Sea ice lows high on the agenda – European Space Agency

Report on Arctic Sea Ice Trends and Satellite Monitoring Initiatives

Introduction

Recent satellite observations indicate that Arctic sea ice extent remains near record lows for this time of year, highlighting a persistent and concerning trend. This issue is central to discussions at the European Space Agency’s (ESA) Living Planet Symposium in Vienna, where the vital contributions of ESA’s Climate Change Initiative (CCI) Sea Ice Project and the CryoSat mission are emphasized. These efforts align closely with the United Nations Sustainable Development Goals (SDGs), particularly SDG 13 (Climate Action) and SDG 14 (Life Below Water), by enhancing understanding and monitoring of climate change impacts on polar environments.

Satellite Monitoring of Polar Regions

Satellites equipped with radar instruments provide year-round data on the remote Arctic and Antarctic regions, which experience extended periods of darkness during winter months. This continuous monitoring supports SDG 9 (Industry, Innovation, and Infrastructure) by leveraging advanced space technologies to observe Earth’s critical systems.

• Decades of satellite data reveal natural seasonal cycles of sea ice growth and decline.
• Data also document the accelerating effects of climate change on polar sea ice, a key indicator of global environmental health (SDG 13).

Role of Sea Ice in the Climate System

Sea ice influences the climate by regulating sunlight absorption and ocean temperatures. Its decline leads to increased ocean heat absorption and changes in salinity, which affect ocean circulation and global weather patterns. The Arctic region, warming faster than any other on Earth, exemplifies the concept of Arctic amplification with worldwide climatic implications.

1. Reduction in sea ice increases ocean heat absorption, contributing to global warming.
2. Changes in water temperature and salinity alter ocean currents, impacting weather systems globally.
3. These dynamics underscore the importance of climate action under SDG 13.

ESA’s Climate Change Initiative Sea Ice Project

The ESA CCI Sea Ice Project compiles datasets from multiple satellite missions, including CryoSat and Copernicus Sentinel-3, to predict future sea ice conditions, especially during the Arctic minimum in September. These datasets support long-term climate monitoring and inform policy decisions, advancing SDG 13.

• Development of the longest consistent time series of sea ice thickness from the mid-1990s to present.
• Integration of radar altimeter data enhances understanding of sea ice dynamics and vulnerability.
• New projects focus on sea ice types, age, and drift to capture complex processes affecting ice conditions.

Legacy and Impact of the CryoSat Mission

Launched over 15 years ago, ESA’s CryoSat mission continues to provide critical data on ice sheet margins and floating sea ice using innovative synthetic aperture interferometric radar altimetry. This mission supports SDG 9 by demonstrating technological innovation in Earth observation.

Recent Scientific Insights

A recent study published in the Annals of Glaciology utilized CryoSat data to analyze interannual changes in Arctic sea ice volume, driven by drift, growth, and melt processes. These findings highlight the dynamic nature of polar ice and the importance of sustained satellite monitoring for climate science and policy.

Future of Polar Monitoring: The CRISTAL Mission

Recognizing the finite lifespan of CryoSat, ESA is developing the CRISTAL (Copernicus Polar Ice and Snow Topography Altimeter) mission to continue and enhance polar monitoring capabilities. CRISTAL will carry the first Ku/Ka dual-frequency radar altimeter, enabling simultaneous measurement of sea ice thickness, snow depth, and ice-sheet elevation, thereby improving data accuracy and supporting SDG 13.

• CRISTAL consists of two identical satellites to ensure data continuity into the 2040s.
• The dual-frequency altimeter will directly measure snow depth, reducing uncertainties in sea ice thickness estimates.
• Assembly of the first satellite, CRISTAL-A, is underway at Airbus Defence and Space in Germany.

Conclusion

The ongoing and future satellite missions by ESA play a crucial role in monitoring Arctic sea ice trends, providing essential data to address climate change challenges. These efforts contribute directly to achieving the Sustainable Development Goals by enhancing climate action, fostering innovation, and protecting marine ecosystems.

1. Sustainable Development Goals (SDGs) Addressed or Connected

1. SDG 13: Climate Action
   • The article focuses on monitoring Arctic sea ice decline, a direct consequence of climate change.
   • It highlights the role of satellite missions in understanding climate impacts and supporting policy-making.
2. SDG 14: Life Below Water
   • The article discusses changes in ocean temperature and salinity due to sea ice melt, affecting marine ecosystems.
   • It emphasizes the importance of monitoring polar oceans and their ice cover.
3. SDG 9: Industry, Innovation and Infrastructure
   • The development and deployment of advanced satellite technologies such as CryoSat and CRISTAL demonstrate innovation in Earth observation infrastructure.

2. Specific Targets Under Those SDGs Identified

1. SDG 13: Climate Action
   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters.
   • Target 13.3: Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction, and early warning.
2. SDG 14: Life Below Water
   • Target 14.3: Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels.
3. SDG 9: Industry, Innovation and Infrastructure
   • Target 9.5: Enhance scientific research, upgrade the technological capabilities of industrial sectors, including encouraging innovation and increasing the number of research and development workers.

3. Indicators Mentioned or Implied to Measure Progress

1. Sea Ice Extent and Thickness
   • Satellite data from CryoSat, Sentinel-3, ERS-2, Envisat, and future CRISTAL missions provide measurements of sea ice thickness and extent over time.
   • These data sets form long-term consistent time series that track changes in sea ice volume and thickness, key indicators of climate change impact.
2. Sea Ice Volume Budget and Dynamics
   • Studies using satellite data analyze sea-ice drift, growth, and melt to understand interannual changes in sea-ice volume.
3. Snow Depth on Sea Ice
   • The upcoming CRISTAL mission will measure snow depth over sea ice, improving accuracy of sea ice thickness estimates.
4. Greenhouse Gas Emission Scenarios
   • Models based on different greenhouse gas emission scenarios are used to predict future sea ice conditions, indirectly linking to climate action indicators.

4. Table of SDGs, Targets, and Indicators

Source: esa.int