Continuing Our Journey - Independent Study Week 2 Summary

     As we progress to chapter three of Climate Change: A Very Short Introduction, the author, Mark Maslin, discusses the evidence behind our understanding of climate change. He begins with a very powerful statement about science itself:

Science is not a belief system. It is a rational, logical methodology that moves forward by using detailed observation and experiments to constantly test and retest ideas and theories. It is the very foundation of our global society. So you cannot pick and choose which bits of scientific evidence you want to believe in and which bits you want to reject. (p.26)

This seems especially important to remember in these times and this political environment. 

     Maslin then goes on to describe the 'weight of evidence' principle - which, put simply, is the extent to which scientific evidence from multiple sources supports a given hypothesis, such as anthropogenic climate change. He then presents evidence that the scientific community has gathered in relation to climate change in four main areas: "global temperature, precipitation, sea level rise, and extreme weather events." (p.27) Maslin explains that scientists have observed an increase in all of these areas, which is consistent with the effects of greater levels of greenhouse gases in the atmosphere. Additionally, he addresses the climate change deniers, who present 'alternative causes' for the increases in these areas, by showing that science has proven that none of these 'alternative causes' can be the dominant cause of climate change. Science shows that only the modern exponential increase in greenhouse gases caused by human actions can fully explain our current climate changes. We are the dominant cause. 

     In chapter four, Maslin discusses the use of scientific modeling to predict future climate scenarios. He explains that "[t]he biggest unknown in the models is not the physics or the chemistry or the biology: it is the estimation of future global GHG emissions over the next 80 years." This makes sense because humans are hard to predict, sometimes even to themselves. Maslin states that the Earth's carbon cycle is central to the climate models. He explains: "The Earth's carbon cycle is complicated, with both large sources and sinks of CO2. Currently half of all our carbon emissions are absorbed by the natural carbon cycle and do not end up in the atmosphere but rather in the oceans and the terrestrial biosphere." (p.47) However, as we discussed before, these sinks will begin to take on less carbon as we warm the planet and continue to degrade the land. Maslin also describes how climate models account for both warming effects, such as greenhouse gas emissions, and cooling effects, such as aerosols and clouds. 

     After explaining how the climate models work, he then presents the shared socioeconomic pathways (SSPs) that the IPCC uses while modeling for the future. There are five pathways: 

SSP1: Sustainability -- taking the green road...In this scenario the world shifts gradually but continually towards a more sustainable path, with inclusive and environmentally aware economic development. (p.51)

SSP2: Middle of the road...In this scenario the world follows a path in which social, economic, and technological trends do not shift markedly from historical patterns. (p.52)

SSP3: Regional rivalry -- a rocky road...In this scenario there is a resurgence of nationalism. concerns about competitiveness and security, and regional conflicts that push countries to increasingly focus on domestic or, at best, regional issues. (p.52)

SSP4: Inequality -- a road divided...In this scenario there are highly unequal investments in human capital, combined with increasing disparities in economic opportunity and political power, lead to increasing inequalities and stratification both across and within countries. (p.53)

SSP5: Fossil-fuelled development -- taking the highway...In this scenario the world places increasing faith in competitive markets, innovation, and participatory societies to produce rapid technological progress and development of human capital as the path to sustainable development. (p.53)

These five shared socioeconomic pathways are then combined with five potential representative concentration pathways (RCP) -- future greenhouse gas concentration assumptions and the radiative forcing they may cause -- to provide the most likely scenarios: SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, which the IPCC focus on. (p.54) Understanding this information can make it easier for us to read IPCC reports ourselves and understand what these scenarios mean. Suffice it to say, every scenario leads to a warmer planet, but the scenarios where humans take climate change seriously and work together globally to limit GHG emissions and land degradation are much less disastrous than those where we proceed with business as usual. 

     In A Sand County Almanac, we continue with April floods on the farm and the peace they can bring. Leopold states: "I know of no solitude so secure as one guarded by a spring flood...I see our road dipping gently into the waters, and I conclude (with inner glee but exterior detachment) that the question of traffic, in or out, is for this day at least, debatable only among carp." (p.24) Our narrator then describes the first spring 'flower' -- Draba -- of it he writes that "it subsist on the leavings of unwanted time and space" because it grows so small and in inhospitable conditions. (p.24) Leopold's words have the ability to evoke emotions for even the most minuscule things. All of nature seems to come to life through him. Next, he discusses the changing of the prairie lands through the story of the bur oak. He explains that before settlers came to the prairies and started farming the land, every April fires would run across the land leaving only "scattered veterans, known to the pioneers as 'oak openings,' consisting of bur oaks." (p.25) But, after the settlers plowed the land and stopped the fires, the forest began to grow without hindrance. He quotes John Muir, a native of Wisconsin, as stating: "As soon as the oak openings were settled, and the farmers had prevented running grass-fires, the grubs [roots] grew up into trees and formed tall thickets so dense that it was difficult to walk through them, and every trace of the sunny [oak] 'openings' vanished." (p.28) And, the Wisconsin prairie was changed forever. Leopold concludes his April writings by describing the "sky dance" of the woodcock which he considers great nightly entertainment. 

     Throughout the summer months of May, June, July, and August, Leopold continues to regail us with tails of the sights and sounds of his farm, along with the thoughts that they evoke. While fishing on one June afternoon, he recounts:

I sit in happy meditation on my rock, pondering, while my line dries again, upon the ways of trout and men. How like fish we are: ready, nay eager, to seize upon whatever new thing some wind of circumstance shakes down upon the river of time! And how we rue our haste, finding the gilded morsel to contain a hook. (p.37)

And, though Leopold continues by stating that he thinks eagerness to be a good thing, perhaps it would serve us better to think through our actions a bit more before seizing the world around us. One example of these hasty decisions that might "contain a hook" is discussed in July. The author describes the "prairie birthday" of a small triangle of Silphium plants left behind from the native prairie lands in the corner of a graveyard near his farm. He explains that these sunflower-like plants used to cover the prairie, but now these in the graveyard are "the sole remnant" perhaps in the whole "western half of the country." Evoking a vivid and heart-wrenching scene, Leopold writes: "What a thousand acres of Silphuims looked like when they tickled the bellies of the buffalo is a question never again to be answered, and perhaps not even asked...When I passed the graveyard again on 3 August, the fence had been removed by a road crew, and the Silphuim cut." (p.43) He goes on to explain that most passers by will never notice the end of the Silphuim, as they have not noticed the disappearance of so many other flowers and plants because "[w]e greive only for what we know." (p.46) And, most of us are too busy "seiz[ing] upon whatever new thing" to notice the abundance of life at our feet. 

     In August, we are treated to a beautiful description of what can happen when we slow down and take in the scenery. Leopold recounts "a painting so evanescent that it is seldom seen at all, except by some wandering deer." (p.48) Painted by the river, this painting disappears almost immediately after being 'painted.' He writes: 

To view the painting...visit the bar on some bright morning just after the sun has melted the daybreak fog...The Eleocharis sod, greener than ever, is now spangled with blue mimulus, pink dragon-head, and the milk-white blooms of Sagittaria. Here and there a cardinal flower thrust a red spear skyward. At the head of the bar, purple ironweeds and pale pink joe-pyes stand tall against the wall of willows. And if you have come quietly and humbly, as you should to any spot that can be beautiful only once, you may surprise a fox-red deer, standing knee-high in the garden of his delight. (p.49)

     Next week we will pick up where we've left off in both of these books again.