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The ozone hole over Antarctica does more than let a little extra ultraviolet light reach ground level: It boosts ocean acidification in the waters surrounding the icy continent and reduces the amount of carbon dioxide emissions those waters can absorb.
Recent research has indicated that the oceans surrounding Antarctica aren’t absorbing nearly as much planet-warming CO2 from the atmosphere as they did in previous decades (SN: 5/26/07, p. 333). In one of those studies, scientists speculated that meteorological effects of the high-altitude ozone hole over Antarctica, including strengthening of winds at sea level, might be to blame. Now, results of computer simulations bolster that notion, researchers report online June 20 in Geophysical Research Letters.
Francis Codron, an atmospheric scientist at the French national center for scientific research, CNRS, in Paris, and his colleagues used climate models to compare two scenarios: one in which the stratosphere over Antarctica had no ozone hole from 1975 to 2004 and one in which the stratosphere had a hole like the one that has actually developed. The researchers ran five simulations for each of the two scenarios, Codron says.
“This is a nice study,” says Jorge Sarmiento, a biogeochemical oceanographer at Princeton University. This team’s ocean-atmosphere simulations are the first to include effects of the ozone hole, he notes.
The average results of the two scenarios differ little from 1975 to 1986.. From 1987 onward, however, wind speeds over the high-latitude southern oceans were higher in the ozone-hole scenario than in the simulations that lacked an ozone hole. Differences between the scenarios became larger with every passing year, the researchers report. In the ozone-hole scenario, wind speeds in some areas were 60 percent higher in 2004 than they had been in 1975.
That increase in wind speeds has triggered a series of real-world effects, Codron suggests. First, the stronger winds stir the surface waters more effectively and boost the upwelling of waters from the deep — waters that include large amounts of dissolved CO2 from the decomposition of ocean life that died and sank to the depths. As the surface waters become more enriched in CO2, they can absorb less carbon dioxide from the atmosphere, explaining the reduced uptake of that gas previously noted by scientists. The simulation suggests that between 1987 and 2004, the southern oceans absorbed about 9 billion metric tons less CO2 than they would have without the ozone hole.
The increased concentrations of dissolved CO2 also boosted the ocean’s acidity in the ozone-hole scenario. Surface water pH dropped — meaning the water became more acidic — by about 0.02 units, about 10 percent of the change measured in oceans since the beginning of the Industrial Revolution.
For the next half century — the period that scientists estimate it will take for the ozone hole to heal itself after banning ozone-destroying chemicals (SN: 12/24/05, p. 418) — reduced CO2 uptake in the southern oceans could exacerbate or speed the effects of climate change globally.
Found in: Climate Change, Earth, Earth Science and Environment
- Perkins, S. 2007. Southern seas slow their uptake of CO2. Science News 171(May 26):333. [Go to]
- Perkins, S. 2005. Ozone hole might not recover until the year 2065. Science News 168(Dec. 24):418. [Go to]
- Lenton, A., F. Codron, et al. 2009. Stratospheric ozone depletion reduces ocean carbon uptake and enhances ocean acidification. Geophysical Research Letters 36(June 28):L12606-1. [Go to]
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More results of more computer simulations is not real science. Science should be what went into making the models, not what comes out of them. But even that's not the case here. Climate models are largely based on curve-fitting, not first principles. If the models were any good, there would be only one of them.
And, of course, we have evidence of the usual pro-anthropogenic global warming bias so characteristic of the "new" sensationalized, non-objective Science News:
"...planet-warming CO2..."
"For the next half century — the period that scientists estimate it will take for the ozone hole to heal itself after banning ozone-destroying chemicals..."
Give me a break!
Modeling is not science at all unless it is based on scientific principles and evidence. Climate models are not based on evidence. Even if they were, they would not be very useful. The IPCC admits as much (IPCC, 2001):
"In climate research and modeling, we should recognize that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible."
There you have it, right from the horse's mouth.
And you're telling me that this is science? Come on!
This has nothing to do with Republicans (thank God), but with our media. The original article would probably not have passed peer-review 20 years ago; even if it did Science News used to be a very respectable publication and they would have included some "balance" in this story so that the other side was heard. Not any more. Science itself suffers as a result.
Your assertion that we are far from completely confident about our climate predictions is correct. Since we don't know really the full effects of raising CO2 levels and all life depends on our one and only atmosphere we should immediately stop this unplanned and reckless experiment.
from http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch08.pdf
"There is considerable confidence that climate models provide
credible quantitative estimates of future climate change, particularly
at continental scales and above. This confidence comes from the
foundation of the models in accepted physical principles and from
their ability to reproduce observed features of current climate and
past climate changes. Confidence in model estimates is higher
for some climate variables (e.g., temperature) than for others
(e.g., precipitation). Over several decades of development, models
have consistently provided a robust and unambiguous picture of
significant climate warming in response to increasing greenhouse
gases.
Climate models are mathematical representations of the climate
system, expressed as computer codes and run on powerful
computers. One source of confidence in models comes from the
fact that model fundamentals are based on established physical
laws, such as conservation of mass, energy and momentum,
along with a wealth of observations.
A second source of confidence comes from the ability of
models to simulate important aspects of the current climate.
Models are routinely and extensively assessed by comparing
their simulations with observations of the atmosphere, ocean,
cryosphere and land surface. Unprecedented levels of evaluation
have taken place over the last decade in the form of organised
multi-model ‘intercomparisons’. Models show significant and
increasing skill in representing many important mean climate
features, such as the large-scale distributions of atmospheric
temperature, precipitation, radiation and wind, and of oceanic
temperatures, currents and sea ice cover. Models can also simulate
essential aspects of many of the patterns of climate variability
observed across a range of time scales. Examples include
the advance and retreat of the major monsoon systems, the
seasonal shifts of temperatures, storm tracks and rain belts, and
the hemispheric-scale seesawing of extratropical surface pressures
(the Northern and Southern ‘annular modes’). Some climate
models, or closely related variants, have also been tested
by using them to predict weather and make seasonal forecasts.
These models demonstrate skill in such forecasts, showing they
can represent important features of the general circulation
across shorter time scales, as well as aspects of seasonal and
interannual variability. Models’ ability to represent these and
other important climate features increases our confidence that
they represent the essential physical processes important for
the simulation of future climate change. (Note that the limitations
in climate models’ ability to forecast weather beyond a
few days do not limit their ability to predict long-term climate
changes, as these are very different types of prediction – see
FAQ 1.2.)"
Models test scientifically established theoretical constructs based on and guided by - when available - actual measurements. If our understanding is even remotely correct, then a model can say LOTS about 'if' and 'along which parameters' a system may respond when impacted by different forcings. Or even reveal what directions future 'real-world' science questions should be asked to move forward with our understanding.
Extrapolation of model output to the physical world is 'iffy', for certain. Unfortunately that is the most straightforward way to try and make any real sense of the output. But it is certainly science per execution of the scientific method.
And - as for Cl and Br in the stratosphere. Most of it, in the atmosphere, is in the form of ions. The photochemically reactive form is more along the lines of that which you'd put in a pool to disinfect it (e.g. bleach). Volcano emission of Cl and Br is ionic. Algal and biomass emissions of reactive halogen compounds are too unstable to ever make it up to the stratosphere - they get cooked quickly and live totally within photochemical cycles in the boundary layer and troposphere. CFC's are stable enough to make it up there.
Engineering models are based on known and well-understood differential equations of deterministic physical processes.
Climate models, unlike engineering models, include some well-understood differential equations, but are largely based on empirical curve fitting of poorly-understood earth processes, some of which are chaotic. They are "calibrated" using historic temperature data (which itself has been manipulated and may well be biased). Thus they are only as good as the empirical guesswork that went into their development. The IPCC claims to get around this by running the models many times, Monte Carlo sytle, and getting a probability distribution of the result. This method cannot compensate for knowledge NOT in the model to begin with.
If you don't understand it, you cannot model it. Period.
Climate models only serve to exaggerate the "opinions" of the modelers (i.e. the poorly understood empirical relationships) coded into them. In this sense, they are not at all scientific.
Fourier tried solving an analytical "model" (differential equation) for the earth's temperature in the 1700s, long before computers, but he couldn't do it because the boundary conditions depend on the temperature distribution. Can't be done, even in principle. We are not much better off today.
Sorry, but the model results have no credibility.
And the article gives you the impression that someone actually went out and measured something. Shameful.
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