Globally widespread and increasing violations of environmental flow envelopes
Human actions and climate change have drastically altered river flows across the world, resulting in adverse effects on riverine ecosystems. Environmental flows (EFs) have emerged as a prominent tool for safeguarding the riverine ecosystems, but at the global scale, the assessment of EFs is associated with high uncertainty related to the hydrological data and EF methods employed. Here, we present a novel, in-depth global EF assessment using environmental flow envelopes (EFEs). Sub-basin-specific EFEs are determined for approximately 4400 sub-basins at a monthly time resolution, and their derivation considers the methodological uncertainties related to global-scale EF studies. In addition to a lower bound of discharge based on existing EF methods, we introduce an upper bound of discharge in the EFE. This upper bound enables areas to be identified where streamflow has substantially increased above natural levels. Further, instead of only showing whether EFs are violated over a time period, we quantify, for the first time, the frequency, severity, and trends of EFE violations during the recent historical period.
Discharge was derived from global hydrological model outputs from the ISIMIP 2b ensemble. We use pre-industrial (1801–1860) quasi-natural discharge together with a suite of hydrological EF methods to estimate the EFEs. We then compare the EFEs with recent historical (1976–2005) discharge to assess the violations of the EFE. These violations most commonly manifest as insufficient streamflow during the low-flow season, with fewer violations during the intermediate-flow season, and only a few violations during the high-flow season. The EFE violations are widespread and occur in half of the sub-basins of the world during more than 5 % of the months between 1976 and 2005, which is double compared with the pre-industrial period. The trends in EFE violations have mainly been increasing, which will likely continue in the future with the projected hydroclimatic changes and increases in anthropogenic water use. Indications of increased upper extreme streamflow through EFE upper bound violations are relatively scarce and dispersed. Although local fine-tuning is necessary for practical applications, and further research on the coupling between quantitative discharge and riverine ecosystem responses at the global scale is required, the EFEs provide a quick and globally robust way of determining environmental flow allocations at the sub-basin scale to inform global research and policies on water resources management.
General news | 2023-09-19
New Google.org grant funds Centre research on AI-powered climate risk tool
Google.org has awarded five million US dollars to a group of scientists, including Centre researchers, to develop and scale ClimateIQ , an artificial intelligence-powered climate risk evaluation tool for cities
General news | 2023-09-19
Researchers and chefs team up for a sustainable lunch week
“Risotto on Swedish oat-rice, with apple cider vinegar, blue mussels from Bohuslän, parsley, and grated Svecia cheese”. That’s one of the science-cooked dishes that guests can enjoy at “A Planetary Lunch” — an experimental lunch week at Stockholm university
Research news | 2023-09-14
The SDGs are not on track — new report outlines what needs to happen
Humanity is set to miss the Sustainable Development Goals. But decisive and timely policy actions can kickstart extraordinary turnarounds and a giant leap toward achieving the SDGs
Research news | 2023-09-13
All planetary boundaries mapped out for the first time, six of nine crossed
For the first time, an international team of scientists is able to provide a detailed outline of planetary resilience by mapping out all nine boundary processes that define a safe operating space for humanity.
General news | 2023-09-04
Centre secures 28 MSEK research funding in two new Formas grants
The two grants worth 14 million SEK each will focus on the intersection of climate, water and biodiversity
General news | 2023-08-30
Science and music met as Centre research was presented in a concert at the Baltic Sea Festival
“Dialogues” premiered – a piece of music written about Carolin Seiferth’s PhD research