I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.
By: RickyRood, 06:39 AM GMT on aprilie 25, 2012
Rhetoric Again - Cycles:
A few entries ago I wrote about the form of argument and the rhetoric used by those who advocate that the science of climate change is flawed in some fundamental and philosophical way (also here). In that piece I made reference to long-reaching metaphors and isolated facts that are used to create doubt about climate science. These metaphors and facts, for example that there was a lot of carbon dioxide when there were dinosaurs, create a stop or a pause in the conversation and pose as seeming contradictions and serve as distractions to make logically flawed points. For those who want to hone up on your arguments, I find the Marshall Institute’s Cocktail Party Guide to Global Warming some of the better coaching of anti-climate-science rhetoric.
I have been thinking about one of the common statements that is made, and that is the one about their being a lot of carbon dioxide when there were dinosaurs and, more generally, that there is a long record of cycles between times of high and low carbon dioxide in the Earth’s atmosphere. This has been presented to me many times, and I often wonder, what exactly is the point that is being made?
At first, when I heard statements that there was very high carbon dioxide in the past, it seemed to be with the implication that this was one, a natural occurrence and two, a fact that was being hidden by climate scientists. True, it is a natural occurrence. Any comprehensive text book on climate change will discuss the past variations in carbon dioxide and that there have been times when carbon dioxide was much higher, and the Earth was much warmer. It is not hidden, rather it is used to inform our future.
Following from the introduction into the argument that the high values of carbon dioxide in the past were a natural occurrence, there seemed to be two points. First, was that very high values of carbon dioxide were possible in the absence of human-responsible emissions and second, that changes in carbon dioxide amounts were beyond our control and hence there was little sensibility in reducing our emissions. There is the further implication that since this is natural then it is OK.
Our real concern about climate change is that climate change impacts humans. If it were not for the impact on humans, climate change would be a curious problem of natural science. When there was a lot of carbon dioxide and dinosaurs, there were no humans. That does not mean that with high carbon dioxide that humans can’t survive and that dinosaurs will return. However, getting from the stable temperate climate in which our civilizations evolved to a climate where the temperatures are several degrees warmer will be a disruptive path. There will be less land as sea level rises, and since there is a huge concentration along the coasts of the world, there will be huge relocation of people, disruption to nations, and loss of infrastructure. There will be enormous changes in ecosystems and domestic plants and animals.
So yes, there are cycles and there has been a lot more carbon dioxide in the air, but that has been in the absence of billions of humans, our built environment, and our fragile balances of nations and economies. It is the disruption of the fragile balances of human enterprise where the risk lies – so how does the fact that carbon dioxide was high when there were dinosaurs bear on the current concerns about increasing carbon dioxide and global warming?
Carbon dioxide was high in the distant path – does this suggest that carbon dioxide amounts in the atmosphere are beyond our control? Why was carbon dioxide high? Is that simply an unknowable mystery?
The composition of our atmosphere is determined by many factors. In the long term, my geologist friends always remind me that the composition of the atmosphere is determined by geology and the cycling of gases between the atmosphere and ocean and the solid Earth. This long time frame, millions or billions of years, is not exactly relevant to our human experience. On a shorter amount of time, like the ice age cycles, or the large amounts of carbon dioxide when the dinosaurs were present, biological processes are important for determining the composition of the atmosphere. We have benefitted from many millions of years when carbon dioxide and oxygen existed in a balance that support plants and animals. Those cycles, those extended periods of high carbon dioxide, are characterized by changes in balance of plant and animal life. They are characterized by the ocean taking up and giving back large amounts of carbon dioxide to the atmosphere through both chemical and biological processes.
So are we destined to simply be at the fate of these major shifts? Are these shifts beyond our control? Aren’t they natural?
Let’s get back to humans. There is little doubt that humans are the dominant life form on the planet today. We shape every ecosystem. We consume all forms of energy. Like the balances between plants and animals in the past we change the atmosphere and the ocean. Not only are we a dominant life form, we have this amazing ability to extract rocks and liquids and gas from the Earth and burn it. We have the ability to push around land, to make concrete, to remove mountains, and build islands. We are, therefore, not only biological, we are geological.
We are part of the cycle. We don’t simply exist at the mercy of the cycle.
So what is the point of a far reaching reference to the time of the dinosaurs and high amounts of carbon dioxide? Perhaps the point is to take us out of the equation, to absolve us of our responsibility to the planet, to allow us to do that which we want to do.
In the end this takes us to some very basic questions about humans and knowledge. I recently saw an idea attributed to Tim Flannery (also here), that humans are a species prone to destroying their future by destroying ecosystems. As I understand the argument, because of our intellect, we can continue to extract from the Earth resources beyond which a less creative species would be limited by brutal, natural barriers. We can rapidly cause extinctions. So far we can find and perhaps nurture new resources as we destroy the old.
We have this unique capacity of knowledge. We can place ourselves into our environment and see ourselves as shaping our environment, and have responsibility for maintaining our environment. We are not, entirely, at the fate of nature, or cycles, but we are part of nature, of cycles. And as such we might not be able to determine our future, but we are able to influence our future. We don’t have to be destined to destroy our future.
Scientifically, the statement of facts about cycles and high carbon dioxide millions of years ago has little bearing on whether or not we are burning fossil fuels, increasing carbon dioxide and warming the planet. Such presented facts are a diversionary part of a belief-based and politically based argument. Some advocates of the politically based arguments are trying to stop a societal response to carbon dioxide emissions. Other advocates are making a basic belief based argument that humans are somehow outside of biology and geology of the planet as a whole; that we are not just another age of some dominant life form. To me, what makes humans different is we have this ability to accumulate science-based knowledge, which is actionable, which imbues responsibility, which allows us to be different, and to sustain our future.
Updated: 11:29 AM GMT on iulie 02, 2012
By: RickyRood, 03:33 AM GMT on aprilie 11, 2012
A Hot Day’s Night: The Beetles -
The semester is almost over here in Michigan, and I am looking forward to more regularity in writing these blogs. Sorry for the recent infrequency, and the occasional excursions into the arcane. I am looking for well posed, interesting, new questions to focus on, and you know how to find me if you have a good idea. In this entry I want to build of the recent heat and the early spring.
The thread I made through the last blog ended up with Plant Hardiness Zones, which are those maps that gardeners and farmers use to decide when to plant seeds. Over the last 20 – 30 years the warming of the planet has caused the northern migration of these zones. The Washington Post has an excellent graphic that shows the changes between 1990 and 2012. Since I am not so facile, I have taken from this graphic the two extremes, 1990 and 2012.
Figure 1: 1990 U.S. Plant Hardiness Zones. (From Washington Post)
Figure 2: 2012 U.S. Plant Hardiness Zones. (From Washington Post)
What I want to look at here are the very coldest temperatures, the purples. If you look at Zone 2b, the zone below -40 degrees F, it essentially disappears between 1990 and 2012. Zone 3a, which is between -35 degrees F and – 40 degrees F becomes much smaller.
So this past winter, and especially March 2012, was extraordinarily warm in the 48 contiguous states. In fact, I, who fly too much, had one of the easiest winters of travel. Based on Jeff Master’s blogs, I chose several times to go through Chicago, and for the most part I have landed with splendid views of a blue Lake Michigan. There was an interesting piece on Talk of the Nation, noting the relation between a warm winter and the lack of flu. So what is the problem? It’s not below -40 degrees anymore. Air travel is easier. We might have less flu. Does anyone besides me, planting potatoes on a dry 80 degree day in March, worry about this?
I have been spending a lot of time with beetle-killed wood this year. You might recall a couple of blogs back in 2009 where I talked about the pine beetles which are killing millions of acres of pine trees in the western U.S. and Canada. (Climate Change and the Forest, Climate and the Beetle) It is beautiful wood, often with a light blue tint. I am using it to restore a couple of 100 year old out buildings. There is a LOT of it; in fact, more than one can imagine managing. There is some lumber being made, some fire wood being made, but for the most part there are millions of acres of dead trees. I have talked to a couple of people who wonder why there is not more outrage about these massive forest kills. That’s fodder for the comments.
Back up to the maps. The pine beetle responsible for killing the pines in the Rockies is itself killed, controlled, by temperatures less the -40 degrees F. This is at the edge of the coldest temperatures normally seen in the U.S., and these cold extremes have largely disappeared since 1990. In the map below, I have used the interactive version of the map from the US Department of Agriculture to extract the State of Colorado. There are only very small areas of Zone 3a remaining.
Figure 3: Plant hardiness zones in Colorado for 2012. From US Department of Agriculture.
We adapt to climate change – or we will. Now, one of the most effective adapters seems to be the Mountain Pine Beetle. In The American Naturalist there is a pre-publication posting of an article on the Unprecedented Summer Generation of the Mountain Pine Beetle. That is, rather than there being one generation of Mountain Pine Beetle during the year, in Colorado, in recent years there have been two broods. The paper is by Mitton and Ferrenberg. There is a press release of the paper here.
They noted in 2008 pine beetles flying and attacking pines more than a month earlier than the historic norm. They set up experiments to test three hypotheses: 1) That temperature had not changed; 2) That the length and timing of the flight season had not changed; and 3) the life cycle of the beetle had not changed. Their results found that there had been significant warming, with spring coming earlier. They found that the behavior of the pine beetle was explained by earlier emergence of the beetles, followed by a second brood of the beetles in the summer. Figure 4 shows this schematically. It is striking to see the move to earlier springs in the figure – as with the hardiness zones.
Figure 4: The historical mountain pine beetle (MPB) univoltine life cycle (above calendar arrows and linked by black arrows) and the observed MPB bivoltine life cycle (below calendar arrows and linked by red arrows). Univoltine means one brood per year, and bivoltine means two broods per year. Calendar arrow colors represent monthly temperature regimes: blue for <0°C, yellow for 0°–4.99°C, orange for 5°–9.99°C, and red for 10°C and higher. From Mitton and Ferrenberg, Mountain Pine Beetle Develops an Unprecedented Summer Generation in Response to Climate Warming.
This research took place in an area that in the 1970s was judged to be “climatically unsuitable for Mountain Pine Beetle development … .” The study is convincing that the devastation of the forest due to the pine beetle is directly related to the warming planet. It points out the vulnerability of the tree populations, as the trees that are being impacted now have not developed a historical resistance to the pine beetle. Since most of the beetles that are born live, this impact is not incremental, as that second generation is enormous.
So, yes, this warm winter has had its advantages - less fuel oil was needed. But in the western forest we are seeing this case study of wide ranging ecological disruption. The consequences of the disruption will unfold in the next decades. Questions of fire and soil erosion will emerge. The impact on tourism will be realized - and, of course, water quality and the change in the ecosystems of the western forests. The Mountain Pine Beetle is adapting rapidly to global warming, what are our strategies to adapt to the Pine Beetle?
Updated: 08:02 PM GMT on mai 21, 2012
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