Humans are Causing Global Warming 1342
Big_Al_B writes "A Times Online article discusses a new study comparing 7 million real world datapoints with several computer models of global warming. Each model had a possible cause associated with it." From the article: "It found that natural variation in the Earth's climate, or changes in solar activity or volcanic eruptions, which have been suggested as alternative explanations for rising temperatures, could not explain the data collected in the real world. "
No shit sherlock? (Score:1, Informative)
The requested URL (science/05/02/18/1558239.shtml?tid=146&tid=14) was not found.
If you feel like it, mail the url, and where ya came from to pater@slashdot.org.
Old news (Score:5, Informative)
The science behind global warming (essay) (Score:3, Informative)
Interesting speech by Michael Crichton on whether global warming is science or politics and what the difference is. Highly recommended no matter what side you are on.
Of course, who wants to be on the side of ignoring or supporting the widespread destruction of the planet by humans? Therein likes the rub...
Re:An idea (Score:5, Informative)
No, it just shows that you know how to use Google.
i) The propagation mechanism for Rossby Waves [soton.ac.uk]
ii) The primary sources of deep water formation in the Atlantic [usc.edu]
iii) How a western boundary current is formed [iugg.org]
iv) What Meddies are. [xs4all.nl]
v) What a pycnocline is. [noaa.gov]
Re:And... (Score:5, Informative)
In 2001, President Bush "withdrew" the US signature on the Kyoto treaty -- I have no idea if such a withdrawal is legitimate, not that it matters much.
Re:Accurate weather simulations?? (Score:5, Informative)
An analogy would be that if you flipped a coin once, you wouldn't be able to tell if it would end up heads or tails, but if you flipped it a thousand or a million times, you'd notice a general trend of 50-50.
climatologists unite! (Score:2, Informative)
Re:Indeed... (Score:3, Informative)
Do you have any knowledge of statistical models? (I'm not asking to be a jerk, I'm just wondering). Basically if you have data subject to seasonal variation, you'll need multiple periods' worth of data to correct for this. As far as climate goes, its period is similar to geologic timescales, or in other words, thousands and thousands of years. We don't have thousands and thousands of years of climate data, let alone multiple periods' worth. That makes modeling changes fairly difficult, because you don't know if what you're seeing is just part of the seasonal effects or not. Please note that I'm not using the word "Seasonal" to mean spring, summer, fall and winter here. Seasonal refers to the natural periodic varation that occurs in the data. That's why the person who made this comment says the model may not be accurate.
Re:Indeed... (Score:5, Informative)
Reaction is Premature (Score:3, Informative)
There will be plenty of time to work one's self into a lather once the article has been reviewed.
The actual studies (Score:3, Informative)
BBC coverage here [bbc.co.uk], probably a bit more detail than the Times. No, I haven't RTFA, it's just a gut reaction based on 20 years' exposure to the rotting carcase of a once-great newspaper, rotten with the maggots of the parasitical MurdochWasp that impregnated it with it's eggs... (yep, I don't like Rupe, does it show? :)
Re:And... (Score:3, Informative)
Re:The science behind global warming (essay) (Score:5, Informative)
Also worth reading is their original article examining the science in State of Fear [realclimate.org].
Re:Flame Away! (Score:3, Informative)
Hubris (Score:2, Informative)
"In the study, Dr Barnett's team examined more than seven million observations of temperature, salinity and other variables in the world's oceans, collected by the US National Oceanic and Atmospheric Administration, and compared the patterns with those that are predicted by computer models of various potential causes of climate change."
Let me get this straight: The group assumed that certain factors were relevant to global energy input, output and flux, that the measurements of these factors were both accurate and comprehensive, and that, most importantly, because THEIR OWN MODELS said that these other factors did not a significant impact, that only anthropogenic CO2 emissions could be the cause of the modeled behavior?
As a graduate student in the 90s I built much simplifer models (geographically) that sought to replicate and predict groundwater transport and the evolution of jet fuel spills at airports. One of the fundamental tenants of such models is that the output depends on both the input data provided to the model and the way that the modeler has programmed phenomena to operate in the model. You do not compare a model against another model to validate its results. You compare a model against the real world and its ability to predict conditions in the future.
Furthermore, you cannot be confident that your model is complete and accurate when conditions change outside of the ranges of calibration data (the histortical data and present conditions produced by your model) that are provided to the model. I can guarantee that the solar flux and deep ocean circulation data used to calibrate the model before the advent of weather satellites and computerized oceanographic probes is of pretty poor quality before, say, 1970. So we have data through say, three solar activity cycles, and data that doesn't even cover a single instance of some of the longer term astronomical cycles. Yes, we have long term carbon dioxide data from ice cores, as well as the basic physics that say that CO2 increases net capture of infrared radiation, but to say that we have complete knowledge of the system is pure hubris.
Mind you, I buy that CO2 emissions play a role, I just don't buy that we know the system so well that we can say, in effect, that nothing else matters. The economic changes and generational sacrifices that must be made will change radically depending on whether 33% or 100% of the anticipated "warming" (really, change in regional conditions) is anthropogenic or otherwise.
"Dr Barnett said the results, which are about to be submitted for publication in a major peer-reviewed journal, should put further pressure on the Bush Administration to sign up to the Kyoto Protocol, which came into force on Wednesday. "It is now time for nations that are not part of Kyoto to reevaluate and see if it would be to their advantage to join," he said."
I'm also hoping that this particular paragraph is an example of poor quoting and writing by the reporter. If the lead scientist of the group is taking this strong of a public political position before the paper has even been peer reviewed, it is only going to hurt the perceived quality of the results.
Re:Indeed... (Score:2, Informative)
LEARN HOW TO FUCKING READ! (Score:3, Informative)
Do you agree with climate experts that global warming is well under way? [cnn.com]
So I guess the CNN website can be read by people in countries that CAN'T EVEN FIGURE OUT WHAT THE POLL QUESTION IS ACTUALLY ASKING.
Now, I believe that 'global warming' is going on, since we are coming out of an Ice Age but I don't believe it is man-made.
CNN words the questions in this way on purpose, they lead you to a conclusion by asking a question that will have the result they want.
The world is cooling, says NASA (Score:2, Informative)
The previous issue (Feb 12) has some good summaries of global warming, particularly addressing a number of "tipping point" dangers - problems that will be much more difficult or impossible to fix once a threshold had been passed. See http://www.newscientist.com/article.ns?id=mg185248 64.300 [newscientist.com]
for a teaser. You'll have to get the magazine for the full article. However a brief summary runs as follows:
Ocean conveyor belt shuts down=much colder climate for Western Europe.
Greenland's ice cap melts=higher sea levels (7 meters) over a long period (1000-3000 years). However, the problem is that a tipping point could be reached with only a 2.7 degree C rise - this means the meltdown would begin but not necessarily reverse even if temperatures subsequently dropped.
Methane released from undersea sediments (methyl hydrates)->accelerated warming because this is a greenhouse gas. The estimate is that there is something like 5 trillion (10^12) tonnes of methane under the ocean in this form.
Oceans become more acid because of dissolved CO2. This could disrupt CO2 sequestration by interfering with sea organisms like corals and shellfish.
Rate of CO2 buildup may increase because, after a little warming, organic material will decay more rapidly. The short-term effect of more CO2 is faster plant growth, hence more absorption. However, this trend can reverse at some temperature as decay speeds up.
No facts here (Score:5, Informative)
Re:Not millions, but here is 400,000 years worth (Score:1, Informative)
Re:Indeed... (Score:5, Informative)
To use comments out of context is a disengenous ploy. Willful ignorance and deceit are not virtous behaviour.
Re: Indeed... (Score:3, Informative)
> We have climate data from ice cores drilled into miles of ice in the ice sheets covering Greenland and Antarctica.
Also sediment cores from lake, sea, and ocean bottoms, and tree-ring samples. In some cases even the geological record can be useful, since annual deposition rates can tell us about freezes, melts, and droughts.
The amazing thing is that you can find this stuff out by simply reading a magazine or watching a television documentary now and then, and yet many intelligent people remain completely unaware of it.
Kyoto = Kommunist + Eurofag (Score:2, Informative)
Re:Indeed... (Score:5, Informative)
And the other fact you need to face is that modelers spends hours and hours tweaking their models until they "look right", and if "humans are the cause of global warming" is what looks right to them (and they get paid to get that result) then that is what the models say.
Perhaps this is true. But those on the other side do it as well - they also train their "there's no problem" models to fit all the weather data that is available.
Which is why this particular study is so very important - they didn't tweak the models, they took a bunch of existing tweaked models and applied them to another set of data. The models made predictions about ocean temperatures, but hadn't been tweaked with them.
And it turns out that the predictions of the "the greenhouse effect is currently causing warming" models were very close to the actual measurements, and the predictions of the "it's volcanic activity / a solar cycle / natural fluctuations in weather" models totally failed.
This study addresses exactly that criticism of yours, and it blows it away.
Re:Indeed... (Score:4, Informative)
We don't have thousands of years of weather data. We do have thousands of years of climate data, thanks to fossils and ice cores.
Weather data is specific, as in "67 degrees F and rained 1/4 of an inch".
Climate data is more general, such as "averages 50-70 degrees in winter, raining 10 inches".
We don't need to have collected weather data in order to get climate data, it just makes the climate data more accurate. But we can use the ice cores/fossils to say that, within a reasonable margin of error, the average tempature rose by 3 degrees over a particular 10,000 year period.
Re:Man.. (Score:4, Informative)
You're kidding me, right? Please tell me you are kidding. Even the EPA admits that "Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of U.S. carbon dioxide emissions" [1]
And regarding methane, yes it is more potent as a greenhouse gas, but livestock warming the earth? They don't contribute anywhere near as much aggregate effect as carbon dioxide.
1. http://yosemite.epa.gov/OAR/globalwarming.nsf/con
Global warming IS directly caused by humans! (Score:4, Informative)
This is silly. A significant majority of anthropogenic climate forcing is due to CO2 produced directly by burning fossil fuels.
Indirect contributions to CO2, such as deforestation is very small in comparison. This can be seen by observing that during the 18th and 19th centuries, deforesting large areas of North America caused a measurable, but very small increase in atmospheric CO2. Burning fossil fuels in the 20th century caused a large increase in CO2 levels. There are several ways to tell where the carbon is coming from: isotope analysis shows that most of the additional carbon is old on the scale of the carbon 13 lifetime, so it has not come from organic material formed in the last couple of hundred thousand years. Second, the timing and magnitude of the increase coincides directly with the growth of fossil fuel use and not with any other anthropogenic or natural phenomenon.
Methane gets a lot of press, but it only lives for a decade in the atmosphere before it's oxidized, whereas carbon dioxide has a much longer lifetime (around a century) so it poses a much greater threat.
Even if we consider methane, cow farts are only a small fraction of total anthropogenic methane emissions.
Re:The USA is a *net carbon sink* because of trees (Score:3, Informative)
The most important changes in land use affecting the U.S. share of the carbon budget are those that increase or reduce forest land. Each year, a very large amount of carbon dioxide, on the order of 100 billion metric tons, is removed from the atmosphere and sequestered into biomass and soil worldwide.
So biomass and soil accounts for 100 billion metric tons of carbon per year worldwide.
At the same time, carbon is released to the atmosphere from vegetative respiration, combustion of wood in natural or purposely set forest fires or as fuel, degradation of manufactured wood products, and the natural decay of rotting vegetative detritus.
But the same biomass is also responsible for the release of carbon.
The net numerical difference, or flux, between carbon sequestration and carbon release due to natural factors can be viewed as a measure of the relative contribution of biomass to the carbon cycle.
So by 'flux' they mean the net difference between sequestration and release, due to biomass.
Annual world carbon flux is difficult to measure but is thought to be close to zero; in other words, sequestration and respiration are roughly in balance worldwide.
So, across the whole planet, carbon flux from biomass is approximately zero (as one would expect for a steady state). Note that nowhere yet has emissions from any other source been considered!
In the United States, however, the live components of forests and the wood products produced from them (including paper and wood-based construction materials) sequestered a net of approximately 111 million metric tons of carbon (407 million metric tons of carbon dioxide) in 1992, including 12 million metric tons of carbon sequestered in wood products and 15 million metric tons of carbon sequestered in landfilled wood product waste.(112) A further 127 million metric tons of carbon were believed to be sequestered in forest soils and the forest floor in 1992. For purposes of comparison, this estimated amount of sequestered carbon offset approximately 17 percent of the 1,381 million metric tons of carbon (or 5,068 million metric tons of carbon dioxide) emitted in the United States in 1992 from the burning of fossil fuels (see Chapter 2).
This contains the real information. The US forests have a positive flux of carbon. ie, the amount of carbon stored in the forest per year is larger than the amount of carbon released by the forest per year.
BUT, this is only 17% of the carbon emitted by burning fossil fuels! So the USA is most definitely NOT a net sink of carbon!
Re:Hubris (Score:3, Informative)
You didn't. They took several models from other researchers and looked at what those models predicted in the way of deep-ocean temperatures (these models included ones that didn't attribute atmospheric warming to C02 increases). They then compared these predictions to the observed deep-ocean data. The models that showed C02-induced warming did a better job of predicting the temperature profiles; thus leading one to believe that the C02-related models did a better job overall. Conclusive? Maybe not - but nonetheless a good test.
if it only were cow farts (Score:4, Informative)
If cow farts were responsible for global warming, Kyoto would be a treaty on cow farts. Furthermore, methane has a short half life in the atmosphere, that would be really swell. Likewise, if deforestation were responsible for global warming, all the more reason to stop deforestation.
Unfortunatly for everybody concerned, it's easy to tell that cow farts are not the primary cause of global warming, CO2 is. CO2 has a long atmospheric half life, which means that we will have to live with the consequences of our stupidity for centuries.
In fact, what climate models really show is that other human activity (e.g., particulate emissions) has so far probably masked the full extent of global warming, so that things may actually already be further advanced than they appear based on our actual climate measurements. (And, in case you are wondering, we can't continue activities contributing to this masking effect because it has been killing huge numbers of people already.)