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 is once again approaching record low levels for this time of year, highlighting a persistent and concerning trend. This issue is a focal point at the European Space Agency’s (ESA) Living Planet Symposium in Vienna, where the critical 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 polar environments.

Satellite Monitoring of Polar Regions

Satellites equipped with radar instruments provide year-round observations of the Arctic and Antarctic, regions otherwise obscured during long winter darkness. These continuous data streams enable scientists to track the natural seasonal growth and decline of sea ice and assess the impacts of climate change on these fragile ecosystems.

Role of Sea Ice in the Climate System and SDG Relevance

• Sea ice influences the Earth’s climate by regulating sunlight absorption; as ice diminishes, more sunlight warms ocean waters.
• Melting ice alters ocean salinity and temperature, affecting ocean circulation patterns that influence global weather and climate systems.
• The Arctic, warming faster than any other region, exemplifies “Arctic amplification,” with significant global implications.

These dynamics are directly related to SDG 13 (Climate Action) by highlighting the urgent need to mitigate climate change impacts and SDG 15 (Life on Land) through preserving fragile polar ecosystems.

ESA’s Climate Change Initiative Sea Ice Project

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

1. Development of the longest consistent time series of sea ice thickness data, spanning from the mid-1990s to present.
2. Analysis of trends showing sea ice becoming thinner, sparser, and more vulnerable.
3. Initiation of new projects to study sea ice types, age, and drift dynamics for comprehensive understanding.

Legacy and Innovation in Satellite Missions

• ESA’s heritage satellites ERS and Envisat, along with the 15-year-old CryoSat mission, have provided invaluable data on ice sheet and sea ice changes.
• CryoSat’s synthetic aperture interferometric radar altimeter was pioneering in measuring ice changes at polar margins.
• A recent study utilizing CryoSat data revealed dynamic interactions of sea-ice drift, growth, and melt affecting Arctic sea-ice volume over the past decade.

Future Monitoring: The CRISTAL Mission

Recognizing the finite lifespan of CryoSat, ESA is advancing the CRISTAL (Copernicus Polar Ice and Snow Topography Altimeter) mission to ensure continuity and enhancement of polar monitoring capabilities. This mission supports SDG 13 by improving climate data accuracy and SDG 9 (Industry, Innovation, and Infrastructure) through technological advancement.

• CRISTAL will carry the first Ku/Ka dual-frequency radar altimeter to measure sea-ice thickness, snow depth, and ice-sheet elevation.
• The mission consists of two identical satellites launched sequentially to maintain data continuity into the 2040s.
• Direct measurement of snow depth will reduce uncertainties in sea ice thickness estimates, enhancing data reliability for climate models and policy.
• Assembly of the first satellite, CRISTAL-A, is progressing well at Airbus Defence and Space in Germany.

Conclusion

ESA’s ongoing and future satellite missions play a pivotal role in monitoring Arctic sea ice trends, providing essential data to address the challenges posed by climate change. These efforts contribute significantly to achieving the Sustainable Development Goals by supporting informed climate action, protecting marine and terrestrial ecosystems, and fostering innovation in Earth observation technologies.

1. Sustainable Development Goals (SDGs) Addressed or Connected to the Issues Highlighted in the Article

1. SDG 13: Climate Action
   • The article focuses on monitoring Arctic sea ice decline, a direct consequence of climate change.
   • It highlights the importance of satellite data in understanding climate trends and supporting policy-making.
2. SDG 14: Life Below Water
   • The changes in sea ice affect ocean temperature, salinity, and circulation patterns, impacting marine ecosystems.
3. SDG 9: Industry, Innovation and Infrastructure
   • The development and deployment of advanced satellite missions like CryoSat and CRISTAL demonstrate innovation in Earth observation technologies.
4. SDG 17: Partnerships for the Goals
   • Collaboration among ESA, Copernicus, and scientific communities to provide data for climate monitoring and policy support.

2. Specific Targets under Those SDGs Identified Based on the Article’s Content

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 space technology for environmental monitoring.
4. SDG 17: Partnerships for the Goals
   • Target 17.6: Enhance North-South, South-South and triangular regional and international cooperation on and access to science, technology and innovation.

3. Indicators Mentioned or Implied in the Article to Measure Progress Towards the Identified Targets

1. Sea Ice Extent and Thickness
   • Satellite-derived measurements of Arctic and Antarctic sea ice extent and thickness (e.g., data from CryoSat, Sentinel-3, ERS-2, Envisat).
   • Long-term consistent time series of sea ice thickness as an essential climate variable.
2. Sea Ice Volume and Age
   • Estimates of sea ice volume budget and tracking of sea ice age and drift patterns.
3. Snow Depth on Sea Ice
   • Measurements from the upcoming CRISTAL mission’s dual-frequency radar altimeter to directly assess snow depth, improving sea ice thickness accuracy.
4. Greenhouse Gas Emission Scenarios
   • Model outputs based on different greenhouse gas emission scenarios to predict future sea ice conditions.

4. Table of SDGs, Targets and Indicators

Source: esa.int