The importance of indirect effects of climate change adaptations on alpine and pre-alpine freshwater systems

Feature photo edited from © Martin Laurenceau

In their latest Perspective, Morgane Brosse and colleagues delve into the impact of human efforts to reduce or mitigate climate change, its effects on alpine freshwater environments and the role of specific management and policy decisions in determining the nature of these impacts.

In an effort to address the threat of global change, much pressure is put on shifting from fossil fuels to renewable energy, and to adapt economic sectors such as agriculture to new climatic conditions. But often ignored is the fact that these human adaptations could have indirect impacts on freshwater as strong as, or faster than, climate change.

In the worst case scenario, we think these adaptations may be able to interact with and amplify the direct effects of climate change to dramatic extents. On the other hand, they may instead be used to mitigate some of the climate-change effects.

Our Perspective is an offshoot of a multi-disciplinary study involving a systematic review as well as interviews with many experts and stakeholders from Switzerland, the “water castle” of Europe. This research project was mandated by the Hydro-CH18 program in order to understand the impact of climate change on water resources in Switzerland, and was supported by the Swiss Federal Office for the Environment.

In our article, we focus on two examples of high socio-economic and ecological relevance: hydropower and agriculture.

HalfFilledDam_compressed — The Vercasca Dam lake in Ticino/Switzerland is a typical example of water storage for hydroelectricity. Increasing shifts to hydroelectricity have direct negative effects on aquatic organisms, yet the effect size (and possible mitigation) depends on if and how much residual flow is maintained © Florian Altermatt

Hydropower

Climate-induced drought can foster conflicts between the production of energy by (big and small) hydropower plants and ecosystem survival. Lower water flow downstream of hydropower structures increases water temperature, desiccation and environmental fragmentation, in turn promoting diseases and provoking loss of genetic diversity and vulnerability to invasive species, etc – all of which are already direct outcomes of climate change.

Thus, while some small hydropower plants are implemented to produce renewable energy, their negative effects on biodiversity further reinforce those of climate change. However, we can mitigate or resolve these conflicts with sensitive water management and compromises, retaining sufficient water flows at all times as well as retaining meltwater to bridge eventual drought periods.

Small hydropower plants in particular are often not beneficial for mitigating climate change and have overproportionate negative impacts on biodiversity. However, if altitude dams become water reservoirs in areas where glaciers are shrinking, sustainable water regulation can provide sufficient water for all utilizations throughout the year and avoid biodiversity loss.

Agriculture

Agriculture also drastically affects freshwater environments via water exploitation, land conversion and pollution. Combination with changing climatic events can also lead to other impacts such as severe pollution peaks in water bodies.

Fortunately, we can control the human aspects and greatly reduce their impact by optimizing irrigation and water-saving methods, reducing fertilizer and pesticide application, and shifting to crops and livestock more adapted to changing seasons and climatic conditions. To do so effectively, regulations and incentives (mostly financial subsidies) must be aligned to have less or no adverse effects on biodiversity and freshwater systems. In fact, sensible water policies can both reduce water exploitation and preserve existing water resources.

Fig3_blog-page-001 — Combination of human activities and climate change on freshwater environments in alpine and pre-alpine settings. We focus here on hydropower and agriculture. Items in purple show human influences and where regulations and incentives must be encouraged

We must indisputably and urgently take measures to stop climate change and to reduce its direct effects on all ecosystems, but we must also carefully assess the consequences of such measures to not risk worse outcomes. If managed properly, revitalisations and sustainable land uses have potential for rapid and implementable leverage to mitigate climate change effects on aquatic ecosystems. It is crucial to work with policy- and decision-makers, and to consider these human effects in restoration planning and relevant sectorial policies.

Read the full article: “The importance of indirect effects of climate change adaptations on alpine and pre-alpine freshwater systems” in Issue 3:1 of Ecological Solutions and Evidence.