Since the Younger-Dryas about 8000 years ago the Earth's climate has been relatively stable. During this time, agriculture was developed and human populations increased from 5 million to 7 billion.. Whether any future climate change is good, bad or indifferent ought to be compared against these 8000 years. About 55 million years ago, the earth was pretty darned hot. 34 mya the antarctic ice sheet began to form. There have been many wide variations in climate over such longer time scales. The main reason I can see for invoking them in a human-based discussion is that we sure don't want to go to the extremes. Either too hot or too cold. And yes, our developing understanding of the earth's climate history was paid for (largely) by somebodys' tax money. A darned good use of money in my opinion.
MAN has a long long history of changing climate via agriculture, chopping down trees, killing big game, etc. It is largely irrelevant what percentile is caused by natural fluctuation and which by androgenic activity. More practical question is what are the implications, and what impact it has down the road.
The point, which the deniers love to gloss over or ignore, is that a tenth of a degree change in average global temperature, which is too small for anyone to notice at home, can have major effects on weather patterns, bringing drought to agricultural areas and rain to places where we have no infrastructure to benefit from it. This can affect global food production. The Earth won't care, and life will go on, but the human race will be impacted in disastrous ways. Of course, it's all just nature adjusting the balance: Too many people --> too much pollution --> alteration in available resources --> population collapse brings the human population back to sustainable levels, say around 100 million. Everyone will be happy except the survivors, who will eventually settle back to a stone-age culture. I sure hope I don't live to see it.
Oh dear, more hand-wringing from the same group promoting the destruction of free market liberties in part through EPA regulation based on a fraud, Climategate 1.0, 2.0, X.0? What's a pious Believer to do having gone from the clear danger of the coming Ice Age to Global Warming to Climate Change and now back to the coming Ice Age? Maybe those gullible enough to be manipulated by the newly created theory of "consensus science" deserve to be sheared. Anyway, no worries, the coming Ice Age will fix rising sea levels. "White House science czar John Holdren has predicted 1 billion people will die in "carbon-dioxide induced famines" in a coming new ice age by 2020." Read more: Holdren: Ice age will kill 1 billion Holdren: Ice age will kill 1 billion "10 reasons to be cheerful about the coming new Ice Age" http://blogs.telegraph.co.uk/news/jamesdelingpole/100092280/10-reasons-to-be-cheerful-about-the-coming-new-ice-age/
To highlight the context of your quote - The world is coming to an end has been long proclaimed. I am hopefull that in the face of warming (or cooling) man will find a way to produce more food. In the last 30 years the famines have been caused by politics not some malthusian plot or warming (or even cooling). Ehrlich unfortunately is still listened to, and warming and population will kill us all, his predication just was early. [note sarcasm] But the climate is changing, anyone with a view to history can see that. Some argue it is all natural, or according to that bad Ehrlich book the warming is stopping the natural cooling. Its hard to believe that chopping down so much forest and burning so much fuel is doing nothing. We should know much more in 20 years. It certainly does not take a consensus, only scientific method to know that if climate change is melting the ice, sea levels will rise and their will be more flooding.
Oh dear, more political hand-wringing from the same group claiming destruction of the free market from the EPA Believe it or not, lobbying efforts from either fossil fuel companies or alternative energy companies are both based on the same markets! The rest of the talking points in this post just show empty rhetoric and no argument against AGW. It's just yet another personal attack on a theory from the 1970s (a faux news article could at least try to address data from this decade!)...and still does not address specific issues on climate. It should be controversial as to what exact contribution anthropogenic polution has on climate: not whether it has any impact (as it's been a majority of scientists and thinking people who have accepted that air polution and deforestation actually does change the environment). But no, wingnuts still have to try to deride and redicule in a political manor instead of actually contributing anything meaningful. It must be blissful to be so insular.
"We should know much more in 20 years." We have know more than enough for at least ten years, if not twenty already. Tick, Tock
"Since 2007 the polar icecaps have been growing not melting and the earth has been cooling, not warming...Should we instead be proposing to outlaw El Ninos or forbid solar eruptions?" Nah, it's so much more profitable to concoct schemes like trading carbon credits and consensus science while fleecing the sheep and flying by private jet to the vacation mansion. And to think only a few years ago our President made a plea in front of the UN to impose fees and taxes to combat Global Warming. Global Warming or Global Freezing: is the ice really melting?
Interesting to see how beliefs are formed on the lack of facts... http://nsidc.org/pubs/annual/NSIDC_Annual_Report_2010.pdf Project Summary NASA - Satellites Show Arctic Literally on Thin Ice [/FONT][/FONT]
you might have missed this: http://priuschat.com/forums/environmental-discussion/93800-antartica-ice-loss-has-accelerated.html and NASA - Is Antarctica Melting? bottom line no, Antarctica is not melting; actually melting had decreased. Unfortunately the ice loss is accelerated. How could both of the statements be true?
In 20 years their should be much more knowledge about if rainfall pattern/warming/cooling driven climate change cause massive crop failures. Every prediction of doom has been wrong, since Malthus. Since kyoto passed it has been a failure in reducing growth in ghg, this was predicted since it did not include china and india. No surprise their except to those in Canada and Europe that said it would do something. You can try to calculate the impact if Canda did not cheat and the US had signed and made a good faith effort, and CO2 levels would not be substantially different today. The GCM were predicting higher temperatures even with reduced ghg, but they may have not taken enough climate variability into account. Climate variability modeling is something more data will provide. AMPED, the artic ice is melting. You can see it on satelite photos, you can measure the sea level rise. You need to take periods of time, not individual months or years. Artic ice has been melting since the little ice age, and ghg are contributing to the melt. GHG levels would have rissen naturally, but man is contributing to current levels. It is not following a doom scenario, but is rising as would be predicted by global tempertures.
AG it is not only Artica the western Antarctica is in the same boat. I am not buying into "sky is falling" doom scenarios, at least short-term, but you have to realize that androgenic GHG contribution had sped things up. We are heating faster then we did perhaps with exception of final phase of PTE and maybe PETM and it cannot be good. CO2 is not the only player; the amount of methane trapped in arctic shell and permafrost and its rapid release renders pretty much all reconstructed climate sensitivity models useless. We can argue 1/2.3/3K for all we want but if permafrost melt doubles it, what good .7K do?
I find speculation on the speed of heating rather unscientific. For amped to understand the science, I would prefer not to do this kind of hand waving. Although Antartica may be losing ice, it is far less than the artic, and there are measures that show it gaining. Again, lets not back into the speculation. The problem with this speculation and doomsday predictions are when they don't come true, people get mad and think the whole thing is one big lie. The huge sea level rise in that inconvient movie seemed to imply it would happen soon. Best estimates of the rise from the 1990s to 2100 is a few millimeters to 2 meters with a likely level around 40cm or 1.5 feet. methane release is included in the GCM, and is part of the feedback. Although methane release is a major source of natural ghg warming, and this is speculated about in the ice cores, it is not currently a major anthropologic factor. If man stopped burning fossil fuel, the methane locked can still be released.
well the final phase of PTE took about 8-12,000 years and resulted in 5C warming, or 0.0417-0.0625C per century. Granted it is avg there had to be spikes with methane belches resulting from ocean floor warming and methane clathrate melt. if you read references provided above it is not the case; per NASA Antarctica is loosing more ice then it is gaining, despite additional snow fall. As about huge sea level rise it is actually funny how believers and deniers alike keep pointing at it. Be that a dooms day or proof that GW doesn't exists. Sometimes you wonder if they ever considered the buoyancy of ice in water and the simple physics of melting on a basic common sense level. Ice is roughly 10/11 density of the water, so ~9% of the floating ice will be above surface, and 91% is under. Melting of ice suspended in ocean will have no effect on ocean level (duh!) as submerged ice displace the same volume as melted water will take and melting ocean floor ice is actually going to decrease sea level. So really you only have to worry about land-bound ice masses. The glaciers do not have much ice to have a considerable impact, so basically only Greenland, East Antarctica and land-bound portion of West Antarctica to be of concern. Problem is not that it will be released; problem is the release rate. Methane is unstable in atmosphere and gets oxygenated quickly. Methane is a positive feed back so warming speeds up methane release and methane release speeds up warming. Since warming has no effect on oxygenation rate, it will results in much higher methane concentration. It is of a concern since methane has x90 short term potency of carbon dioxide.
The OPs article was talked about sea level rise, which is why I commented on it. The exagerated melts are why some people don't look at the science. The rise was about 6" in the last century. You don't need to believe or deny to look at the science and understand that getting a 6 meter rise in a century would require something extrondinarily different. Great belching of methane might get a melt of 2 meters. Even with no warming ice will continue to have a net melt, as it takes time to reach equilibrium. Not quite sure, what ice burg size estimation has to do with rising sea levels, but it also doesn't matter all that much. I'm quite confident those studying the artic and antartic ice masses understand how much floating ice is out there and how fast it will melt.
well, yea, no one wants to miss out on all the benefits of early industrialization (despite the toxic down side) until their up to speed ... like all the other countries got a chance to do.
yes the icebergs don't matter; iceberg melting results in no net gain on see level. Melting of sea floor ice results in 8.3% volume reduction. Well methane clathrate melts at 18C. There is enough of it trapped on ocean floor to destroy all life as we know it many times over. It does not melt b/c the ocean currents (Thermahaline) do not allow top warm and bottom cold water to mix. the danger of arctic ice sheet melting (Greenland) is that Thermahaline may collapse and allow oceans on continental shelves to warm enough to melt clathrates and release methane. It may not happen and if it will it will take way more then our lifetime but do we wanna find out? here is some info on THC: Thermohaline circulation and clathrates: [ame="http://en.wikipedia.org/wiki/Clathrate_gun_hypothesis"]Clathrate gun hypothesis - Wikipedia, the free encyclopedia[/ame]
Arctic ice melting since deglaciation: Yes, but not at a constant rate Fileost-Glacial Sea Level.png - Wikipedia, the free encyclopedia and compare to current rate (2 mm/year) or compare to later-in-21st century projected rate (4 mm/yr) The fastest rate on the referenced graph is about 8 mm/yr