An Initial Framework for Understanding the Resilience of Aquifers to Groundwater Pumping

Groundwater stored in aquifers experiences a wide variety of natural, induced and/or anthropogenic disturbances. Among them, groundwater extraction is the main disturbance that affects most of the aquifers in the world. Aquifer’s resilience, understood as the potential of the aquifer to sustain disturbances on the long term and to guarantee essential qualities and functions, provides a key tool when assessing sustainable groundwater management alternatives. The aim of this work is to illustrate an aquifer resilience framework that can support groundwater sustainable management. A theoretical framework is based on the identification of the key variables that parameterize the quantitative and qualitative responses of the groundwater flow system to pumping. An example from the literature based in Denmark is provided as an illustration of the proposed framework. The results show that long-term high quality data are essential to make a step further in aquifers dynamic responses. The quantitative understanding of the aquifer’s behavior before, during and after groundwater extraction provides a valuable source of information in order to identify thresholds of change (tipping points, transitions or regime shifts) which could permit pro-active groundwater management decisions. Moreover, a deeper understanding on the aquifer’s dynamics provides useful information in order to avert threats that may put the sustainability of the system at risk

Sea-level rise in Denmark: paleo context, recent projections and policy implications

We present the most recent Intergovernmental Panel on Climate Change Sixth Assessment Report (AR6) sea-level projections for four Danish cities (Aarhus, Copenhagen, Esbjerg and Hirtshals) under the Shared Socioeconomic Pathway (SSP) family of climate scenarios. These sea-level changes projected over the next century are up to an order of magnitude larger than those observed over the previous century. At these cities, year 2150 sea-level changes of between 29 and 55 cm are projected under the very low emissions scenario (SSP1-1.9), while changes of between 99 and 123 cm are projected under the very high emissions scenario (SSP5-8.5). These differences highlight the potentially significant impact of remaining opportunities for climate change mitigation. Due to this increase in mean sea level, the mean recurrence time between historically extreme events is expected to decrease. Under the very high emissions scenario, the historical 100-year storm flood event will become a 1- to 5-year event at most Danish harbours by 2100. There is considerable uncertainty associated with these sea-level projections, primarily driven by uncertainty in the future evolution of the Antarctic ice sheet and future sterodynamic changes in ocean volume. The AR6 characterises collapse of the West Antarctic ice sheet as a low-probability but high-impact event that could cause several metres of sea-level rise around Denmark by 2150. In climate adaptation policy, the scientific landscape is shifting fast. There has been a tremendous proliferation of diverse sea-level projections in recent years, with the most relevant planning target for Denmark increasing c. 50 cm in the past two decades. Translating sea-level rise projections into planning targets requires value judgments about acceptable sea-level risk that depend on local geography, planning timeline and climate pathway. This highlights the need for an overarching national sea-level adaptation plan to ensure municipal plans conform to risk and action standards

Farlige forsimplinger

I temanummeret om klima i GeologiskNyt nr. 2 bragte vi bl.a. en artikel af Ole Humlum fra Institutt for geofag, Oslo Universitet: Klima og CO2. Det følgende indlæg kommenterer denne artikel

A hydrological early warning system for Denmark based on the national model

The rapidly increasing impacts of climate change are likely to require changes in relevant institutions (IPCC 2012). An example is the growing need for immediate information on the entire water cycle (Fig. 1), with quantitative assessments of critical hydrological variables and flow interactions between different domains, e.g. atmosphere, plant-soil, surface water, groundwater and the sea, as they take place