Iconic Figure # 1: CO2 trends
Iconic Figure # 1: "Keeling" CO2
In my class I have a set of figures that I call the "iconic figures" of climate change. There are only a handful of them, and they are the figures that I think all of my students should be aware of and understand. One of the exercises that I suggest for my students is to write a figure caption for each of the figures. (Perhaps an extended figure caption.)
Here is the first figure, which has been mentioned by a number of people commenting on recent blogs. This is often known as the "Keeling curve," named for the C. David Keeling who started to take CO2 observations at Mauna Loa in 1958. These data are now taken and maintained by NOAA's Earth Systems Research Laboratory, Global Monitoring Division. This web site is excellent, provides references, as well as access to the observations. Here is a recent update of the Keeling Curve.
Figure 1: Carbon Dioxide at Mauna Loa Observatory.
There are two obvious things in this record. The first is that there is a steady upward trend of CO2. The second is that there is an annual oscillation of CO2. What is not so obvious on this scale is that the amplitude of the annual cycle is increasing. Here is a link to the NOAA site which has much more information on this figure, as well as global averages and numbers of how much the CO2 increases each year.
The steady upward trend is mostly attributed to the release of CO2 by fossil fuel burning. There has been significant effort to account for all of the sources (and sinks) of carbon dioxide, and the increase both correlates with the increased burning of fossil fuels, and it is generally consistent with amounts that are estimated based on fuel consumption.
Some have criticized the use of these particular observations because they are at Mauna Loa, which is a volcano. While this is true, the observatory at Mauna Loa was chosen because, to a very good approximation, it sees clean maritime air. This is constantly checked. One way it is checked is to calculate trajectories to see where the air being sampled comes from. Here is a link to recent trajectory calculations. If there is active volcanism, then is accounted for in the data quality control. It is found, more and more, that the air at Mauna Loa sees emissions and pollution from Asia. This is much more likely than seeing local volcanism.
There has been some significant effort to calculate the CO2 emissions from volcanoes. In the recent time, last 100 years, this amount is estimated to be more than 100 times smaller than that from fossil fuels. Here is the link to the USGS web site on volcanoes. With satellites and other observing systems, there are not any volcanoes in some hidden part of the world that are unknowingly spewing large amounts of CO2 or SO2 or aerosols into the atmosphere. Really.
Back to the Keeling Curve: The annual cycle in the CO2 is caused by the "breathing" of the terrestrial biosphere; that is, plants. Plants use CO2, and when the northern hemisphere blooms in spring and summer, the plants take up CO2. In fall and winter, there is release of biospheric CO2.
Not completely obvious in this figure, but more obvious in stations from high northern latitudes, the amplitude of the annual cycle is increasing. This increase is directly correlated with the "greening" of both North America and Siberia. Because of the warming at higher latitudes, there is greater growth of trees (easily measured by satellites). This greater growth takes up more CO2. On one hand, this increased "breathing" is consistent with the predictions of global warming; hence, it is part of the finger print that contributes to the validation of the theory. On the other hand, some have maintained that the increased biological activity would "take up the extra CO2." There seems to be no evidence to support this assertion, and the observations suggest that increased biological activity cannot keep up - at least on the time scales we have observed.
While it is possible to substantiate that the Mauna Loa station is not, in general, contaminated by local pollution, this substantiation is not generally accepted as adequate. It needs to be validated. One way to do this is to take observations at many other sites. Here is a list of other sites in the carbon observing network. If you were to study the observations from these sites, you would see a consistent signal. CO2 is increasing; there is biological breathing, and the amplitude of the breathing is increasing. However, the amount of CO2 does vary, especially as a function of latitude. This variation reflects a number of items. First, it reflects the enhanced emissions of the industrialized nations. Second, since these stations are located primarily in the northern hemisphere, there is more CO2 in the north than the south. This difference between the hemispheres can be used to estimate how long it takes the two hemispheres to mix.
I will leave it there. Wait for comments, and ask - what are the differences between the northern and southern hemispheres in terms of CO2?
Updated: 10:00 PM GMT on February 03, 2011
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Thanks for the suggestions on the possible content of the WU climate page. Always collecting ideas here - keep them coming.
When I was on sabbatical at Lawrence Livermore National Lab a couple of years ago, I started exploring the delta of the San Joaquin and Sacramento Rivers. This is a fascinating region, especially as it stands in contrast to the San Francisco - Oakland metro areas and Napa and the Central Valley - all of which border the Delta. If you come to the Delta from Vasco Road, north out of Livermore, you curl through part of the huge field of wind turbines that are part of the Altamont Pass. To the west, Mount Diablo bulges from the ground. After you cross the San Joaquin River Bridge, you are driving on top of levees. Many of these levees were built by Chinese laborers after they had built the railways. The towns, which sit below the levees, with the rivers held above, have old Chinatowns and Japantowns.
These levees stand between the salt water of the San Francisco Bay and the interior of California. They hold back the snow melt of the Sierra Nevada, and this is the drinking water for millions; it allows the agriculture of the Central Valley. In the islands of land below the levees there are fields of fruits and nuts, and small towns in varying states of robustness. What struck me first was seeing the elevation of these towns, many miles from the Ocean and the Bay - 11 feet above sea level.
Worrying types like me marvel at the importance and vulnerability of this area. There is so much hydraulic pressure on these levees that fresh water rivers, many miles from the coast, feel two foot tides. This is an area of great earthquake risk. The levees age. The land sinks. Sea level rise of only a few feet increases the pressure on the system. The potential risk of climate change on this area appears, to me, as great as any hurricane risk to Gulf Coast and Atlantic cities.
On a clear day you can see, to the east, the Sierra Nevada across the Central Valley --- The Big Valley, anyone remember The Big Valley? This part of the U.S. has a distinct wet-dry season climate. It is strongly impacted by El Nino. It has rain on the upslope of the mountains and desert in the rain shadows. Historically, the Sierra Nevada Mountains have held a lot of water in snow. That melt is earlier; the Delta has to accommodate greater surges of water. There is water management engineering of every type.
This area is under stress from population and demand. This is irrespective of climate change, but climate change amplifies the stresses. This is the case in many of the impacts of climate change - amplification of existing stresses. This vulnerability to climate change is one of the reasons, very concrete and pragmatic reasons, that California has taken such assertive steps on climate change policy.
Here's a picture from California's Climate Change and Water Resources page.
Here you can see how one state is thinking about the problem.
Updated: 3:23 AM GMT on November 08, 2009
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An Easy Read // A Question for my Readers
An Easy Read // A Question for my Readers
It's been about 6 months that I have been writing this blog. I've enjoyed it, and I have enjoyed the comments. I have tried to write something that is a little bit different than you might see in other blogs. If there is one thing that I want to achieve in this blog, it is not just to argue. To me the split between "believers and skeptics" is old news and in does not feel productive to me. I think it is time to move out of our separate communities, and to start thinking about some of the things we should do and how to do them.
We've talked about the science, and we've talked about the link to issues like population. I have tried to extract some things which seem "true" to me, whether you are a skeptic or a believer. For instance, striving for efficiency and rewarding efficiency makes sense for virtually any rational scenario we might imagine. And if we are going to control the amount of CO2 in the atmosphere in the next few generations, we are going to have to figure out how to remove CO2 from the atmosphere and to sequester the CO2. It is sensible to plan for a warmer world with the sea encroaching onto the interests of people, rich and poor.
Climate change is linked to energy policy and population, and therefore, to national security. Virtually every aspect of society has an interest in and perspectives on climate change. I've written about the billboards that have appeared near Detroit, and I increasingly see the slogan, "What Would Jesus Drive?" This past weekend there were global concerts for climate change. Al Gore has won an Oscar. The IPCC has (and is) releasing definitive reports. It seems like we are at a transition point. Or a bubble.
On reason I wanted to write a blog at WU is that a cross section of society comes to WU for weather information. (Of course, only a small percent make it to the blogs, and then they are drawn to the allure and controversy of the MasterBlog!) Still, it is not a group of readers who have necessarily placed themselves into one camp or another. It is a group of people who can contribute valuable ideas to the way forward, to help separate the important from the unimportant. I have this idea of developing something like an open source or Wiki climate community--doing some science maybe, developing a WU "what should we do" community.
Here we sit. At WU we are thinking of going from a Climate Change Blog to a whole climate page. What you would like to see on such a page? What sort of information, analysis, opinion, or community participation would bring you there?
Figure 1: A figure from my class. The scientific investigation of climate change is communicated through many channels. People take in these communications, and some accept the science, some reject it, and some let it tumble and roll. This impacts many external communities, and it also impacts future scientific investigation. Ultimately, there are consequences that impact the foundation of society and civilization. What pieces need to be added to this figure?
MORE FROM THE DISCUSSION
From fredwx: "What is the relative contribution of CO2 to the greenhouse effect given it constitutes less than 0.04% of the atmosphere? How do we know this?"
Is the question here how can something so small have such a large effect?
I think there are two things to remember. 1) The additional "heat" of global warming is, itself, a small effect. (That is why it is so easy to argue about.) The "natural" water and CO2 keep the Earth at say approximately 290 degrees Kelvin (absolute). So we are talking about say 2-3 degrees on top of this ... so, that is a 1% change in temperature. I don't know of anyone who argues that the "natural water and CO2" are not responsible for maintaining the Earth at its habitable temperature. So if you think about adding substantially to the natural CO2, then an incremental warming of 1% does not defy expectations. Does this make sense?
2) We have many examples of where something small has a big effect. One of the best analogies to greenhouse warming is the idea of a blanket. One could argue, how does say a 2 pound blanket have a chance of keeping a 200 pound man warm. It is because the physical mechanism that is important is not first and foremost dependent upon mass. In fact, you could find an even lighter insulator ("the space blanket") that would hold the body's heat more effectively. But ... there are many instances of small amounts of stuff have very big effects ... DDT and bird's eggs, sewage in drinking water, etc.
As for how do we know ? ... We make excruciating calculations that are compared with both observations and theory. We compare piece by piece and see if we can calculate the energy balance. This is a fundamental practice in physics, and it is a matter of belief whether or not one accepts the robustness of knowledge generated and validated in this way.
I am trying to understand the foundation for your comment argument ... I hear it often.
ZRR: Thanks for the comments. I don't intent to shut down debate. I think that productive debate is part of moving on. Part of this is recognizing the substance of the points of view in the debate. One of the important things will then be to determine which points of the debate are consequential for action, and which are not.
There is a certain type of argument, and I am not a student of rhetoric, which diminishes arguments because they, what, question the intent, call each other names, hijack the flow of the discussion with emotional stabs ...
Since I believe that those who are not "devoted" to global warming have a substantive stake in the future, I want this to be a place that is of interest to the "undevoted."
NRAamy ... agree on ethics. I bring in ethics lectures early in my class. It usually comes in the realm of "winners and losers."
Many of you ... I think it is true in virtually all undertakings that the zealots become their own worse enemy. One of my goals is to look beyond that. This bubble will burst, then the real work begins. That's just part of the process ... the it's fashionable, your own worse enemy stage.
SOME SUMMARY COMMENTS FROM THE DISCUSSION
Here's a list.
From my entry I am going to start a list.
Things that we should do no matter what.
I will add from the discussion ....
Coastal Restoration and Management
Others .... ????
I also ask two questions.
What are the weaknesses in "the science" of greenhouse gas warming? I mean the basic science of warming by greenhouse gases?
If you do not accept the attribution of warming in the past century to mankind and fossil fuel burning, then does that mean that we should do nothing about the warming?
Updated: 3:38 AM GMT on November 08, 2009
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Dust, Snow, and Water
Dust, Snow, and Water.
My last blog on population and land use was partially motivated by a recent paper in Geophysical Research Letters on the role of dust in accelerating snow melt in the Colorado mountains. The article is by Thomas Painter and co-authors, and here is a link to the abstract . The gist of the article is that dust landing on the snow can accelerate the melting of snow and reduce the annual snow cover duration by 18 to 35 days. This is a detailed study of the San Juan Mountains.
The source of the dust is convincingly linked to the Southwest U.S. and is related to the expansion of grazing, recreation, and agriculture. This is, of course, first and foremost a decision of land use, which is related to population pressure on the land. There are similar examples around the world, and the water supply of more than 1 billion people is directly linked to mountain snow packs.
The investigation by Painter and co-authors is the type of investigation that often gets wrapped up into the whole discussion on climate change. A warming globe would accelerate the spring snow melt. If you are predisposed to argue, this could evolve into climate change versus farm dust. In the spirit of scientific investigation, this becomes a course of study--how do you separate the potential climate change signal from the dust signal? (I'd be glad to hear reader proposals.)
Some of the responders to the last blog brought up the work of Jared Diamond . His two books Collapse and Guns, Germs, and Steel are provocative studies of how humans have evolved with their environment.
I want to try to combine the ideas from the paragraphs above. We are faced with many choices. We can use Diamond's work to show that what happens to us is, at least at times, related to the decisions of how we value our environment. We can use the work of Painter to see that if we were to change our practices of plowing and recreation and grazing, we could impact the stability of the water supply for billions of people. This might not stop climate change, but it would help us adapt--it would keep us from, essentially, accelerating the impacts of climate change. (It also opens up other paths for adaptation.)
It would be in the spirit of some of my readers, and perhaps me at times, to say that the pressure of population will ultimately overwhelm any efforts of adaptation. NPR is running a series called Climate Connections, and a recent entry was on the return to trees in Niger. Niger is one of places which suffers from severe desertification. The return of the trees can be directly linked to planting and the development of practices that allow the trees to grow.
We can make a difference. Again, we can argue over detection and attribution. We can argue about the economics of it all. We can recognize the role of population and standard of living. We can look at the past and decide that we are doomed. Or we can look at the past, and the fact that we have useful predictions for the future,meaningful ways of adaptation and mitigation, and decide that we can do something about it all.
Stabilizing Sand dunes: From United Nations Convention to Combat Desertification
Updated: 4:59 AM GMT on November 08, 2009
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Population, Land-Use and All That
Population, Land-Use, and All That
I have moved the blog discussion towards population, maybe more than I should, but with some purpose. If you go back and look at the comments peppered among the entries, there are many comments that climate change is not the primary problem. There are also other comments that many of the things that are casually attributed to climate change are, first and foremost, more closely related to the things we do, like build million dollar houses on barrier islands.
As many of you know, Roger Pielke Jr. has written extensively on hurricanes and global warming . In the 2005 paper, linked above, Pielke and his co-authors examine the attribution of increased damage from recent hurricanes to global warming. I know some people who have used this paper to discredit the science of global warming. If you read this paper, it does not challenge the science of global warming. The paper draws the conclusions that it is "premature" to conclude that the impact of recent hurricanes can be connected to global warming. In the end, Pielke makes the argument that premature attribution of cause and effect allows, essentially political, attack on the scientific foundation of climate change. It keeps policy from forming.
Population increase, consumption, migration to the coast, deforestation of mountain slopes all exist in the same world as climate change exists. I used to try to organize all of these pieces in something like a flowchart or a circuit diagram. More recently, I am drawn to something that is more of a "biological" model; that is, for example, population demand on resources and climate change both exist. They are related to each other. Sometimes that relationship is clear and strong, sometimes it is more subtle. The relationship changes with time --- like organisms. There is some value in recognizing the complexity of the relationships, and that they change with time.
For example, it is clear that much of the destruction of New Orleans by Katrina is related to a series of land-use and disaster preparedness decisions that were simply not adequate. New Orleans has been in a vulnerable location from the beginning, and its vulnerability increased over the decades for many reasons. The real role of climate change will be to increase New Orleans' vulnerability in the future. (What do you think about "rebuilding New Orleans?")
It is important to separate the climate change issues from other related issues such as land-use. It allows for the development of more robust strategies for adaptation and mitigation. It makes the problem of climate change more tractable; it removes some of the points that perpetuate nonproductive arguments.
Returning to the issue of population and consumption--so far in all of the discussion of climate change and responses to future of climate change, there is the sacred notion that the economy needs to continue to grow. The United States sets economic growth as a criterion of its culture. Other nations set similar requirements for robust economies, plus lay a claim to develop improved standards of living. If you require economic growth, if you require the use of energy for economic growth, if you connect energy use with standard of living, if you rely on burning ancient stored carbon-based fuels, then economic growth requires, today and tomorrow, increased emissions of carbon dioxide. (This leads me to one of my small number of conclusions--we will have to figure out how to sequester carbon dioxide.) So, yes, climate change is a problem of population and economic growth, and we as a species seem to claim both of these as inalienable rights. The fact that climate change is a problem of population and economic growth does not make it a less real problem. We are not allowed to dismiss the consequences; we are not allowed to reject the knowledge that we have.
Prometheus Science Policy Blog .
Updated: 6:56 PM GMT on March 12, 2008
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