While planet earth has warmed only 0.6C on average over the last 150 or so years, warming in the artic has been more significant.
Clifford Kauss et al have written in the New York Times about new opportunities in the Artic as the ice melts:
It seems harsh to say that bad news for polar bears is good for Pat Broe. Mr. Broe, a Denver entrepreneur, is no more to blame than anyone else for a meltdown at the top of the world that threatens Arctic mammals and ancient traditions and lends credibility to dark-visions of global warming.
Still, the newest study of the Arctic ice cap – finding that it faded this summer to its smallest size ever recorded – is beginning to make Mr. Broe look like a visionary for buying this derelict Hudson Bay port from the Canadian government in 1997. Especially at the price he paid: about $7.
By Mr. Broe’s calculations, Churchill could bring in as much as $100 million a year as a port on Arctic shipping lanes shorter by thousands of miles than routes to the south, and traffic would only increase as the retreat of ice in the region clears the way for a longer shipping season.
Keep reading here …
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
I understand that the port on Arctic will be very profitable for Pat Broea but for how long? May be is better to buy land on an other planet!
Antonis Symeonakis
I thought polar bear numbers were stable or increasing? – current world estimate: 22,000 – 27,000.
In Canada the Govt organise hunting trips to keep numbers down.
http://pbsg.npolar.no/
http://www.nwtwildlife.rwed.gov.nt.ca/Publications/speciesatriskweb/polarbear.htm
Or is it that they are driven closer to settlement as their environment changes – hunting opportunities diminish.
The hunting trips don’t seem to be a free-for-all either.
I think really good data are hard to find but there is a fair margin for long term concern. Read your own references closely.
The Chinese Ming Dydnasty fleets commandednby Zheng He before the start of the little Ice Age mapped the northern Siberian coast. To do that they had to have clear access to the arctic ocean.
Awkward facts be, are they not?
That Ming Dynasty stuff can’t be taken seriously though. How would we know that it’s correct.
Phil Done,
May I suggest you research the literature? It is quite substantial.
And in a similar vein one might ask how do we know your global warming hypothesis is correct? There is certainly no obvious physical evidence, just artfully contrived computer simulations. But we do take this global warming seriously because its proponents base their ideas on junk science, not hard irrefutable fact.
I suggest you start with http://www.1421.tv and then follow on from there.
No you don’t have any evidence that the Ming stuff is right. Utterley none. It’s just hearsay.
And Louis might I suggest to that you research the literature on the other topic – a chore which you fail consistently to do. SO I’ve decided to adopt your philosophical position. I think it’s effective.
*I think really good data are hard to find but there is a fair margin for long term concern.*
There’s always a margin of concern Phil, thats why I am concerned at the conclusions arrived at despite the lack of good data.
So that means we just blaze away ? that’s intelligent … well shucks paw … dems no darn guud data … so I just bagged me a few baars….I likes shootin baaars .. does em good.
(well actually from an ecological point of view there is “enough” information to be concerned enough that we should know more on populations dynamics, pollution, and effect on ice retreat …)
Phil, I have researched the literature on the other topic, hence my firm criticism of it.
A chore which I consistently fail at ?
Incidentally I still await you and Ender explaining how Greenland froze up at the end of the MWP.
I don’t need to research it – it’s baloney. There’s no firm evidence. You haven’t supplied any.
And were you around at the end of the MWP – who says it froze up??
Any references of substance?
Louis – No – I will do what you do. Make outlandish and unsupported statements and then leave them.
Ender,
And you still have not explained how Greenland froze up, have you.
OK Louis – inform us oh oracle as to why it “froze up”. What’s your mechanism. And what’s your evidence.
Something like this Louis … I suspect you’re not into excitation bond lengths …
The natural greenhouse effect
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Process
The earth receives an enormous amount of solar radiation. Just above the atmosphere, the solar power flux density averages about 1367 watts/m2, or 1.28 * 1014 watts over the entire earth. This figure vastly exceeds the power generated by human activities.
The solar power hitting earth is balanced over time by a roughly equal amount of power radiating from the earth (as the amount of energy from the sun that is stored is small). Almost all radiation leaving the earth takes two forms: reflected solar radiation and thermal blackbody radiation.
Solar radiation at top of atmosphere and at Earth’s surface.Reflected solar radiation accounts for 30% of the earth’s total radiation: on average, 6% of the incoming solar radiation is reflected by the atmosphere, 20% is reflected by clouds, and 4% is reflected by the surface.
The remaining 70% of the incoming solar radiation is absorbed: 16% by the atmosphere (including the almost complete absorption of shortwave ultraviolet over most areas by the stratospheric ozone layer); 3% by clouds; and 51% by the land and oceans. This absorbed energy heats the atmosphere, oceans, land and powers life on the planet.
Like the sun, the earth is a thermal blackbody radiator. So because the earth’s surface is much cooler than the sun (287 K vs 5780 K), Wien’s displacement law dictates that the earth must radiate its thermal energy at much longer wavelengths than the sun. While the sun’s radiation peaks at a visible wavelength of 500 nanometers, earth’s radiation peak is in the longwave (far) infrared at about 10 micrometres.
Atmospheric absorption of various wavelengths of electromagnetic radiation (measured along sea level).The earth’s atmosphere is largely transparent at visible and near-infrared wavelengths, but not at 10 micrometres. Only about 6% of the earth’s total radiation to space is direct thermal radiation from the surface. The atmosphere absorbs 71% of the surface thermal radiation before it can escape. The atmosphere itself behaves as a blackbody radiator in the far infrared, so it re-radiates this energy.
The earth’s atmosphere and clouds therefore account for 91.4% of its longwave infrared radiation and 64% of the earth’s total emissions at all wavelengths. The atmosphere and clouds get this energy from the solar energy they directly absorb; thermal radiation from the surface; and from heat brought up by convection and the condensation of water vapor.
Because the atmosphere is such a good absorber of longwave infrared, it effectively forms a one-way blanket over the earth’s surface. Visible and near-visible radiation from the sun easily gets through, but thermal radiation from the surface can’t easily get back out. In response, the earth’s surface warms up. The power of the surface radiation increases by the Stefan-Boltzmann law until it (over time) compensates for the atmospheric absorption.
The surface of the Earth is in constant flux with daily, yearly, and ages long cycles and trends in temperature and other variables from a variety of causes.
The result of the greenhouse effect is that average surface temperatures are considerably higher than they would otherwise be if the earth’s surface temperature were determined solely by the albedo and blackbody properties of the surface.
It is commonplace for simplistic descriptions of the “greenhouse” effect to assert that the same mechanism warms greenhouses (e.g. [1]), but this is an incorrect oversimplification: see below.
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Limiting factors
The degree of the greenhouse effect is dependent primarily on the concentration of greenhouse gases in the planetary atmosphere. The carbon dioxide-rich atmosphere of Venus causes a runaway greenhouse effect with surface temperatures hot enough to melt lead, the atmosphere of Earth creates habitable temperatures, and the thin atmosphere of Mars causes a minimal greenhouse effect.
The use of the term runaway greenhouse effect to describe the effect as it occurs on Venus emphasises the interaction of the greenhouse effect with other processes in feedback cycles. Venus is sufficiently strongly heated by the Sun that water is vaporised and so carbon dioxide is not reabsorbed by the planetary crust. As a result, the greenhouse effect has been progressively intensified by positive feedback. On Earth there is a substantial hydrosphere and biosphere which respond to higher temperatures by recycling atmospheric carbon more quickly (in geologic terms; the timescale for the ocean/biosphere to remove a CO2 perturbation is on the order of several hundred years). The presence of liquid water thus limits the increase in the greenhouse effect through negative feedback. This state of affairs is expected to persist for at least hundreds of millions of years, but, ultimately, the warming of an aging Sun will overwhelm this regulatory effect.
The average surface temperature would be -18°C without a greenhouse effect or 72°C with just the greenhouse effect and no convection, but in reality this temperature is closer to 15°C due to convective flow of heat energy within the atmosphere and partly above much of the thermal IR absorbence of the atmosphere. [2]
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The greenhouse gases
Water vapor (H2O) causes about 60% of Earth’s naturally-occurring greenhouse effect. Other gases influencing the effect include carbon dioxide (CO2) (about 26%), methane (CH4), nitrous oxide (N2O) and ozone (O3) (about 8%). Collectively, these gases are known as greenhouse gases. The greenhouse effect due to carbon dioxide is specifically known as the Callendar effect.
The wavelengths of light that a gas absorbs can be modelled with quantum mechanics based on molecular properties of the different gas molecules. It so happens that heteronuclear diatomic molecules and tri- (and more) atomic gases absorb at infrared wavelengths but homonuclear diatomic molecules do not absorb infrared light. This is why H2O and CO2 are greenhouse gases but the major atmospheric constituents (N2 and O2) are not.
Between the absorptions of water vapor and those of carbon dioxide, there is an atmospheric window where, prior to the industrial era, no infrared radiation was trapped, lying between 8 and 15 micrometres. Compounds such as perflurocarbons (CF4, C2F6 etc.), chlorofluorocarbons, halons and SF6 absorb very strongly in this window. This means that they are extremely potent greenhouse gases, especially given the absence of natural sinks to remove them. Perfluorocarbons can have a lifetime of 50,000 years, possibly longer.
Phil,
I posed the question in the first place, so the ball is in your court.
Now I see it is back in mine, with the label, “I have no idea because I do not understand climate, never have, but am easily swayed by the specious arguments of my heroes”.
Well Phil, I have offered one explanation, on the web, and now you are given the task of finding it.
Phil
H2O under earthly temperatures and pressures is a liquid, not a gas.
H2O is a liquid between ) degrees Celsius and 100 Degrees Celsius.
The earth’s surface temperature is at the lower end of this temperature range.
You have no scientific understanding at all of the topic which you wish to impress us with.
Thirdly, gases in an open system cannot trap anything.
You, as most Greenies, simply don’t understand what a Greenhouse is.
Nice duck Louis – from your mention of oxygen and CO2 in the one muddled sentence I see you have no idea about the different with which certain wavelengths of radiation excite certain atmospheric gases. You are bereft of any scientific input on the matter. Therefore I am starting to believe you know a lot less than I’d given you credit for.
So what critical part of the above greenhouse 101 would you like to say is incorrect ?
Phil – it would be salient to remember at this point that if Einstein spent a year explaining Special Relativity to a group of monkeys in the end they would still be monkeys.
I have been through all this many many times with Loius and it still comes back to the same.
Sigh …
Water vapour, also aqueous vapour, is the gas phase of water. On the Earth, water vapour is one state of the water cycle within the hydrosphere. Water vapour can be produced from the evaporation of liquid water or from the sublimation of ice. Under normal atmospheric conditions, water vapour is continuously evaporating and condensing. Normally, water vapour is invisible to the naked eye.
And I don’t think I’m a greenie. Given I support a pro-AGW position and refute your silly position make me a greenie.