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FRINATEK-Fri prosj.st. mat.,naturv.,tek

Quantifying past and future sea level changes in Norway

Alternative title: Kvantifisering av havnivåendringer langs norskekysten i fortid og framtid

Awarded: NOK 10.1 mill.

Project Manager:

Project Number:

303594

Application Type:

Project Period:

2020 - 2025

Partner countries:

The QUANTSEA-project is developing results that will be used to improve century-scale sea-level projections for the Norwegian coast. Understanding future sea-level change in Norway requires estimates of future ice sheet melt and knowledge of future movements of Earth's crust. In 2023, the project focussed on data collection from study sites in Finnmark, Nordland, Agder and Rogaland. Data was collected from: i) lakes and bogs, which were connected to the sea thousands of years ago, and ii) salt marshes and lagoons, which are sensitive recorders of sea-level changes during the past few decades to millennia. The results have been combined with previously published data and comprise a new relative sea-level database for Norway. In addition, new earth and ice sheet models have been integrated into geophysical modelling that is calibrated against the new database. Results of model analysis in 2024 will improve our understanding of Earth’s crustal motion, which will be utilized to generate revised sea-level forecasts for the next century and beyond. Understanding the impacts of sea-level rise and generating accurate forecasts of future sea-level change, will provide critical information for sustainable adaptation strategies to climate change.

Improving knowledge of the vulnerability of coastal Norway to future sea-level rise requires quantifying uncertainties in projected future sea surface heights and vertical land motions (derived from glacial isostatic adjustments (GIA)). The proposed research will use new, state-of-the-art GIA modelling to increase understanding of the magnitude and uncertainty of future vertical land motions across Norway, and to quantify and reduce uncertainty in century-scale relative sea-level (RSL) projections. The study aims to address significant knowledge gaps in past and present RSL change, which constitute critical benchmarks for the validation of state-of-the-art GIA models. Further, the research will explore former periods of RSL rise, i.e. paleo-analogues, in order to place the effects of anthropogenic climate change in a long-term context and to determine how future transgressions may impact coastal systems. Three Working Groups are proposed. Working Group 1 will determine the nature, rate, magnitude, and impact of recent RSL change (i.e. last two millennia) by integrating new proxy data collected from shallow marine areas and salt marshes with previously reported tide gauge records. Working Group 2 will develop new, high-resolution reconstructions of two enigmatic postglacial RSL transgressions in order to better understand former vertical land motions and the impact of past RSL rise on coastal systems. Working Group 3 will develop a GIA model based on a new RSL database generated by Working Groups 1 and 2, and will use the model to calculate present-day vertical land motion, better understand how GIA influences sea surface height, and reduce uncertainty in RSL projections along the Norwegian coast over the next century and beyond. Results from the proposed research will quantify knowledge of climate change impacts on coastal Norway and Fennoscandia, and will contribute to the development of sustainable adaptation strategies.

Funding scheme:

FRINATEK-Fri prosj.st. mat.,naturv.,tek