Forests, water quality, and climate change

I know that nature provides great water filtration. I’ve read studies and reports about how restoring wetlands improves water quality and can cost less than building a water filtration plant to produce the same results. I haven’t considered how much filtration forests do before. It makes perfect sense though.

Any time you have water moving through plants, the plants are likely going to help filter it. This is because the roots of the plants pull up water but they also pull up nutrients like phosphorus and nitrogen. They create chemical bonds to use these nutrients themselves, thereby reducing the amount in the water.

Plants love both nitrogen and phosphorus. They are found in most fertilizers. So when high levels of these chemicals end up in water through things like agricultural runoff they cause lots of growth of things like algae in the water. This makes it harder for water filtration systems to clean the water enough for drinking.

So deforestation is bad, but now with us already seeing impacts from climate change on forests and expectations based on scientific modelling of high levels of forest die off we can expect that our water is going to get harder to clean. These are the findings of Kong et al 2022. The impacts of deforestation were more significant than that of climate change warming the water body directly.

I know there is always a discussion of the costs of reducing climate change, but research like this illustrates that there are going to be many costs that come if we don’t address climate change now. Do we really want to count on these costs being less than the spending we would have to do now?