Freighters are Okay After All
Keywords: greenhouse gas; Derek Paul; cargo ship; Kyoto; jet airplane; hydrogen-oxygen fuel; bunker oil
I’ve been fretting in a public way lately about my inability to determine whether traveling by ship actually emits less greenhouse gas (ghg) than flying. I even got into a bit of an argument by e-mail with a physicist friend, Derek Paul, who thought it was easier than I claimed to find data about the emissions of ships. To my great relief, Derek has answered my questions in a way that I find convincing. He doesn’t have CO2 data but he makes reasonable inferences on other grounds. I feel satisfied enough to go ahead and look for a cargo ship (see photo) going to Europe this spring. From anywhere in Europe it’s easy to take a train to Moscow.
Because I may have aroused anxiety about this subject in some of you dear readers, I will present Derek’s letter here. I hope that it convinces you too, if you’re worried about such matters. (Fortunately, I think I’m actually influencing a few people to cut back on their own fossil fuel-driven travel, so I have a special responsibility to tell the truth.) Here’s Derek’s letter:
Dear Metta,
Thanks for this reply. Far from suggesting that individuals can do nothing, it was I who suggested to you that having families (and you are a family of one) halve their greenhouse gas emissions as a way forward that didn't depend on governments. I said that
a) Shirley and I have roughly halved our ghg emissions these last three years (except for air travel), and we also have now given up air travel), and
b) that if we could persuade two other families to do the same, and if they in turn would each persuade two more families, and so on, there would then develop an exponential in the ghg reductions on the domestic front. In seven years, I estimated, it could have the effect of bringing Canada to within its Kyoto target, only two years behind the specified date, 2012.
It is after 1 a.m., so I am going to answer only one other point in your letter. One really needs to reduce all the kind of information you have come up with to ghg emissions per person per km. If you want to compare transatlantic crossing by air and by ship, you need figures for the total expenditure of fuel and figures for the numbers of passengers carried, as well as information on how those numbers vary with the speeds of travel. You can get incredibly many more people on a QEII than you can on a Boeing 747, and the QEII would be much more economical at 12 knots than at 28. Yes, economical sea travel will always be slow. We need a graph that shows consumption as a function of speed. However, if the QEII is nearly empty, it will use a substantial fraction of the fuel required by a fully loaded QEII. Note my reference to cargo ships earlier. Adding a few passengers makes almost no difference to the fuel expended.
Fuel economy is a steeper function of load for aircraft. A fully loaded jet aircraft requires a great deal of fuel to attain a 10,000m elevation, but from then on its fuel consumption is a matter of speed much more than load. I discussed that a bit in my last email.
The trend in the aircraft industry is to go for larger airbuses, such as can carry 800 passengers. Fitted with hydrogen-burning engines, such craft would produce no carbon dioxide. However, ALL air-burning engines produce oxides of nitrogen -- it has nothing to do with bunker oil, it has to do with the temperature of the combustion. With a hydrogen-oxygen system, engines would be essentially nonpolluting, because there would be no nitrogen, and no carbon dioxide. Burning bunker oil in oxygen would also not produce oxides of nitrogen, of course.
When all is said, however, since sea freight is much cheaper than air freight, it would thus appear that, per km of load, the present slow travel across the oceans easily beats air travel in fuel consumption. Much of the cost of air freight is for fuel, so there must be much less CO2 produced per kg per km across the oceans by slow freighter.
I am glad you are asking friends to make a similar pledge to yours.
Derek
posted by Metta Spencer at 9:57 PM
6 Comments:
May I interject some reason into this anthropogenic discussion on global warming and carbon emissions. Here is an excerpt from junkscience.com:(JunkScience.com spotlights and debunks faulty scientific data and analysis used to promote special agendas,)
While greenhouse is the "what," "global warming" really refers to the "how much." Populist overuse and abuse has largely rendered "global warming" meaningless -- what is really meant is "enhanced greenhouse" -- yes, another term but don't worry, we'll explain this one easily and quickly. Since Arrhenius began speculating a century ago about low CO2 levels and ice ages the hypothesis of temperature relation to atmospheric carbon dioxide has drifted in and out of scientific focus. At present it is the focus of a great deal of attention. "Enhanced greenhouse" means the additional delay in energy loss to space induced by the fraction of carbon dioxide and other greenhouse gases released by humans before those gases are removed from the atmosphere by breakdown and/or biological activity.
So, greenhouse is all about carbon dioxide, right?
Wrong. The most important players on the greenhouse stage are water vapor and clouds. Carbon dioxide has been increased to about 0.038% of the atmosphere (possibly from about 0.028% pre-Industrial Revolution) while water in its various forms ranges from 0% to 4% of the atmosphere and its properties vary by what form it is in and even at what altitude it is found in the atmosphere. In simple terms, however, the bulk of Earth's greenhouse effect is due to water vapor by virtue of its abundance. Water accounts for about 90% of the Earth's greenhouse effect -- perhaps 70% is due to water vapor and about 20% due to clouds (mostly water droplets), some estimates put water as high as 95% of Earth's total greenhouse effect. The remaining portion comes from carbon dioxide, nitrous oxide, methane, ozone and miscellaneous other "minor greenhouse gases." As an example of the relative importance of water it should be noted that changes in the relative humidity on the order of 1.3-4% are equivalent to the effect of doubling CO2.
The adjacent radiation absorption window graphic gives an idea of which molecules absorb various wavelengths. Where the shaded portions completely span between 2 lines it indicates that particular wavelength is fully absorbed and the "window" is saturated (or said to be "closed"). Rather obviously, once a window is saturated adding more gases with the same properties will do nothing. This point seems to cause confusion for some people so perhaps consider multiple shades on a window with each shade blocking half the light coming through - pull one shade and you reduce the light source by half, pull another so you block half the light coming through the first shade, etc.. The effect of each shade diminishes as you keep adding more and eventually you get no additional effect - you have saturated or blocked the radiation window and it makes no difference if you double or quadruple the number of shades again.
Well, I heard that carbon dioxide is bad -- it's pollution, isn't it?
There seem to be a few things that your informant forgot to tell you -- like carbon dioxide being an essential trace gas that underpins the bulk of the global food web. Estimates vary, but somewhere around 15% seems to be the common number cited for the increase in global food crop yields due to aerial fertilization with increased carbon dioxide since 1950. This increase has both helped avoid a Malthusian disaster and preserved or returned enormous tracts of marginal land as wildlife habitat that would otherwise have had to be put under the plow in an attempt to feed the growing global population. Commercial growers deliberately generate CO2 and increase its levels in agricultural greenhouses to between 700ppmv and 1,000ppmv to increase productivity and improve the water efficiency of food crops far beyond those in the somewhat carbon-starved open atmosphere. CO2 feeds the forests, grows more usable lumber in timber lots meaning there is less pressure to cut old growth or push into "natural" wildlife habitat, makes plants more water efficient helping to beat back the encroaching deserts in Africa and Asia and generally increases bio-productivity. If it's "pollution," then it's pollution the natural world exploits extremely well and to great profit. Doesn't sound too bad to us.
But we're responsible for all the carbon dioxide greenhouse effect?
Gracious no! Humans can only claim responsibility, if that's the word, for abut 3.4% of carbon dioxide emitted to the atmosphere annually, the rest of it is all natural (you can see the IPCC representation of the natural carbon cycle and human perturbation here or a simple schematic from Woods Hole here). Half our estimated emissions fail to accumulate in the atmosphere," "disappearing" into sinks as yet undetermined. Humans' total accumulated carbon contribution could account for perhaps 25% of the total non-water greenhouse gases (that is, accounting for all the increase since the Industrial Revolution regardless of source and irrespective of whether warming from any cause might result in an increase in natural emission to atmosphere -- we're simply claiming the lot as anthropogenic or human-caused here).
Here is an interesting newx item:
Greenhouse sceptics to congregate
Katharine Murphy and Brendan Nicholson, Canberra and Richard Baker
February 28, 2007
HARD-CORE global warming sceptics will descend on Canberra today for the release of a book claiming environmentalism is the new religion.
Former mining executive Arvi Parbo will launch Ray Evans' new publication, Nine Facts About Climate Change, at a function at Parliament House.
The book claims climate change is nothing new and declares Howard Government investments in solar power and in cleaning up coal a "complete waste of taxpayers' money".
"Environmentalism has largely superseded Christianity as the religion of the upper classes in Europe and to a lesser extent in the United States," Mr Evans says in the publication.
"It is a form of religious belief which fosters a sense of moral superiority in the believer, but which places no importance on telling the truth," he says.
"The global warming scam has been, arguably, the most extraordinary example of scientific fraud in the postwar period."
The function is organised by the Lavoisier Group, founded in 2000 by Ray Evans and former mining executive Hugh Morgan to test claims that global warming is the result of human activity.
Mr Evans is a longstanding friend and colleague of Mr Morgan and a committed activist on issues such as workplace reform through the HR Nicholls Society, which he founded with federal Treasurer Peter Costello.
Former Labor minister Peter Walsh also will attend today's function, and the group will hold a dinner to be addressed by climate-change sceptic Chris de Freitas, Associate Professor in the School of Geography, Geology and Environmental Science at Auckland University.
Liberal MP Dennis Jensen has organised the function on behalf of the Lavoisier Group and expects about 50 people to attend the dinner.
Dr Jensen, a nuclear physicist, has said he is not convinced that human activity is responsible for global warming.
In an interview with The Age last month, Mr Evans acknowledged that last September's visit by former US vice-president Al Gore to promote his Oscar-winning global-warming documentary An Inconvenient Truth had helped generate a lot of publicity on climate change.
But he described Mr Gore's film as "bullshit from beginning to end".
"The science from the anthropology point of view has collapsed. The carbon-dioxide link is increasingly recognised as irrelevant," Mr Evans said.
"But the Government's frightened.
"Cabinet, from what I understand, is by and large still sceptical of climate change, but it is scared of the drought and worried about how Labor will make use of it
Frankly, Ted, you're full of crap.
Water vapour is indeed the most important greenhouse gas. Its concentration in the atmosphere is thought by most circles today to be a function of temperature. That is, if the global temperature rises, water vapour rises, in a positive feedback loop. That said, many people also believe that it's much more complex than that, as more water vapour means more clouds which in turn act as reflectors of solar radiation. Most climatologists believe that water vapour plays about a 65% role in the total greenhouse effect. However, water vapor has a short life in the atmosphere (about a week) before it condenses into clouds and rain again. Therefore, most climatologists ignore the effect of water vapour as a greenhouse gas that we can control, because we can't.
The entire greenhouse effect is about 33 degrees C. It's the other 35%, the anthropogenic gases that we create, that are the problem. That's why we don't see a 3.3 degree change in temperature with a 10% increase in "greenhouse gases", we see more like a 1 degree change (35% of 10% of 33 degrees). Relative humidity in the atmosphere hasn't changed over the 40 or so years of measurements, and climatologists point out that it never should because of its short life in the atmosphere).
And sure, "natural emissions" from the oceans account for most of the CO2 emissiosn. That's why, up until 150 years ago, CO2 was a constant 300 or so ppm. As we humans started pumping CO2 into the atmosphere, most of that got absorbed by the ocean, yet the concentration of CO2 in the atmosphere increased. Why? Because the carbon sinks in the ocean didn't absorb everything. We are responsible for the 3.4% annually that we emit. The problem is that the 3.4% stays in the atmosphere for about 100 years and represents the proportion that's out of balance. There is no coincidence (and no lack of evidence) that our calculated global CO2 emissions are directly linked to the concentration of CO2 in the atmosphere.
Maybe we'll be lucky. Maybe there's a counteractive effect that we have yet to discover that will counteract our anthropogenic contributions to the atmosphere. Maybe, as the earth warms up, the clouds will act more as a negative feedback and cool the earth, counteracting the greenhouse effect. However, most scientists believe that warmer temperatures will bring more water vapour into the atmosphere (since more water can be held in warmer air) and magnify the effect of warming. It doesn't mean they are right, but I have yet to see any convincing evidence that they are wrong.
There's no harm in reducing our fossil emissions and being efficient with our energy output. It saves money for the consumer. Not relying on other countries and their economies is good for our own. Burning gases creates other pollutants. Being environmentally responsible is the right thing to do.
Do I think we should stop flying and stop driving around because of this? No. Progress has its price. Why should these baby boomers who ruined the world in the first place tell us what to do? But can we do it more efficiently? Certainly we can, if we put our mind into it.
Tim thanks for the compliment! However I am all for efficiency and agree being environmentally responsible is a good thing within reason.
I am concerned about the hysteria and we should listen to Dr. Timothy Ball as well as the pseudo science UN politicians that once again proclaim the sky is falling in order to promote more government and regulations. To quote Dr. Ball:
Global Warming: The Cold, Hard Facts?
By Timothy Ball
Monday, February 5, 2007
Global Warming, as we think we know it, doesn't exist. And I am not the only one trying to make people open up their eyes and see the truth. But few listen, despite the fact that I was one of the first Canadian Ph.Ds. in Climatology and I have an extensive background in climatology, especially the reconstruction of past climates and the impact of climate change on human history and the human condition. Few listen, even though I have a Ph.D, (Doctor of Science) from the University of London, England and was a climatology professor at the University of Winnipeg. For some reason (actually for many), the World is not listening. Here is why...http://www.canadafreepress.com/writers/tim-ball.htm
May I recommend:
Channel 4 Thursday 8 March at 9pm in UK
The film argues that the earth's climate is always changing, and that rapid warmings and coolings took place long before the burning of fossil fuels. It argues that the present single-minded focus on reducing carbon emissions not only may have little impact on climate change, it may also have the unintended consequence of stifling development in the third world, prolonging endemic poverty and disease.
The film features an impressive roll-call of experts, including nine professors – experts in climatology, oceanography, meteorology, environmental science, biogeography and paleoclimatology – from such reputable institutions as MIT, NASA, the International Arctic Research Centre, the Institut Pasteur, the Danish National Space Center and the Universities of London, Ottawa, Jerusalem, Winnipeg, Alabama and Virginia.
HERE IS THE SITE FOR ABOVE BROADCAST:
http://video.google.com/videoplay?docid=-4520665474899458831
Metta,
I've done some research into flying. The effective fuel efficiency for airplanes has changed and I don't like Monbiot's data for airplanes. Maybe it's because I fly them.
I agree with you that if you don't have to fly, you probably shouldn't. However, airplanes aren't the gas guzzlers they used to be.
Part of the reason is because they are more more of the time. Air Canada (and westjet's) passenger loads are close to 80%.
On an Embraeur E90 (Air Canada's newest plane), an average plane carries 75 passengers. Assuming the plane is fully loaded with fuel (16,000 L), the plane has a range of 3,540km. By my math, the plane's fuel efficiency achieves a stunning 99 miles per gallon. There are other factors - every plane carries cargo that is a part of the weight equation. Air carriers are trying to be as fuel efficient as possible.
The Boeing 787 dreamliner will have a per fuel economy of about 120mpg.
So, travel by air (over longer distances) is certainly better than car.
With respect to you travelling on a freighter, you could make the same argument as a plane. Adding a passenger on a plane does not really affect the amount of fuel that the plane carries nor uses. And a freighter is very slow, has no internet, and will be very uncomfortable. In the meantime, while you leave your condo empty, you will undoubtably be using (six weeks, or about 1 ton of C02) greenhouse gases simply keeping stuff in the fridge, having your apartment heated, your clock radio running and using things in the house. So I think it's a wash.
So please, Metta, take a plane. Or better yet, follow your own advice and don't go at all!!! :)
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