Understanding Changes in Iceland’s Streamflow Dynamics in Response to Climate Change

Anthropogenic climate change is profoundly altering the hydrological cycle in high-latitude regions. Iceland, with its abundant hydrological and glaciological data, provides a unique opportunity to study the effects of climate change on streamflow in snow- and glacier melt dominated catchments. The country's reliance on hydropower, as the top electricity producer per capita globally, highlights the critical need for understanding these changes.

In Iceland, the average temperature has risen significantly in recent decades, outpacing the global warming trend. Despite this warming, increased precipitation has led to more extensive snow cover and depth in some regions. Glaciers have experienced a loss in area and mass, soil temperatures have risen, and vegetation has increased. However, the impacts of these environmental shifts on streamflow remain largely unexplored.

Our study utilizes the newly released LamaH-Ice dataset, encompassing streamflow observations from mainly undisturbed watersheds, atmospheric forcings from climate reanalyses and catchment characteristics, to investigate Iceland's streamflow dynamics changes over recent decades. We analyze annual, seasonal, and monthly streamflow volumes, spring freshet timing, and extreme flow events, correlating these changes with environmental conditions and catchment attributes.

The results suggest that streamflow regime alterations are influenced by multiple factors, including geographic location, topography, and river type. The findings offer crucial insights into Iceland's hydrological changes amid rapid climatic shifts, with broader implications for reservoir operations and water resource management. This study not only enhances our understanding of Icelandic hydrology but also contributes to global knowledge on climate-induced hydrological changes.