Could "Global Warming" Actually Be Good For Mankind?

[BrainGlutton]

If the sea level were to rise 300 feet, I guess that would submerge a lot of coastal cities. (Submerge the streets, anyway, while leaving exposed the upper floors of the buildings – just like the New York scenes in A.I.!) But how fast would it happen? I mean, we wouldn’t just wake up one morning and see the streets flooded. There would be a slow, creeping rise in the water level. But would it take months, or years, or decades, or centuries, to go from the present level to 300 feet higher?

[hansel]

Quick hijack: if the polar caps melted, why would the sea level rise? Doesn’t the ice currently in the water displace more volume than would be replaced by that ice in liquid form?

[Asteroide]

Hansel This problem is just the tip of the iceberg…

[YourOldBuddy]

Just a note on the Viking colonization of Greenland. Greenland was a marketing turn by Eric the Red who first settled there because of his outlaw status in Iceland (manslaughter). He didnt want to be alone over there so he named the place Greenland, so the name is really a marketing-term as opposed to the name Iceland coined by a viking who lost all his lifestock due to greed and hated the place. No one really knows what happened to the settlements in Greenland but Inuits in Greenland have a lot of Viking genes in them primarily from male vikings. All contact was lost in the 14th century and it is thought that the vikings mostly moved away due to lack of market in Europe for fur and Ivory. Also added taxation from Norway and declining wheather made the place less palatable.

Leif the lucky son of Eric the Red was probably the first European to reach mainland America. After skirmishes with the locals they retreated to Iceland and Greenland.

[BrainGlutton]

The Arctic icecap is mostly submerged already, so I guess its melting wouldn’t raise the sea level – no more than the level of water in a glass rises when the ice cubes melt. But the Antarctic icecap is a massive, thick ice shield on top of a continent-sized land mass. If it melted, the water would run downhill into the ocean, and it would make a difference, I think. But how much frozen water there is on top of Antarctica, and how much it would come to if spread over the surface of the whole world-ocean, I do not know. TWOTfan gave a figure of 300 feet for the rise in sea level that would result from the icecaps melting, but gave no cite. Milum stated, “Best measure is a - 375 feet drop of sea level at the height of the last glacial period.” Again, no cite. Fine, but we’re in an interglacial period, i.e., a warm period, already. If it gets even warmer, would that make a big difference? Most of the ice that was locked up in glaciers in the last Ice Age has already melted.

Here’s a good earth-science question: As I understand it, Antarctica has remained frozen solid through multiple ice ages and interglacials going back millions of years. So when was the last time Antarctica was warm? Has it been covered by an ice shield ever since the continent migrated to the South Pole?

[hansel]

*Originally posted by Asteroide *
**Hansel This problem is just the tip of the iceberg… **

HAR HAR HAR!

No, seriously.

[jshore]

*Originally posted by Bookkeeper *
If you look at climate in the long term, the Earth has almost always been significantly warmer than it is today. We are in a period of on-again off-again glaciation at the moment, and temperature swings are part of this.

I find most of the evidence for global warming to be less than convincing, and in many cases apparently produced by data picking (look around until you find some bit of data that supports your position, and ignore the rest). Temperature trends over the last 50 or 100 years are meaningless, as this is far too short a period to provide a significant baseline for climate change. IIRC, we still have a ways to go before we even reach the average temperatures of the ~800-1400 A.D. warm period which let the Vikings colonize Greenland, and this was hardly an environmental disaster, as it was a period of good harvests and growing prosperity for most of Europe at least.

Your statements are completely at odds with the current state of the peer-reviewed climate science literature. Here is a quote from one of the IPCC Third Assessment Report (IPPC TAR) technical summaries (see www.ipcc.ch ):

It is likely that the rate and duration of the warming of the 20th century is larger than any other time during the last 1,000 years. The 1990s are likely to have been the warmest decade of the millennium in the Northern Hemisphere, and 1998 is likely to have been the warmest year. There has been a considerable advance in understanding of temperature change that occurred over the last millennium, especially from the synthesis of individual temperature reconstructions. This new detailed temperature record for the Northern Hemisphere is shown in Figure 5. The data show a relatively warm period associated with the 11th to 14th centuries and a relatively cool period associated with the 15th to 19th centuries in the Northern Hemisphere. However, evidence does not support these “Medieval Warm Period” and “Little Ice Age” periods, respectively, as being globally synchronous. As Figure 5 indicates, the rate and duration of warming of the Northern Hemisphere in the 20th century appears to have been unprecedented during the millennium, and it cannot simply be considered as a recovery from the “Little Ice Age” of the 15th to 19th centuries. These analyses are complemented by sensitivity analysis of the spatial representativeness of available palaeoclimatic data, indicating that the warmth of the recent decade is outside the 95% confidence interval of temperature uncertainty, even during the warmest periods of the last millennium.

There has been a small vocal (with voices magnified by conservative/libertarian think-tanks and some of the fossil fuels industry) minority who have tried to argue that there was a worldwide Midieval warm period and recently Willie Soon and Sallie Baliunas did manage to get a paper published in a peer-reviewed journal arguing this. However, this is but one paper…and it is a paper that both the editor-in-chief and publisher of that journal now admit has major flaws that shouldn’t have allowed its publication, at least in the form in which it appeared. (After this whole fiasco, the editor-in-chief in fact resigned over a disagreement with the publisher on the way the peer-review & editorial process was being handled. The publisher, while defending the general process, admitted there had been a failure in this case.)

[jshore]

*Originally posted by BrainGlutton *
If the sea level were to rise 300 feet, I guess that would submerge a lot of coastal cities. (Submerge the streets, anyway, while leaving exposed the upper floors of the buildings – just like the New York scenes in A.I.!) But how fast would it happen? I mean, we wouldn’t just wake up one morning and see the streets flooded. There would be a slow, creeping rise in the water level. But would it take months, or years, or decades, or centuries, to go from the present level to 300 feet higher?

Certainly, it would not be an overnight thing. And, by the way, I should point out that the 300 feet number, which would surely be a gargantuan disaster, is way higher than the best estimates of what sea level rises would be in the next 100 years with global warming. I forget what the estimates are but they are much smaller…In fact, they might at first sound insignificantly small. But, it turns out that it doesn’t take very much rise in height to flood a lot of land, especially inhabited land.

[BrainGlutton]

Well, here’s something at least a little bit authoritative – the Encarta article on Antarctica (http://encarta.msn.com/encyclopedia_761565002/Antarctica.html):

The total volume of the ice sheet covering Antarctica is estimated to be 29 million cu km (7 million cu mi), or about 90 percent of the world’s ice. If the ice sheet melted, the oceans of the world would rise by 60 m (200 ft). Some 11 percent of the ice sheet consists of ice shelves—massive floating slabs of permanent ice fringing the continent—that are anchored to the rock and extend into the surrounding ocean. The largest, Ross Ice Shelf, is about the size of France. The Antarctic ice sheet has an average thickness of 2,160 m (7,090 ft); its greatest recorded depth is more than 4,700 m (15,400 ft).

<snip>

During the Mesozoic Era (about 240 million to 65 million years ago) Antarctica was a central part of Gondwanaland, an ancient landmass that consisted of the present continents of South America, Africa, Antarctica, and Australia as well as the Indian subcontinent. Evidence from oceanic ridges surrounding Antarctica indicates that Gondwanaland began to break up about 150 million years ago. Antarctica gradually drifted towards the South Pole, arriving near its present polar position about 100 million years ago. Climatic cooling caused the gradual formation of the Antarctic ice sheet.

So, Antarctica has been at the South Pole, covered by an ice sheet, for about 100 million years. When the dinosaurs roamed the earth, they didn’t roam Antarctica, which was far away and frozen solid. And if all the Antarctic ice melted, the sea level would rise by 200 feet. But the article doesn’t say if any substantial part of the Antarctic ice shield ever has melted, during any of the warmer periods over the past 100 million years.

There is some relevant info in the Encarta article on Ice Ages (http://encarta.msn.com/encyclopedia_761570002/Ice_Ages.html):

Tillites from Ontario and elsewhere in North America may have been formed from the same glaciation that deposited tillites in South Africa and possibly Australia. These tillites are evidence of one of the first ice ages, which occurred more than 950 million years ago. The next ice age occurred between 950 and 600 million years ago, and included at least three separate glacial-interglacial intervals. These continental glaciations were widespread and included western North America and portions of South America, Africa, and Australia. Another expansion of continental ice, between 450 and 400 million years ago, was centered in northern Africa and spread to adjacent portions of northern Europe and South America. Between 330 and 240 million years ago, an extensive glaciation affected Africa, Antarctica, Australia, Asia, and South America. Despite evidence for the widespread distribution of this particular glaciation, smaller, localized icecaps were probably more common than massive continental ice sheets. This is because during this time sea level fluctuated only slightly, rather than the 130 m (430 ft) or more of fluctuation that would be expected if great volumes of ice alternately formed and melted.

B Future Ice Ages

The record of previous glacial activity is the best indicator for future ice ages. Scientists examine the evidence for the numerous 100,000-year glacial-interglacial cycles within the present ice age to attempt a forecast of future ice ages. Since all previous ice ages lasted tens of millions of years, our present ice age will likely continue for a considerable amount of time. Each glaciation begins slowly and may take 80,000 years or more to reach its maximum extent. A rapid melting of these expanded glaciers within just a few thousand years follows. Then the next glaciation begins to build, only 10,000 to 20,000 years after the maximum of the previous glaciation occurred.

Evidence from both land and sea environments indicates that, at least prior to the human-induced global warming of the last two centuries, the worldwide climate has been cooling naturally for several thousand years. Ten thousand years have already passed since the end of the last glaciation, and 18,000 years have passed since the last maximum. This may indicate that Earth has entered the beginning of the next worldwide glaciation.

So we’re due for another ice age – which won’t reach its peak for another 80,000 years or so. No worries. Plenty of time to adjust, shop for winter coats, and build weatherproof space colonies to keep the human race going Just In Case. And in the past, the glacial-interglacial cycle has caused only minor fluctuations in the sea level – nothing to worry about there.

But what happens when anthropogenic “global warming” becomes an added factor in this cycle? How can we know? There are no precedents in the earth’s history – unless we count natural phenomena such as the comet that supposedly wiped out the dinosaurs. (Did that comet cause “global warming”?)

[Asteroide]

Although rising sea- level would probably be a gradual process, currents and weather patterns could change in an instant (or self-stabilize forever:) )

Even a relatively minor change in eg the Gulf Stream could profoundly affect the weather patterns of some densely populated regions. Ice melt could cause this. On the other hand no two models seem to agree on the outcome - let’s face it, weather forecasting is a tricky business.

Specifically regarding sea-level, ice melt would not be the only factor - water expands as temperature rises.

[jshore]

*Originally posted by eburacum45 *
Because of the long term decline in the level of CO2, down from values which were ten times today’s back in the Mesozoic, the Earth is likely to get increasingly cold over the next ten million years;

By the way, while it may be true that CO2 levels are down from long ago, they are believed to be higher than they’ve been on any human timescale. Here, again, is a quote from the IPCC TAR technical summary:

The atmospheric concentration of CO2 has increased from 280 ppm in 1750 to 367 ppm in 1999 (31%, Table 1). Today’s CO2 concentration has not been exceeded during the past 420,000 years and likely not during the past 20 million years. The rate of increase over the past century is unprecedented, at least during the past 20,000 years (Figure 10). The CO2 isotopic composition and the observed decrease in Oxygen (O2) demonstrates that the observed increase in CO2 is predominately due to the oxidation of organic carbon by fossil-fuel combustion and deforestation. An expanding set of palaeo-atmospheric data from air trapped in ice over hundreds of millennia provide a context for the increase in CO2 concentrations during the Industrial Era (Figure 10). Compared to the relatively stable CO2 concentrations (280 ± 10 ppm) of the preceding several thousand years, the increase during the Industrial Era is dramatic. The average rate of increase since 1980 is 0.4%/yr. The increase is a
consequence of CO2 emissions. Most of the emissions during the past 20 years are due to fossil fuel burning, the rest (10 to 30%) is predominantly due to land-use change, especially deforestation. As shown in Figure 9, CO2 is the dominant human-influenced greenhouse gas, with a current radiative forcing of 1.46 Wm−2, being 60% of the total from the changes in concentrations of all of the long-lived and globally mixed greenhouse gases.

*Originally posted by SPOOFE * The planet’s ecosystem is remarkably self-correcting… things get too hot, that means more water evaporating, which means greater snowfall in the northern regions, which means more cold, which means less water evaporating… etc.

This is a common fallacy to believe that the feedback effects will be negative. Actually, in nonlinear systems, feedbacks can often be positive, causing the system to undergo some dramatic shifts. And, in fact, most people in the climate science field believe that the water vapor effect is positive. Again, the IPCC report:

A major feedback accounting for the large warming predicted by climate models in response to an increase in CO2 is the increase in atmospheric water vapour.

And, finally, another point that I meant to include in my response to Bookkeeper: One of the interesting thing about your beliefs is how out of line they are not only with what is generally believed in the climate science community, but even what is believed by some major fossil fuel companies, BP and Shell being two notable ones that now acknowledge the need to be concerned about anthropogenic climate change. (BP in fact endorses the Kyoto Protocol and has implemented Kyoto-like reductions in their own greenhouse gas emissions, reaching their goal 8 years early and a a claimed net monetary savings.)

[rjung]

*Originally posted by hansel *
Quick hijack: if the polar caps melted, why would the sea level rise? Doesn’t the ice currently in the water displace more volume than would be replaced by that ice in liquid form?

Just in case you didn’t get your question answered already…

The answer is, no, if the polar caps melted, the sea levels would rise. Don’t think of the polar caps as a couple of giant ice cubes floating in the ocean; rather, think of them as islands at the poles that are covered with a thick sheet of ice. If the caps melted, the water from the ice would run into the ocean, exposing the land underneath – and raise the sea levels.

This is a bit of an oversimplification, but it’s a lot more accurate than the “ice cubes in water” theory (usually espoused by clueless news commentators). This is especially accurate for Antarctica, which is why scientists are very concerned with the hole in the ozone layer down there…

[jshore]

Okay, it took me a few posts to finally make it back to the main topic of the OP. I think there has been a good explanation already about how change by its very nature would tend to have more negative than positive effects. The “Impacts, Adaptation, and Vulnerability” part of the IPCC TAR report talks, presumably in quite a bit of detail, about all the possible negative and positive effects. I must admit that I haven’t read that much of this part but here is a link to the PDF file Summary for Policymakers for that section of the TAR about consequences of warming. [My cut-and-paste from Acrobat Reader has inexplicitly stopped working so I won’t attempt to paste quotes in, but I refer people in particular to Sections 2.3-2.8 therein. If I have time later…and can get the cut-and-paste working, I’ll try to post some of the highlights.]

[BrainGlutton]

Posted by rjung:

Don’t think of the polar caps as a couple of giant ice cubes floating in the ocean; rather, think of them as islands at the poles that are covered with a thick sheet of ice. If the caps melted, the water from the ice would run into the ocean, exposing the land underneath – and raise the sea levels.

The South polar icecap is on top of a land mass. The North polar icecap is, in fact, a giant ice cube – not exectly “floating” in the ocean, I believe, as the water underneath it is frozen solid all the way down to the sea bed – am I right? But there’s no “island” under it, only the sea bed, which is at the same depth as elsewhere in the Arctic Ocean, based on sea-floor relief maps I’ve seen. So if the North icecap melted, it would be more like an ice cube melting in a glass of water.

Posted by Asteroide:

Specifically regarding sea-level, ice melt would not be the only factor - water expands as temperature rises.

Thanks, I had forgotten about that. But, again, how much does the water expand when the earth warms?

Let me put it another way. If anybody knows: What is the highest the sea level has ever been since the Mesozoic? Compared with its present level, I mean.

[eburacum45]

The North pole ice cap doesn’t extend to the bottom of the sea, as the USS Nautilus was able to prove by navigating under the pole in 1958.

If the north pole floating ice melted it would not affect the sea level at all.

However if you melted all the land based ice it would raise the sea level by 70-80 metres; it isn’t really relevant to ask how high the sea level has been in the past, as the continents have all moved and changed shape since the ice on Antarctica first formed.

For the record, jshore is right; CO2 is currently on the increase, and this is due to anthropogenic production of CO2.
This shows that humanity can affect the atmosphere on a global scale;

what we need to do is control it.

oh and as a nitpick, global warming per se is indispensible for the continued existence of mankind; without the warming insulation of an atmosphere, the Earth would be as inhospitable as the Moon.

---

SF worldbuilding at
http://www.orionsarm.com/main.html

[Marley23]

To get back to the OP for a moment, only because I’m not at all a climatology expert: global warming seems to me to be associated with increasingly erratic weather. Of course, the weather is hard to predict and erratic anyway, but if global warming makes this worse, that’s a bad thing. Some places in the world are getting colder. It’s not as if, if we get enough CO2 into the ozone, one day everyplace will be 72 degrees and sunny like San Diego.

[jshore]

*Originally posted by eburacum45 *
oh and as a nitpick, global warming per se is indispensible for the continued existence of mankind; without the warming insulation of an atmosphere, the Earth would be as inhospitable as the Moon.

Point taken. Indeed, it is the anthropogenic global warming that we are concerned about, i.e., the additional radiative forcing we are putting on the climate system by increasing the concentrations of various greenhouse gases like CO2 and methane in the atmosphere.

[cowgirl]

“Global warming” is a bad name for two reasons: one, it’s not accurate, since in a lot of places cooling will occur, and a lot of times it means more extreme weather events, etc. Two, it facilitates lines of reasoning like the one suggested by the OP: “Hey, I like warmth! So won’t it be good for the globe to get warmer?”

“Climate change” has been accepted usage for quite a while, but I prefer “climate destabilization” since that really emphasizes the instability and other nastiness that it could entail.

[rjung]

*Originally posted by BrainGlutton *
The South polar icecap is on top of a land mass. The North polar icecap is, in fact, a giant ice cube – not exectly “floating” in the ocean, I believe, as the water underneath it is frozen solid all the way down to the sea bed – am I right? But there’s no “island” under it, only the sea bed, which is at the same depth as elsewhere in the Arctic Ocean, based on sea-floor relief maps I’ve seen.

Yeah, I know – I was simplifying the answer. But then, I get my idea of “how to teach science” from Beakman’s World.

[jshore]

*Originally posted by Bookkeeper *
Current climatological science seems to go against the main thrust of the Kyoto Agreement, as it shows CO2 increases lagging warmer periods in the past, rather than preceeding them, indicating that increased CO2 is a result of warming rather than a cause of it.

I avoided responding to this until I had read up a little more on the science behind it. This turns out to be a rather subtle issue … And, in fact, since the temperatures and CO2 concentrations are so closely correlated in time, it is not easy to detect which is leading or lagging which on the time scales one is looking over. (See for example, the graph on this page.)

An important fact to note, however, is that the ideas of global warming are not based on the notion that in the past changes in CO2 were the primary, or particularly the initiating, cause of warming. In fact, without man around to pump large amounts of CO2 in the atmosphere, it is believed that changes in “orbital forcings” were likely the initiating cause of these cycles but that increase in greenhouse gases then caused a positive feedback effect. Or, as it is summarized here:

From a climatic viewpoint, CO2 and CH4 have played an important role. Together with the growth and decay of the Northern Hemisphere ice sheets, these greenhouse gases have amplified the initial orbital forcing, and they account for about half of the glacial-interglacial climate changes. This supports the idea that significant greenhouse warming will occur in the next century.

Or, to quote from the IPCC TAR Working Group I full text (Chapter 3):

The Vostok record of atmospheric CO2 and Antarctic climate is consistent with a view of the climate system in which CO2 concentration changes amplify orbitally-induced climate changes on glacial/inter-glacial time-scales (Shackleton, 2000).

And, finally, getting back to the first source I cited with the graph, here is an extended quote from there. This explanation has the virtue of being one of the most straightforward that I have found in presenting the bottom line of all this although I can’t vouch for the credentials of who is presenting it:

Given all the new ice core data, what changes can we anticipate for our climate? If CO2 has increased over the past 150 years as much as it normally increases over thousands of years leading up to an interglacial phase (about 80 ppmv), then we could expect as much as a corresponding 10-12C increase in temperature. But if half the historical temperature increases have been due to orbital forcing and other factors, then we should expect an increase of “only” about 5-6C, or 9-11F.

Most computer models don’t predict either of these magnitudes of temperature change for the new century. They typically cite evidence indicating that overall global temperatures have not changed as much as polar temperatures, where the ice cores were taken, and that increases of only 2-3C should be anticipated. Unfortunately, new evidence from high-elevation tropical ice cores indicates that this is not really the case. The latest data show that the amplitude of sub-polar temperature changes has been in the range of 8-12C, which is not all that different from the 10-12C found at the poles.

Thus we seem to be headed for some very large climate changes. Temperatures could increase rapidly, and then decrease just as rapidly–as they have repeatedly over the past 420,000 years. Another possibility is that there will be so much GTGs in the atmosphere that they will actually override historical patterns of thermohaline circulation and climate change.