of marine heatwaves and discuss their impacts.” [150 words]
How to approach this question?
Introduction (20 words): Start by defining marine heatwaves and their significance. Briefly mention their impact on marine ecosystems and coastal communities.
Body (100 words):
- Causes of Marine Heatwaves (50 words): Discuss the various causes of marine heatwaves such as ocean currents, air-sea heat flux, winds, and climate phenomena like El Niño. Use examples if possible.
- Impacts of Marine Heatwaves (50 words): Discuss the impacts of marine heatwaves on marine life, extreme weather events, socio-economic impacts, and biodiversity. Provide specific examples to illustrate these impacts.
Conclusion (30 words): Conclude by emphasizing the need for research, better prediction and warning systems, and regional measures to build ocean resilience to mitigate these impacts.
Remember to provide a balanced answer, incorporating relevant facts and figures, and propose feasible solutions. Structure your answer well, with a clear introduction, body, and conclusion. Also, ensure that your answer is within the word limit specified for the exam. Good luck!