A few years back, the Northwest Passage became free of sea ice, for the first time in hundreds of years. This was heralded as the prooff of arctic warming. now i hear that we are experiencing a very cold winter-so has the sea ice returned?
Also-an american entrepreneur bought the (Canadian) port of Chrchill (on the Hudson’s bay). his plan was to turn the port into a major shipping point to Europe-which would be assisted if the bay were to become ice-free throughout the year. has this come about, or is he screwed?
The sea ice is being melted back farther in the summer than it has since we started recording such things. The sea ice returns every winter so far. No one has ever claimed otherwise. It’s the extent of the meltback in the summer that’s concerning people, because the ecosystem above the Arctic Circle depends on SOME sea ice remaining in the summer.
The thing to remember, though, is that the Arctic sea ice is more of an indicator than a problem in itself. It’s the Antarctic ice that’s the big deal. Arctic sea ice is (mostly) floating. When it melts, it doesn’t raise the sea level because it was displacing by weight (as ice) the same volume it will displace as water. It’s the land ice (Greenland, northern Canada and Antarctica) that’s troubling, because if a significant portion of all of that melts, it WILL raise sea levels because it’s not displacing its full weight in water at the moment.
And there are many shippers anticipating an advantage in the coming years from a more navigable Northwest Passage. Canada’s claims to sovereignty in the region are also taking on new significance - they are claiming the right to regulate traffic through it, whereas most other nations believe it to be international waters.
Yearly variations in weather are far greater than the tiny changes caused by Global Warming. Thus, at no time can the weather “at this point in time” show any significant GW changes. GW works over decades, not years.
Was just reading an article on this yesterday and almost started a thread on it. Wish I remembered where that article was now…I’ll try and dig it up later today if I get the chance. Essentially the article was saying that water temperatures (and other factors) are still thinning out the ice. They were pointing to several ice sheets near collapse in Antarctica as examples. The gist of the article though was that no, the assessment that sea ice has returned to it’s former levels is incorrect. That during the winter sea ice always expands and in summer it contracts, but the expansion is less and contraction more today than since they have been keeping records.
-XT
Quite true - and the opening of the Northwest Passage was far more a symbolic event pointing to the changes happening to the Arctic over time than it was the important piece of evidence, in itself, of climate change which ralph124c presents it as.
Just as one swallow does not herald summer, one cold winter (or even two or three) does not disprove global warming - anthropogenic or natural.
Not only that, but if it even slides off the land without melting (thereby becoming sea ice), that’d also raise ocean levels, by just as much as if it had melted. And some of these big glaciers are getting lubricated by small amounts of their bottom surface melting, which leads to fears that large chunks might indeed slide off into the sea.
Nor does one warm season prove it. (Not that I am arguing that GW doesn’;t exist mind you)
More, in fact, since ice is er… I don’t think I recall the scientific term. Expansive compared to water ? Frozen water takes up more volume is what I mean. Experiment with sealed water bottles and a freezer (but not with glass bottles if you don’t want to hurt yourself). So if anything, melting icebergs actually make sea level drop (the same way that ice cubes melting make your glass level drop). Your point is still valid though.
That’s not the way it works. The level of water in a glass with ice stays the same as the ice melts, because floating ice, while having more VOLUME, displaces its WEIGHT in water. When the cube melts, the weight of water is the same as the weight of the original ice cube, so the displacement is the same. This may be very slightly different in salt water than fresh water, but I don’t think it’s a significant difference.
:smack: Obviously you’re right. Must stop posting while stupid.
The key point though is that much of the sea ice that is connected to land in the Antarctic sort of acts as a stopper and control for the inland glaciers. Without that stopper the glaciers will move faster…and THAT will significantly add to the rise in sea level, even if the melting sea ice doesn’t.
From memory the ice is both shrinking and (more importantly) thinning.
-XT
One complicating factor is that GW is not uniform. The average temp in the arctic is rising 2-3 times faster than the global average. This is for many reasons mostly due to some positive feedback cycles. (things like meltwater absorbs more radiant energy than ice. When the permafrost melts the frozen peat decays releasing more CO2 which…).
So the arctic will have greater than average changes due to GW. That said, even the arctic changes are smaller than the inter-annular variability. So we will have more cold years, but not as many as we would w/o GW.
Another factor to consider is related to your point. Warm water expands. Almost half of projected sea level rise in the next hundred years is due to the fact that the average temperature of the existing water in the ocean will increase and increase the volume. So even if the GW didn’t melt the ice (it will) the increasing temperature will increase sea level.
Well, of course the planet is 4.5 billion years old. Your decades are meaningless to me. Let the flames begin, but I mean come on! A few decades! A few decades! This is what disturbes me most about all this AGW shit. So, we’re going to predict the future based on 2 or three decades of data? You gotta be kidding me.
What do you mean, “2 or three decades of data”? Temperature records and atmospheric gas concentration records have been reconstructed from Arctic ice cores for a period extending back at least 650,000 years.
We have data about greenhouse-gas concentrations in the atmosphere at corresponding points in successive glacial-interglacial cycles going back for a very long time. So yes, we can compare some aspects of today’s climate with conditions in earlier interglacial periods.
Why do you find this disturbing? Were you under the impression that climate scientists didn’t actually know anything about climate conditions hundreds of thousands of years ago, and were just speculatively extrapolating all their conclusions from temperature records within the last century? If so, that impression is wrong.
And the majority of that time there was no permanent ice or snow cover, anywhere, and places like Denmark, the Netherlands, most of Florida, and the Mississippi Valley south of Keokuk were shallow ocean.
In fact, the majority of that time, multicellular organisms other than filamentous algae did not exist.
BTW, it’s junior modding to be sure, but your opinion, or mine, about the validity of AGW does not belong in GQ. What this thread is discussing, at Ralph’s behest, is whether the ice cover of the Arctic Ocean has returned, and by extension the implications of seasonal changes on longer-term climatic change. Might I suggest, if you want to express your opinions on “all this AGW shit”. that you do it in the Pit?
If you’re going to be so angry about this, wouldn’t it be wise to actually learn something about what is pissing you off so much?
You’re spouting and frothing something fantastically ignorant there.
Here’s the Republican created and generally Republican run EPA’s view on global warming: