The oceans and cryosphere during climate change

Our knowledge and understanding of how the Earth’s complex climate system works have improved significantly. We are now able to identify the causes of natural fluctuations in the climate system and substantiate humankind’s contribution to global warming.

However, despite all this, there are still gaps in climate research. We lack important data, especially from deeper ocean layers and polar regions, to help us explain long-term climatic fluctuations and developments. The oceans, which cover 70 percent of the Earth’s surface, play a particularly critical role here. Since the Industrial Revolution, they have absorbed 30 percent of anthropogenic carbon dioxide and 90 percent of the heat resulting from the increase in greenhouse gases.

It is already clear that human-induced climate change is noticeably changing the oceans, making them warmer and more acidic. And climate change is shifting the balance in the world of ice sheets and glaciers, for example, because melting bodies of ice are causing sea levels to rise and changing ocean currents. Helmholtz researchers therefore want to shed light on the mechanisms by which the oceans and the cryosphere respond to global warming and how they affect the climate – from the past to the present and into the future. The term cryosphere covers all areas of the Earth in which water occurs in the form of ice or snow – i.e., sea ice, snow, glacial ice, and permafrost.

We are researching the impact of climate change on temperature distribution, carbon storage, and nutrient cycles in the oceans and on the extent of sea ice. For this purpose, we use data from the Arctic, collected by the research vessel Polarstern on the MOSAiC expedition. Off the coast of Northwest Africa, we are also working with our partners to investigate what the consequences of water rising from the deeper layers of the ocean to the near-surface layer may be for phytoplankton and, ultimately, for fishing and the local population’s food supply. We are planning a joint US–German research partnership for 2027, through which we hope to study the impact of global warming on the world’s seas and permanent ice cover more precisely. Our scientific findings will subsequently feed into the reports produced by the renowned Intergovernmental Panel on Climate Change (IPCC). In this way, we support decision-making by political stakeholders around the world by providing sound scientific facts.

 

 

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“So far, we lack important data, especially from deeper ocean layers and polar regions, to help us explain long-term climatic fluctuations and developments. We will collect and evaluate this data in collaboration with international partners by means of extensive studies, expeditions, and modeling.”

Topic-Speaker: Gerrit Lohmann, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

E-mail: gerrit.lohmann(at)awi.de

Topic-Support: Almut Schmengler, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung