Impact of Climate Change on Ocean Colour

Impact of Climate Change on Ocean Colour

This article covers “Daily Current Affairs” and the topic details “Impact of Climate Change on Ocean Colour”. The topic “Impact of Climate Change on Ocean Colour” has relevance in the Environment section of the UPSC CSE exam.

For Prelims:

Key Highlights of the Study?

For Mains:

GS 3: Environment

India’s Climate Change Mitigation Initiatives?

About MODIS?

Why in the news?

A recent study has suggested that climate change is causing the world’s oceans to turn “green,” as indicated by the analysis of ocean water. Researchers have attributed this phenomenon to anthropogenic human activities, emphasizing that it is one of the many impacts of climate change. The greening of ocean waters is particularly prominent in areas near the equator and in low latitudes.

Key Highlights of the Study:

Long-Term Trends and Data Analysis:

  • Researchers analyzed data from the Aqua satellite’s MODIS instrument, monitoring ocean color for two decades (2002-2022).
  • MODIS measures visible light in seven wavelengths, detecting subtle color changes in the oceans, which human eyes cannot perceive.
  • Green-colored water indicates the presence of phytoplankton, crucial microscopic plant-like organisms forming the base of the marine food web.
  • The color of the ocean affects carbon dioxide absorption, with oceans currently absorbing 25% of global CO2 emissions.

Role of Climate Change:

  • The study identifies climate change as the primary driver behind observed changes in ocean color over the two decades.
  • Researchers simulated scenarios considering greenhouse gas emissions, predicting significant color changes in 50% of the world’s surface oceans, in line with observed shifts to green or blue waters.

Implications for Marine Life and Conservation:

  • Changes in phytoplankton population will impact organisms dependent on them for food.
  • Different plankton types’ ability to absorb carbon influences the ocean’s capacity for carbon sequestration.

Regional Variability and the Need for Further Study:

  • The southern Indian Ocean exhibits significant color changes, while waters near India may show different trends due to natural variability.
  • Ongoing monitoring and research are essential to understand regional variations and climate change’s full impact on ocean color.
  • Turning Green: Why oceans are changing colour

India’s Climate Change Mitigation Initiatives:

National Action Plan on Climate Change (NAPCC):                                     

  • Launched in 2008 to address climate change challenges in India.
  • Comprises 8 national missions focusing on various aspects of climate change, such as renewable energy, energy efficiency, sustainable habitat, water, Himalayan ecosystem, forestry, agriculture, and strategic knowledge for climate change.

Nationally Determined Contributions (NDC):

  • India’s commitments to reduce greenhouse gas emissions and adapt to climate change.
  • Aims to reduce emissions intensity of GDP by 45% by 2030 from 2005 levels, generate 50% of electricity from non-fossil fuel sources by 2030, and achieve net-zero emissions by 2070.

National Adaptation Fund on Climate Change (NAFCC): Established in 2015 to provide financial assistance to state governments for implementing adaptation projects in various sectors.

State Action Plan on Climate Change (SAPCC):

  • Encourages all states and union territories to prepare their own SAPCCs based on their specific needs and priorities.
  • Aligned with the objectives of the NAPCC and the NDC.


MODIS stands for the Moderate Resolution Imaging Spectroradiometer. It is an instrument aboard two Earth-observing satellites operated by NASA, namely Aqua and Terra. The MODIS instruments were designed to provide valuable data for studying the Earth’s land, ocean, and atmosphere. MODIS is one of the key instruments used in remote sensing, providing detailed and high-quality observations of the planet’s surface and atmosphere.

Some key features and capabilities of MODIS include:

  • Multispectral Imaging: MODIS measures reflected solar radiation in multiple spectral bands, allowing it to capture data in various wavelengths of light. This capability enables researchers to observe different features and phenomena on Earth’s surface with high precision.
  • High Spatial Resolution: MODIS provides moderate to high spatial resolution imagery, allowing researchers to discern features as small as 250 meters on the Earth’s surface.
  • Global Coverage: Both Aqua and Terra satellites carrying MODIS orbit the Earth pole-to-pole, providing complete coverage of the planet every 1 to 2 days. This frequent revisit time is essential for tracking dynamic environmental processes and changes over time.
  • Applications: MODIS data is used for a wide range of applications, including monitoring vegetation health, land use and land cover changes, wildfire detection, sea surface temperature measurement, monitoring ocean color and phytoplankton distribution, and studying atmospheric aerosols and clouds, among others.
  • Climate and Environmental Studies: MODIS data plays a crucial role in climate research, allowing scientists to study long-term trends, climate change impacts, and variations in Earth’s ecosystems.


Q.1(a) What is the primary driver behind observed changes in ocean color over the two decades?

(a) Phytoplankton population fluctuations

(b) Subtle changes in ocean salinity

(c) Greenhouse gas emissions and climate change

(d) Solar radiation variations


Q.2 Which satellite instrument was used to monitor ocean color and phytoplankton distribution in the study’s long-term data analysis?






Q.3 Elaborate on the role of climate change in driving observed changes and its potential impact on marine life and carbon sequestration.

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