What Are Direct and Indirect Effects of Climate Change?

Freshwater systems provide usable water for technological development, agriculture and human consumption, while also serving as habitats for various aquatic species. Therefore, freshwater systems are of crucial economic and ecological value. A 2021 study titled, ” “The Importance of Indirect Effects of Climate Change Adaptations On Alpine and Pre-Alpine Freshwater Systems” asserts that human-made transformations in water hydrology and pollution from sewer outflows and agriculture chemicals are threats to freshwater systems. Properly accounting for the effects of climate change and anthropogenic influence on aquatic environments will hopefully improve climate change adaptation policies.

What Is Freshwater?

Rivers, reservoirs, and streams are examples of freshwaters systems. Freshwater is a subset of Earth’s water which is significantly less salty than marine waters (like seas and oceans). The United States Geological Survey, a branch dedicated to science within the United States Department of the Interior, defines freshwater as “water containing less than 1,000 milligrams per liter of dissolved solids, most often salt.” Though freshwater is renewed through the water cycle, it is a finite resource. If freshwater is used more quickly than it is naturally replenished, water security risks may be enhanced.

What Are Direct and Indirect Effects of Climate Change?

Authors of “The Importance of Indirect Effects of Climate Change Adaptations On Alpine and Pre-Alpine Freshwater Systems”, regard higher frequency of extreme meteorological events and increased temperatures as “direct effects” of climate change. These direct effects adversely influence the state and quality of aquatic regions. Direct effects also interact with human responses to climate change and produce “indirect effects”.

So-called indirect effects refer to human practices that are aimed at climate change mitigation. Indirect effects include land-use changes, alterations to freshwater systems and increasing irrigation practices. Authors suggest that “indirect effects may, at least in the short term, overrun the impact of direct climate change on water bodies.” Though all biomes are predicted to be impacted by climate change, freshwater systems in alpine and pre-alpine regions may be disproportionately at risk due to agriculture and hydropower plants.

Adapting Water Management to Climate Change

Freshwater use for the production of energy, also known as hydropower, is typically made possible by dams and in-stream structures. Hydropower infrastructure generates usable electricity for homes and businesses. Authors of the 2021 review article posit that hydropower is used as an alternative to nonrenewable energy resources. Hydropower production is therefore considered an adaptation strategy to climate change. Hydropower installations in freshwater networks can fragment or isolate certain species populations which are ill-adapted for the changes in water flow and perpetuate biodiversity loss. By modifying the hydrology of freshwater systems, water usage for energy production can compound the direct effects of climate change to aquatic flora and fauna.

How Does Agriculture Affect Climate Change?

Agriculture can be of detriment to freshwater systems as well, but in a much different way than hydropower plants. Climate change can intensify extreme weather event trends, such as floods, storms and droughts; these effects can drive diminished crop yields. In the interest of mitigating threats to crops brought on by climate change, agriculturalists may expand irrigation infrastructure or enhance fertilizer use. These adaptations can exacerbate the consequences which are already affecting crop growth cycles.

What Is the Impact of Climate Change On Water Resources?

Authors of the 2021 review claim that “rain-fed dairy farming is currently the most predominant form of agriculture, but in the future these grasslands may become more and more dependent on irrigation”. Redirecting water for irrigation use can potentially limit the quantity of water available in freshwater ecosystems. Variability in weather regimes may contribute to further dependence on water from irrigation (rather than from rainfall) in the future. Some of the responses that agriculturalists are expected to as a response to a changing climate pose risks to freshwater systems. Policy makers must account for indirect impacts to alleviate worsening the ecological status and water quality within aquatic environments.

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