No, this is not Steve McIntyre finally coming out with his own multi-century proxy temperature reconstruction. Nor is it Anthony Watt's release of his surfacestations.org temperature reanalysis.
It is the take away figure from a recent paper in Nature by Kinnard et al that reconstructs the extent of arctic sea ice over the last 1450 years.
Tamino has a discussion of it here.
There is not really much to add to the thousand words that image conveys.
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Are we not still coming out of an ice age? You know, the one that ended roughly 10,000 years ago and allowed for the development of all of human civilization. Could this just be an extension of that? Is it possible we have a much colder future on our hands when the ice returns?
No. Clever of you to have thought of it though.
JJ and Ethan:
Are you saying this is good?
As you say, we came out of it 10K years ago at which point a very slow general cooling trend occurred. The Milankovic cycles that control the timeing of ice ages would have as enter a new glaciation in some 30-50K yrs. What our CO2 emissions are doing completely overwhelms that underlying cycle.
Absent the current unplanned and drastic intervention, I would have agreed that preventing another galciation might have been a worthwile proposal, in say, 32000AD.
"....Is it possible we have a much colder future on our hands when the ice returns?...."
I have no doubt that the ice will return and we will have a colder future on our hands. But you and I probably won't be here in 10,000 years.
On the other hand, our children and grandchildren will be here on the next century or so to suffer the consequences of our foolishness in failing to change our ways to mitigate climate change.
"the one that ended roughly 10,000 years ago"
Nearer 18,000 years.
And after the warm rebound at the beginning of the exit from an ice age (the first thousand years or less), the trend thereafter is downward until the temperatures drop and feedbacks cause another ice age.
We shouldn't be warming at all at this stage.
Along with the sun getting warmer, if this AGW continues the earth may never find another ice age.
Good. I'm fed up with paying ever-increasing costs for heating oil.
Move south, then you lazy misanthrope.
Or will you put up the refugees from Mexico who can't survive in the heat down there?
Don't get me wrong. I firmly believe that the earth suffers the consequences of our actions. I just dismiss the idea that the Earth will be radically altered over the course over a time period as short as 200 years. A temperature rise of one or two degrees over three hundred years is in effect, negligible. Besides, given the advancements in technology we have seen in the past 100yrs what can we expect from our "Children and Grandchildren".
I also take issue with any data sets that contain information collected prior to the invention of the radio. Yes, you all the information you can from ice cores and things of that nature, just do not expect me to blindly follow the numbers provided to me from atmospheric composition tests done in the 1800's
What do you mean by 'radically'? Do you think it likely that 100 years from now there will still be significant amounts of summer ice in the Arctic? What is your justification for that belief?
Who uses them in their arguments (cite to an actual paper using them, please)?
Cowardly, Richard. Love it
â.....Don't get me wrong. I firmly believe that the earth suffers the consequences of our actions....â
The Earth will go on just fine without us, and will not suffer one little bit because of our actions. But we will, and so will lots of other species.
â....I just dismiss the idea that the Earth will be radically altered over the course over a time period as short as 200 years....â
So you are just a denier then? Rather than just âdismissingâ something that you donât understand regarding an issue for which you have no education, why donât you go and find out some facts?
â....A temperature rise of one or two degrees over three hundred years is in effect, negligible....â
Really? And on what basis do you come to that earth-shattering conclusion? Once again, you are living in a fact free zone. A two degree temperature change is the difference between an ice age and the current interglacial. An additional two degrees will cause max extinctions on a scale not seen for millions of years. And what makes you think climate change will be limited to 2 degrees? Try doing some reading on the subject before making a fool of yourself:
â....I also take issue with any data sets that contain information collected prior to the invention of the radio.....â
Radio huh? And in what way does the invention of radio affect the collection of data? I would be fascinated to read your response on that one.
â....just do not expect me to blindly follow the numbers provided to me from atmospheric composition tests done in the 1800's...â
Well, first of all, scientists NEVER blindly follow numbers. They check, and double check. That's why the use multiple sources of information to confirm analyses. Perhaps you should do some reading on that one as well. You know - about the ice cores you mentioned. And there are many others, such as tree rings, speleothems, coral, sediment, pollens, etc, etc.
And I am wondering what âatmospheric composition tests done in the 1800sâ have to do with anything. Perhaps you can explain.
I've not the slightest idea wwhat you are getting at here. You'll have to explain.
"I just dismiss the idea that the Earth will be radically altered over the course over a time period as short as 200 years."
I can understand why you might. 2oC change is hard to even notice as you go about your daily affairs. However the problem is that our intuition, or gut feeling, about seemingly small changes in globally averaged temperature is just not up to the task of making this conclusion. There is nothing in any person's personal experience to guide expectations of the impact of 2oC change in global climate.
So rather than just bow to your own ignorance and snort at warnings from just about every one who has educated themselves on this subject, why don't you try to find an historic event of comparable warming in rate and magnitude? If you see that in the past this has happened and all was well, then you would at least have some reason to trust your own judgement.
But if you do examine some past climate change events you will find that your intuition is wrong. For example, a mere 5oC change in global temperature is the difference between kilometre thick ice sheets as far south as the contenintal US and the climate we had during the last 8K years or so. 5oC! This transition also happened at a rate about 30x slower than today's rate of change, and perhaps 100x slower than what may be coming if climate models are correct. And that is just one example. Other historical warnings we would do well to heed include the PETM event and the "Great Dying" of some 250M years ago.
Richard, I share your confusion! Jon...huh?
It's the Snowman effect, I think--the idea that only pussies rely on rigorous research and what it actually says. To the extent you do this Richard, you are, in JJ's mind, like the chickenshit kid on the playground that goes and gets his big friends to resolve a fight for him.
Like JJ here, a lot of climate deniers see this debate as strictly rhetorical, not factual. (Snowman even admitted as much.) This is why at sites like Wattsup they cheer whenever a new poll comes out showing that more than half of Americans deny climate change--as if this in itself vindicates their denial. They aren't interested in the objective truth, only that their version of it prevails.
JJ sees himself as a stalwart defender of a bold position. What does research have to do with such matters of honor? Let the sniveling scientists and their audience whine about their "facts" all they want . . .
I just love the notion that 2 degrees is trivial.
Well I suppose it is trivial from the point of view of a planet or a solar system. But a tiny smidgen more than 2C is the difference between New York state as we know it and New York state _and city_ under 2 miles of ice.
Not trivial for us.
"For example, a mere 5oC change in global temperature is the difference between kilometre thick ice sheets as far south as the contenintal US and the climate we had during the last 8K years or so"
What's weird is that the much-lauded by deniers paper saying that climate sensitivity is lower than the IPCC estimate has the temperature difference between those two situations not 5 degrees C but only 3 degrees C.
Skip: Your explanation sounds as plausible as any. Perhaps they do see coming to a discussion about science armed with actual facts and evidence as being somehow cheating.