Week 6

Hi, all. Welcome back to WTW. Last week, I wrote about climate change. In case you missed it, we covered the theoretical and experimental case for human-caused climate change. This week's post is the sequel; we will go over what climate change means for plants and water. Before I begin, I should mention that I don't have any particular experience on climatology, but here's the best of my understanding. 

Plants, like all living organisms, need water. Humans need plants, and thus, need plants to ensure that plants get enough water. Land plants get the majority of their water from two sources: the soil and precipitation. 

Increasing the temperature increases evaporation. In wet and cool areas, water is able to accumulate in the atmosphere. However, in dry and hot areas like Arizona, water does not accumulate in the atmosphere, but falls as precipitation. This makes precipitation much more sporadic, which causes devastating rains and droughts. Ignoring seasonal variation, plants (especially crop plants) tend to not be able to store water, meaning they need about the same amount of water on each day. 

Inconsistent patterns of precipitation present a problem because when it does rain, a lot of the water evaporates before it can percolate into groundwater reservoirs and, when it doesn't rain, plants have to draw water from the soil. However, in much of the West (where there are weird incentives from the federal government to grown plants), the soil is dry and has to be irrigated. That irrigation water comes from groundwater reservoirs, which are on net losing water. This has caused the state of California to literally sink. Additionally, plants need more water in hotter conditions (because they are losing more water both to evaporation and to transpiration), making this strain on groundwater even more pronounced.  If we also consider that the sporadic precipitation also affects other water sources, then depleting groundwater reservoirs appear to be even scarier. 

Several solutions to climate change have been proposed including removing carbon dioxide from the atmosphere, capping carbon dioxide emissions, preparing people for drought. All of these should be done. 

However, I think they need to be accompanied also by a change in mindset. People who do not believe that humans are causing climate change (and not in the sense that humans are making up this hoax) posit that climate change could be part of a natural process. If that is true, it should be them who are advocating the hardest for research on how to mitigate the effects on climate change because we would have no easy outs like cutting emissions or even removing carbon from the atmosphere. They aren't doing that. Their position is untenable without the notion that the Earth will naturally restore itself to conditions amiable to humans.  They believe that it is certain that the Earth will be hospitable to humans. 

If there is one thing I would like you to take away from this post it is that the problem is probabilistic (e.g. the chance that a certain year will be a drought for a certain region). This means that our mindset also needs to be probabilistic. The goal of science and engineering has be to decrease the chances of a drought or increase the chances that a drought won't be devastating. 

While clearly skeptics aren't understanding the probabilistic nature of the problem, I am not sure believers do either. While the skeptics' position that there is a change that will be balanced is untenable, I think it is equally as silly to believe that there is a balance to be changed; that is to say that there are natural conditions that are hospitable to humans that humans are ruining. The Earth is a hard place to live. There are uncountable dangers to the survival of any species including humans (the geologic record bears this out). We can't work towards preserving a natural balance. We need instead to work towards increasing the probability of human survival. 


I am not sure what impact changing our outlook might have, but I believe that it is the first step towards building a wider consensus.
As long as people fail to see the problem probabilistically, I can't see any way for everyone to agree. 

Thanks for reading, WTW. I'm sorry if the post depressed you, but I have some good news. Next week, I will be writing about my time at the Garden. This means literally talking about flowers and butterflies.