Climate Change and the Polar Oceans

Research in the Department Physical Oceanography, University of Bremen

The changes in the Polar Oceans caused by global warming have a major impact on the further evolution of climate change. Therefore, polar ocean research is enormously important. For example, increasingly warmer ocean waters are accelerating melting at the base of the Antarctic ice shelf and glacier tongues in the fjords of Greenland, contributing to sea level rise. If the meltwater reaches certain key regions in the ocean and dilutes salinity there, the formation of deep and bottom waters that drive global oceanic overturning can be weakened. If less surface water is converted to deep and bottom water, the ocean’s uptake of greenhouse gases from the atmosphere is reduced, which has previously slowed climate change. Furthermore, oceanic overturning regulates and stabilizes the global climate. Its weakening can lead to drastic changes, the extent of which depends primarily on how human emissions of greenhouse gases will develop.
In the Arctic Ocean, the retreat of sea ice may bring warm water coming from the Atlantic Ocean to the surface from depths of 200 – 400 meters, further accelerating ice melt. This is called Atlantification of the Arctic. To better understand the changes in the polar oceans, extensive measurements must be made over a long period of time and many open questions must be answered. Through oceanographic measurements at key locations, we are working to address the following research questions.

Research questions

  • How is bottom and deep water formation changing in Antarctica and the subpolar North Atlantic?
  • How is increasing Greenland ice melt impacting deep ventilation and global oceanic overturning?
  • How are sea ice and ice shelf interactions with light, warm water masses and with cold, heavy water masses changing in Antarctica?
  • What are the implications of decreasing sea ice for Arctic Ocean dynamics?


  • Measurements and analysis of helium and neon isotopes to calculate fractions of submarine meltwater and to estimate the formation of sea ice.
  • Measurements and analysis of CFCs and SF6 to determine the age of water and to find distribution pathways, as well as to calculate the storage of anthropogenic carbon.
  • Combination with other parameters (temperature, salinity, oxygen, velocity, turbulence)

Responsible persons

Dr. Oliver Huhn, Institute of Environmental Physics, University of Bremen

Dr. Maren Walter, Institute of Environmental Physics and MARUM, University of Bremen

Projects we participate in

GROCE – Greenland Ice Sheet Ocean Interaction

Estimate of submarine meltwater in northeast Greenland
– From marine terminating glaciers along the boundary current into the Nordic Seas

SPP Sealevel (SPP1889) – Regional Sea Level Change and Society

LabSea Melt

Estimates of basal melt water from Greenland: a driver for sea level changes

(AC)3 Arctic Amplification (TRR172)

C04: Coupling between atmosphere, mixed layer and pycnocline under Arctic Amplification: The role of sea ice related processes

ArcTrain (IRTG 1904)

HB06: Im­pact of va­ry­ing sea-ice co­ver on in­put of wind en­er­gy, in­ter­nal wa­ves, and mi­xing

Cluster of Excellence MARUM

Hydrothermal heat and mass fluxes in the Arctic (Gakkel Ridge)