Tag Archive: carbon dioxide


Watts Up With That is a very, very silly website.

Here’s what I mean: In a recent article at WUWT, chemical engineering graduate Steve Burnette tries to dismiss concerns about ocean acidification, but his claims are outright wrong when they are coherent. The centerpiece of the article is a calculation meant to estimate the change in ocean pH over the 20th century. Unfortunately, it’s been badly bungled.

First, let’s go over a few preliminaries.

The carbon dioxide system

Figure 1: The carbonic acid equilibrium system. Atmospheric CO2 is in equilibrium with dissolved CO2, which in turn is in equilibrium with carbonic acid. The acid has a tendency to lose its hydrogen ions, forming bicarbonate ion, which it is also in equilibrium with. The bicarbonate can also lose a hydrogen ion, forming carbonate. Keep in mind that these steps work in reverse; in particular, carbonate ions can react with hydrogen ions to form bicarbonate.

When fossil fuels are burned, about a third of the resulting carbon dioxide ends up dissolved in the oceans. There, it undergoes a series of reactions, first combining with water to form carbonic acid, then losing protons one at a time. The result is a mixture of dissolved CO2, bicarbonate, and carbonate ions, as well as an increase in hydrogen ions, which increase the acidity of the seawater.

Burnette mentions a few principles which are useful for analyzing this scenario. The equilibration between gaseous CO2 and dissolved CO2 is expressed by Henry’s law, which states that the concentration of dissolved CO2 is proportional to the partial pressure of atmospheric CO2. This means that, as CO2 concentrations increase in the air, they will increase in the oceans too. Mathematically: Continue reading

I had thought that once I graduated college, annoying student publications would quit being so… annoying. Alas, this isn’t the case. A previous article examined the quality of analysis at the Carolina Review, UNC’s ‘journal of conservative thought and opinion'; let’s see if things have approved any in the handful of years that I’ve been away.

Okay, checking their blog… mhmm… skim the headlines, clickety clicky….

… oh sweet cthulu, rise from your watery slumber and please make it stop.

The linked article describes environmentalism as factually challenged and lacking a vision of “the overall big picture”; let us categorically examine the main evidence presented in support of this thesis:

  1. “global warming, or climate change, or whatever they feel like calling it now” has been grossly exaggerated.
  2. Lighter cars are inherently more dangerous than gas-guzzlers.
  3. Recycling is bad.
  4. Fossil fuels can be greenwashed.

Ready? Let’s go.

Why is [head of NASA’s GISS program and accomplished geophysicist Dr. James] Hanson [sic] so important?” – Carolina Review columnist Alex Thomas

I was disappointed by the coverage of climate change. I expected it to be lousy, and it was, but I didn’t expect it to be so… unsatisfying. The only evidence presented is the claim that Dr. Hansen’s 1988 congressional testimony was critically flawed, greatly overestimating the amount of temperature change to come. This is a PRATT, a Point Refuted A Thousand Times, so my treatment will be a bit superficial.  (For more detail, read this)

Some of Hansen’s scenarios gave realistic predictions, and some didn’t. The real question is why.

A climate simulation isn’t a magickal box that spits out numbers. In order to run it, you have to input certain parameters, like how bright the sun is, the greenhouse gas concentrations, and so on. For the past you might have direct measurements or proxy records; the future is not only unwritten, but contingent upon human agency. So you have to come up with plausible scenarios for what’s coming. Maybe we cut down on fossil fuel usage; maybe we ramp it up; maybe we relax clean air standards; maybe we have a nuclear war. You run the scenarios you’re interested in on climate models, and you compare, contrast, and interpret the output. One of the scenarios that Dr. Hansen used (“Scenario A”) overestimated greenhouse gas emissions – but not carbon dioxide. Scenario A assumed that we continued to emit CFCs, which are potent greenhouse gasses. Because they threatened the ozone layer, CFCs were phased out under the Montreal Protocols, which went into effect in 1989 – the year after Hansen’s testimony. Nowhere in the Carolina Review article do we hear about such confounding factors, nor the general success of government regulation in cutting down on ozone depletors. Nor is there mention that Scenarios B and C match observations well (see above), nor that Hansen’s 1981 predictions were freakinshly accurate. * Also, why is Dr. Hansen important? Because he was an adviser to Al Gore, of course!

Usually investigators only present and discuss the risk to occupants of the car or truck in question—as if society at large has no stake in the mayhem caused by some vehicles as long as those riding in them aren’t themselves killed.” – Wenzel and Ross 2008

Continue reading

I sit at the Carrboro Really Free Market, on the first caturday in July. I sit in the shade and the banners are blowing lazily in the breeze; still it’s nearly 100 degrees; the humidity jacks it up to 103, and the breeze is welcome but ineffectual. Air quality is ‘Orange’: ozone levels ‘may approach or exceed unhealthy standards.’ A parade is planned but only a handful want to move; I’m definitely not going back out. I keep a cold pack in my bag to refridgerate my computer, but I worry that the condensation from the humid air will offset the benefits of a cool processor. Whatever; I need chill tunes if I’m going to bike around in this weather.

A constant source of frustration for me is communicating the local importance of global problems. Climate change is real, and it’s serious – but at the same time it can be intangible and diffuse. I live in the North Carolina piedmont, hours away from the beach. I can explain to my neighbors that ocean acidification is a serious problem, that the demise of coral reefs would mean the loss of food and resources for the third world. But even if they believe me, even if they agree that it’s bad news, it can still be hard to see how global warming effects them personally, as a homeowner, a farmer, a pet owner or the parent of a young child, a worker with a daily commute. How does carbon dioxide pollution impact North Carolina and beyond?

rock me momma like the wind and the rain//rock me momma like a hurricane

Let’s start at the beach. An obvious problem here is rising sea levels. As the ocean heats up, it expands; as ice heats up, it melts and drains into the sea (or, it calves, falls into the sea, and then melts). This causes a slow but steady rise in sea level. Sea level is predicted to rise by a meter (maybe more) over the 21st century, and 4-6 m over the next few centuries. This is bad news bears – in many coastal counties, more than 10% of the population lives within a meter of high tide. The threat to homes and businesses is worsened by storm surges, which will also be higher as the seas rise [Strauss 2012]. North Carolina has a unique relationship with sea level rise. The coastal salt marshes have recorded 2,100 years of sea level history in their smelly mucky sediments; the ocean stayed relatively stable up until about 1880, when it began to creep upwards. The average rate of sea level rise for the NC coast over the 20th century was ‘greater than any other persistent, century-scale trend’ in the marsh’s memory. During this time period, the seas rose 3.5 times faster than they did even during the Medieval Warm Period, and regional sea level rose faster than model predictions over the 20th century (though the uncertainties involved overlap.) [Kemp et al. 2011]

Sea level rise at the North Carolina coast over the past two millenia. Things are pretty stable, even during climatic episodes like the MWP – until we get to the late 19th century. Then the hockey stick gets hockey stuck. GIA is glacial isostatic adustment, an additional factor which must be considered. It deals with the fact that the North American landmass is still rebounding from the weight of Ice Age glaciers. Image from Figure 2 of Kemp et al. 2011

But what’s really special is the state legislature’s reaction to the rising tide. This June, the NC Senate infamously outlawed the use of accelerating sea level scenarios in planning urban development. The usual astroturfing seems to be at play: the money trail for this legislation leads back to the Locke Foundation; spokespeople and nonprofits proliferate to establish a consent factory. These hijinks are as cynical as they are asinine: not only is global sea level rise accelerating [Church & White 2006], but North Carolina is at the southern end of a ‘hotspot’ where the sea is rising 3-4 times as fast as the global average, [Sallenger et al. 2012] putting its coastline at exceptional risk. The legislation is also a lovely inversion on a popular skuptik trope, that of an authoritarian scientific Orthodoxy dictating Truth and squelching dissidents. In this case, it’s the state government which has declared which climatic scenarios are kosher and which are thought crimes, favoring the least alarming. The proposed law would not merely declare what course sea level rise will take in the years to come, but also prohibit state planning agencies from considering alternatives. Not content to legislate straight marriage as the only valid relationship, the Old North State is considering straight lines as the only acceptable graph.

“You need to move indoors right now.”

Meteorologist Dr. Forbes, on Philadelphian extreme weather.

It’s Friday night, 29 June, and forecasts of a sweltering weekend have already started to come true. I am sifting through hardware at work when the power goes out. Continue reading

A while back, we started looking at a poorly thought-out article from the website C3Headlines. C3 is starting to make a name for itself as a goldmine of climate comedy- their claims have recently been addressed at Tamino and SkepticalScience.

We’re going to keep digging into C3‘s claim that carbon dioxide concentrations have been increasing linearly over the 20th century. They seemed to draw this claim by eyeballing the graph of CO2 concentrations and qualitatively describing them as linear, apparently using the inset in their first figure to compare linear, quadratic, and exponential trends. This is a faulty method: it’s an elementary fact of calculus that ANY smooth curve, when viewed appropriately, will appear linear. The point has already been made but it’s worthwhile to keep looking because there are some interesting graphical follies at play; examining them further might help us understand how and why graphs are misunderstood.

Figure 1: From C3Headlines’ article on “The Left/Liberal Bizarro Anti-Science Hyperbole”, which claims that CO2 concentrations are increasing linearly. Click to read it, if you dare…

C3‘s second graph in this article measures the change in atmospheric CO2 by calculating a month-to-month percentage change. It’s not entirely clear why they are using a percent change, rather than the standard practice of expressing rate of change as concentration change per year (like the source of their data uses). Whereas ppm/year is an absolute measure, each datum generated by the percentage-change method depends strongly upon the value of the previous month. As a measure of long-term rate of change, it is a bit questionable.

My primary concern, though, is with their use of monthly data in the first place. In my last article, we noted that, without explanation, C3 confined their focus to January CO2 concentrations. Were they consistent, they’d also look at January rates of change – of course, doing so might lead to unacceptable conclusions.

 Figure 2. Rates of CO2 accumulation have been calculated for the month of January, consistent with earlier investigation of January CO2 concentration. Over the period of observation, rates have increased at a significant (P~0.0005) acceleration of 0.11 ppm/year^2. Monthly rates throughout this article have been calculated by considering the change in CO2 between adjacent months, and assuming that a month is 1/12 of a year. Interpolated values of CO2 were used to avoid annoying data holes early in the record.

Instead, they look at the rate of change for every single month on record. Why do I find that problematic? Well, let’s look at the full record, with monthly resolution: Continue reading

I love graphs – my eyes quickly glaze over at a table of numeric data, but a graph, used correctly, can quickly and easily tell the whole story.

‘Used correctly’ is the key phrase – for all their power, graphs are infamously easy to bungle, and when used incorrectly they can misinform – or lie outright.

I’m going to look at an example that touches on a few graphical and statistical concepts near and dear to my heart, as well as carbon geochemistry.

Fig. 1: An image from C3Headlines; the 3 C's are "Climate, Conservative, Consumer". Oh, and the article is titled "The Left/Liberal Bizarro, Anti-Science Hyperbole Continues". It sure would be tragic if they made obvious n00b mistakes after using such language. Click for link!

Coming from an article on the website C3Headlines, this image claims that carbon dioxide concentrations have ‘Linear, Not Exponential Growth’. thereby ‘expos[ing] the lunacy of typical left/liberal/progressive/Democrat anti-science’, The author has reached this conclusion by graphing January CO2 levels* and fitting a linear trendline to them.

Already this is a warning sign – the comparisons the author makes are entirely qualitative, apparently  based up on eyeballing the graph. However, trend lines are created by a statistical process called a linear regression, which comes with a caveat: it will fit a trend line to ANY data given to it, linear or nonlinear. Fortunately, there are also ways of evaluating how good a trend line is. Continue reading

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