Diffuse hydrological mass transport through catchments: scenario analysis of coupled physical and biogeochemical uncertainty effects

This paper quantifies and maps the effects of coupled physical and biogeochemical variability on diffuse hydrological mass transport through and from catchments. It further develops a scenario analysis approach and investigates its applicability for handling uncertainties about both physical and biogeochemical variability and their different possible cross-correlation. The approach enables identification of conservative assumptions, uncertainty ranges, as well as pollutant/nutrient release locations and situations for which further investigations are most needed in order to reduce the most important uncertainty effects. The present scenario results provide different statistical and geographic distributions of advective travel times for diffuse hydrological mass transport. The geographic mapping can be used to identify potential hotspot areas with large mass loading to downstream surface and coastal waters, as well as their opposite, potential lowest-impact areas within the catchment. Results for alternative travel time distributions show that neglect or underestimation of the physical advection variability, and in particular of those transport pathways with much shorter than average advective solute travel times, can lead to substantial underestimation of pollutant and nutrient loads to downstream surface and coastal waters. This is particularly true for relatively high catchment-characteristic product of average attenuation rate and average advective travel time, for which mass delivery would be near zero under assumed transport homogeneity but can be orders of magnitude higher for variable transport conditions. A scenario of high advection variability, with a significant fraction of relatively short travel times, combined with a relevant average biogeochemical mass attenuation rate, emerges consistently from the present results as a generally reasonable, conservative assumption for estimating maximum diffuse mass loading, when the prevailing physical and biogeochemical variability and cross-correlation are uncertain

Arctic wetland system dynamics under climate warming

Warming and hydrological changes have already affected and shifted environments in the Arctic. Arctic wetlands are complex systems of coupled hydrological, ecological, and permafrost-related processes, vulnerable to such environmental changes. This review uses a systems perspective approach to synthesize and elucidate the various interlinked responses and feedbacks of Arctic wetlands to hydroclimatic changes. Starting from increased air temperatures, subsequent permafrost thaw and concurrent hydrological changes are identified as key factors for both shrinkage and expansion of wetland area. Other diverse factors further interact with warming, hydrological changes, and permafrost thaw in altering the Arctic wetland systems. Surface albedo shifts driven by land cover alterations are powerful in reinforcing Arctic warming, while vegetation-related factors can balance and decelerate permafrost thaw, causing negative feedback loops. With the vast amounts of carbon stored in Arctic wetlands, their changes in turn affect the global carbon cycle. Overall, the systems perspectives outlined and highlighted in this review can be useful in structuring and elucidating the interactions of wetlands with climate, hydrological, and other environmental changes in the Arctic, including the essential permafrost-carbon feedback. This article is categorized under: Water and Life > Nature of Freshwater Ecosystems Water and Life > Stresses and Pressures on Ecosystems Science of Water > Water and Environmental Change

Estimation of permafrost thawing rates in a sub-arctic catchment using recession flow analysis

Permafrost thawing is likely to change the flow pathways taken by water as it moves through arctic and sub-arctic landscapes. The location and distribution of these pathways directly influence the carbon and other biogeochemical cycling in northern latitude catchments. While permafrost thawing due to climate change has been observed in the arctic and sub-arctic, direct observations of permafrost depth are difficult to perform at scales larger than a local scale. Using recession flow analysis, it may be possible to detect and estimate the rate of permafrost thawing based on a long-term streamflow record. We demonstrate the application of this approach to the sub-arctic Abiskojokken catchment in northern Sweden. Based on recession flow analysis, we estimate that permafrost in this catchment may be thawing at an average rate of about 0.9 cm/yr during the past 90 years. This estimated thawing rate is consistent with direct observations of permafrost thawing rates, ranging from 0.7 to 1.3 cm/yr over the past 30 years in the region

Cross-Scale Water and Land Impacts of Local Climate and Energy Policy—A Local Swedish Analysis of Selected SDG Interactions

This paper analyses how local energy and climate actions can affect the use of water and land resources locally, nationally and globally. Each of these resource systems is linked to different Sustainable Development Goals (SDGs); we also explore related SDG interactions. A municipality in Sweden with the ambition of phasing out fossil fuels by year 2030 is used as illustrative case example. The local energy system is modelled in detail and indirect water and land requirements are quantified for three stylised decarbonisation scenarios of pathways to meeting climate and energy requirements (related to SDG13 and SDG7, respectively). Total local, national and global implications are addressed for the use of water and land resources, which relate to SDG6 for water, and SDG2 and SDG15 for land use. We find that the magnitude and location of water and land impacts are largely pathway-dependent. Some scenarios of low carbon energy may impede progress on SDG15, while others may compromise SDG6. Data for the studied resource uses are incoherently reported and have important gaps. As a consequence, the study results are indicative and subject to uncertainty. Still, they highlight the need to recognise that resource use changes targeting one SDG in one locality have local and non-local impacts that may compromise progress other SDGs locally and/or elsewhere in the world

Hydro-climatic changes of wetlandscapes across the world

Assessments of ecosystem service and function losses of wetlandscapes (i.e., wetlands and their hydrological catchments) suffer from knowledge gaps regarding impacts of ongoing hydro-climatic change. This study investigates hydro-climatic changes during 1976–2015 in 25 wetlandscapes distributed across the world’s tropical, arid, temperate and cold climate zones. Results show that the wetlandscapes were subject to precipitation (P) and temperature (T) changes consistent with mean changes over the world’s land area. However, arid and cold wetlandscapes experienced higher T increases than their respective climate zone. Also, average P decreased in arid and cold wetlandscapes, contrarily to P of arid and cold climate zones, suggesting that these wetlandscapes are located in regions of elevated climate pressures. For most wetlandscapes with available runoff (R) data, the decreases were larger in R than in P, which was attributed to aggravation of climate change impacts by enhanced evapotranspiration losses, e.g. caused by land-use changes

Publisher Correction: Hydro-climatic changes of wetlandscapes across the world (Scientific Reports, (2021), 11, 1, (2754), 10.1038/s41598-021-81137-3)

In the original version of this Article, V. H. Rivera-Monroy was incorrectly affiliated with ‘Alexander von Humboldt Biological Resources Research Institute, Calle 28 A No. 15-09, Bogotá, DC, 70803, Colombia’. The correct affiliation is listed below. Department of Oceanography and Coastal Sciences, College of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA As a result, Affiliations 22–27 were incorrectly listed as Affiliations 21–26 respectively. The original Article has been corrected