Slashdot Mirror
NASA Announces Record Ozone Hole
Drewsk writes "NASA has announced that the ozone hole over the Antarctic has broken all records. From the story: 'From September 21 to 30, the average area of the ozone hole was the largest ever observed, at 10.6 million square miles,' said Paul Newman, atmospheric scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. If the stratospheric weather conditions had been normal, the ozone hole would be expected to reach a size of about 8.9 to 9.3 million square miles, about the surface area of North America.""
The article states the following:
"these ozone-depleting substances typically have very long lifetimes in the atmosphere (more than 40 years).
Obsoleting Freon has helped, however it will take tens of years for the existing CFC/HFC/HCFC's etc gas levels to drop to acceptable concentrations.
Excuses Are Like Assholes - Everybody's Got One
RTFA. It kindly mentions that
A) Chlorine, Bromine, and their Ozone cappin' friends stay in the atmosphere for decades. Even with a significant drop in emissions (its precipitousness is reminiscent of the bunny slope) it will be a very long time before significant positive effects accrue. As the article points out, we can expect about 0.1% to 0.2% per year in the near term.
B) This record breaking event is the culmination of several phenomena, including large-scale, seasonal factors that completely overshadow the tiny bit of healing the layer has done in the last few years. "This slow decrease is masked by large year-to-year variations caused by Antarctic stratosphere weather fluctuations."
One thing the article does NOT mention is any cry of "Wolf!". There isn't any environmentalist finger-wagging, just some scientists saying "holy shnikes, take a look at the SIZE of that thing!!"
The ozone we're concerned about here is formed by solar ultraviolet in the stratosphere. Almost all thunderstorm activity is in the troposphere. The ozone that thunderstorms and photochemical smog produce only lasts a few weeks.
Now, if you want to get confused, CFCs are both catalysts of ozone breakdown and greenhouse gases. To make you even more confused, upper tropospheric ozone is a greenhouse gas, not as important as CO2 but worth taking into account.
Sure! Your intuition is far more powerful than 100 years of scien-ma-tific observation.
Although the presence of ozone in the atmosphere has been known for a bit over 100 years, knowledge of the presence of a permanent ozone layer is rather more recent. Man did not reach the south pole until 1912 and did not fly over it until 1929. The first permanent observation station at the south pole was not established until 1957. Meanwhile the ability measure the thickness of the ozone layer, from either ground or satellite is concurrent with the discovery of the ozone hole. Mid 70s through mid 80s. Although ballons have been flying into the stratosphere for a couple ticks over 100 years, we only got a good idea of its structure in the mid 80s when we sent up an instrumented U2. OP is right to the extent that we really know squat all about the history of the ozone layer.
Go back to eighth grade science class, then come back and post on slashdot.
I had just finished my undergraduate studies in physics when we first started acurately measuring the thickness of the ozone layer indirectly; and thus being able actually map it. Perhaps you have the advantage on me of only recently being out of the eighth grade.
KFG
certainly not for those of us who have to live under it.
I live in New Zealand, the current position and shape of the ozone hole is a regular feature of TV weather reports.
There are two possibilities that don't defy logic:
The real problem is a hundred years of devices using freon rotting in dumps worldwide. There were projections of it rising for a number of decades before it started to drop perminately. Actual recovery will take a couple of hundred years. Recycling of the devices would help but most of the world isn't willing to spend the money and even the US has a poor record for recyling old refridgerators and such. Just imagine all the millions of rusting cars leaking freon from old AC units. Most refridgerators in this country don't use freon but there's still some older ones in service and oceans of them in dumps. Add to that old paint spray cans and hair spray cans. Look on the brightside how bad would it have been if we hadn't stopped? Australia and New Zealand might have been covered by the hole by now. I spent some time in New Zealand a half a dozen years ago and skin cancer was common there. People didn't tan they burned. Better to start recovery now than waiting there is no ozone layer and everyone is getting skin cancer. When I was growing up I had never heard of skin cancer. Now I'm one of the few people I know over forty that hasn't had it and I know people in their twenties that have had skin cancer. Teens and children are getting it. It's one of the great unspoken plagues.
http://en.wikipedia.org/wiki/Ozone_depletion#CFCs_ in_the_atmosphere, and the text below that section, seem to call bullshit on your assertion that CFCs have no effect on the ozone.
== Jez ==
Do you miss Firefox? Try Pale Moon.
no-one has ever explained how CFC molecules which are much heavier than air, can rise up in the stratosphere, travel all of the way to Antarctica before being broken down into chlorine and fluorine and reacting the O3
Maybe not, but they're there. All the same tools that tell us whats in other planets' atmospheres works equally well on our own. Further more, as surprising as it may be, if you lay down on the ground, you're not likely to asphyxiate unless someone dumps a sufficient amount of a heavy gas right next to you, since the atmosphere mixes up rather easily. As for how they move, I'm going to suggest things like the Jet Stream for moving them around the planet, and equatorial heating to carry CFCs into the upper atmosphere and down towards the pole.
Chlorine in the ice
Interesting theory. Where did the chlorine come from? A molecule of Cl2 (total atomic mass 71) is more massive than N2 (28), O2 (32), and CO2 (44), or does "too heavy" only count when it's you saying it? Could it possibly be that the Cl in your ice is the same Cl in CFCs?
thus turning your refrigerator into a potential BOMB.
Aside from someone else already pointing out that it's not benzene, I guess you're too young to remember the days of early ammonia refrigerators, now those were the BOMB!
My God where did you get your meteorology degree?
Tropospheric ozone is created by many things but is very reactive and does not last long. Lightning does produce ozone in the troposphere as does certain chemical reactions between anthropogenic pollutants.
Stratospheric ozone is created when high-energy ultraviolet light from the sun splits diatomic oxygen (O2) into oxygen atoms (O) which can combine with O2 to create O3. UV also splits O3 into O and O2, and there is constant creation/destruction of O3 in the strasophere. It reaches an eqilibrium which is a function of a bunch of things, but the end result is (a) the creation/destruction of O3 in the stratosphere "absorbs" the most energetic UV from the sun (which is good for life) and (b) this process heats up the stratosphere, making it one big inversion which has the nice side-effect of keeping thunderstorm updrafts from blasting into the mesosphere.
In order to undertsand why there is an ozone "hole" over Antarcitca you have to understand about the dynamics of the atmosphere. Most ozone is actually created in the tropical latitudes and is advected southward/northward via the Hadley Cell circulation. The polar vortex over Antarctica tends to inhibit mixing across its boundary, so stuff that gets in it tends to stay there. Ozone depletion due to CFCs tends to be greatest around this time of year when the Antarctic is entering Spring and the sun is beginning to interact with polar stratospheric clouds which are a major catalyst to the ozone depletion.
Anyone could look this stuff up in a recent undergraduate meteorology textbook. Just about all of the "Mod 5 : informative" posts in this thread are laughingly incorrect.
Same goes to the douche who thinks "CFCs are too heavy to get into the Stratosphere". I'm not going to bother to explain that one to you.
And finally, don't ever mention "global warming" and "ozone hole" in the same sentence as if they are related. They are not.
A squid eating dough in a polyethylene bag is fast and bulbous, got me?
Here's a brief explanation:
CFCs need to leech from the troposphere to the stratosphere. The troposphere is very easy to travel through, as temperatures decreases as you approach the stratosphere. This allows for the warmer air near ground level to rise to the top of the troposphere, where it cools and sinks back to the ground (which then warms again, etc). This makes sure that pollutants such as CFCs travel very well throughout the troposphere.
However, the stratosphere warms as you go higher. The cooler air down below sinks back into the troposphere, making it hard for pollutants to enter it. The stratosphere is where the ozone is. The only way for the gas to get into the stratosphere is to diffuse very slowly into it, where it can do its damage.
This is why there is such a big hole now. Diffusion into the stratosphere takes many years. Scientists have predicted a peak in CFC levels in the stratosphere around about now. Slowly, all the CFCs we've produced will diffuse, react to become relatively harmless free radicals, and the ozone layer will be restored. Until then, sit tight.
You know, there is a difference between trolling and pointing out the flaws in your reasoning. Just saying.
Same goes to the douche who thinks "CFCs are too heavy to get into the Stratosphere". I'm not going to bother to explain that one to you.
.9%). If the heaviest gases simply sunk to the bottom, we would be suffocated by argon near the ground and all of the nitrogen would be on the top of the atmosphere, with the oxygen in the middle.
Actually, I'd really like to hear an explanation. I'm not going to claim to know anything about CFC's, but if these gases really are heavier than air and don't readily mix with air, how exactly does a bucket of them in my back yard elevate itself to the upper atmosphere?
Think of it this way: What is "air" in the first place? To a good approximation within the troposphere, it's a mixture of molecular oxygen (molecular weight = 32 grams/mol, 21%), molecular nitrogen (MW = 28 g/mol, 78%) and argon (MW = 40 g/mol,
The troposphere (tropos in Latin means "turning" or "mixing") is well-mixed and the relative ratio of the three aforementioned permanent gaes to one another is constant. If you introduce a heavier gas (higher MW) it will still get mixed into the lighter gases over time due to the winds. Brownian motion will also cause heavier gases to diffuse in a calm environment.
CFCs will spread laterally across the globe by the horizontal winds. Whenever there is a strong thunderstorm, updrafts will slam air, which originates near the ground, into the tropopause, the boundary between the troposphere and the stratosphere. Very strong updrafts can intrude into the bottom of the stratosphere where the tropospheric air mixes into the stratosphere. Once something gets into the stratosphere (if it's got a very small terminal velocity - think about strong volcanoes spewing ash) it tends to stick around because the stability of the stratosphere is so high (due to the temperature inversion I mentioned before).
Back to "heavier gases" for a moment. It is true that if you "pour" a heavy gas onto the ground it will spread out before mixing. There have been cases where CO2 (MW = 34) has seeped out of the ground and spread laterally, suffocating people (google Lake Nyos). But given a few hours of typical winds, the heavier gas will be diluted and over time mixes into the rest of the atmosphere, contributing slightly towards the atmosphere's own average molecular weight.
A squid eating dough in a polyethylene bag is fast and bulbous, got me?
Nice try. Grains of dust are trillions of times heavier than a molecule of air or CFC, and don't mix with it, yet they can be blown miles into the atmosphere and across oceans without immediately settling to the ground. The suggestion that CFCs can't reach the stratosphere based on their relative weight is entirely bogus. It'd be true if there were no air currents agitating the atmosphere, but that's not the case.