# Two questions about Global Warming (one is about the properties of water) **URL:** \ **Category:** Factual Questions\ **Created:** [November 13, 2004, 11:08am UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557 "2004-11-13T11:08:41Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Cisco](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Cisco](https://boards.straightdope.com/u/Cisco)\ **Post date:** [November 13, 2004, 11:08am UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/1 "2004-11-13T11:08:41Z")
Please note that these questions have NO political motivation behind them. I am not a “Global Warming denier”, a Republican, a Democrat, or even a Canadian. I’m asking these questions purely out of curiosity. Now then…Question the first: I was reading an essay about global warming today and the guy kept going on and on about the temperature rising by “as much as 4 degrees” over the next century. I’ve been hearing this for years and I gotta admit, it kind of makes me scratch my head. If I go outside and it’s 94 degrees, and then I walk outside again later and it’s 98, the world hasn’t changed. The birds are singing, the Panthers still suck, and I likely don’t even feel the difference. What are the dangers of the temperature rising a few degrees? Second question, same essay. The guy was also talking about how the ocean levels were rising because “everyone knows that warm water takes up more space.” Hmm, I didn’t know that. Neat fact if true, but I’ve **never** heard that before. What’s the dope? ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [November 13, 2004, 11:19am UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/2 "2004-11-13T11:19:29Z")
It’s nothing to do with expansion of water. It’s the ice caps. Four degrees across the arctic and antarctic means a _lot_ of ice melting, hence rising sea levels. The other important factor is weather patterns. A small change across the planet could easily disrupt ocean flows, such as the Gulf Stream (Madrid’s on a similar latitude to Toronto, and it’s only the warm air from that ocean pattern that prevents similar local weather). Now this may not seem _that_ big a deal, but imagine if the monsoons across Asia were disrupted. Or simply stopped falling. Forever. Literally billions of people would have their livelihoods destroyed. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 13, 2004, 11:46am UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/3 "2004-11-13T11:46:34Z")
Hey, what’s wrong with being a Canadian? I don’t think _small_ changes are globally destructive (or if they were, then we’d’ve been wiped out thousands of years ago) but a jump in global temperatures of four degrees _that didn’t go away_ could create major hassles like serious coastal flooding. It would generally make life for some humans a serious pain in the ass, thus creating disruptions in food production (possibly creating famines), travel, shipping and general economic headaches that delay the futuristicky flying-car utopia promised us in all those 1930s pulp fiction magazines. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [November 13, 2004, 12:09pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/4 "2004-11-13T12:09:39Z")
Actually Ice takes up more space the water, it’s less dense, therefore larger for a given amount of water. Water is most dense at IIRC 4C, as water heats up it does expand, though this may be very small, OTOH the ocean in very large, so it may make a difference. Also note that the N. Pole ice cap is for the most part free floating, so the whole thing can turn to liquid tomorrow and the oceans wouldn’t rise a micron. The S Pole ice cap is on land and if melted would rase the ocean level. But there may be other factors, such as the runoff could disrrupt worldwide ocean currents, I’ve heard a claim of a gulf stream disruption, but again the N pole can’t (for the most part) contrubute to this, so that claim is a bit dubious. The possibility does exist at the S pole ice cap however. ---
**Author:** ![Tabby\_Cat](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Tabby\_Cat](https://boards.straightdope.com/u/Tabby_Cat)\ **Post date:** [November 13, 2004, 12:36pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/5 "2004-11-13T12:36:37Z")
Could the El Nino/La Nina effect be triggered more often by global warming? I remember the rain patterns in Aisa were quite severely affected by them… ---
**Author:** ![Planet\_of\_the\_Shapes](https://avatars.discourse-cdn.com/v4/letter/p/b77776/32.png) [@Planet\_of\_the\_Shapes](https://boards.straightdope.com/u/Planet_of_the_Shapes)\ **Post date:** [November 13, 2004, 12:44pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/6 "2004-11-13T12:44:58Z")
> [@kanicbird](#): > > But there may be other factors, such as the runoff could disrrupt worldwide ocean currents, I’ve heard a claim of a gulf stream disruption, but again the N pole can’t (for the most part) contrubute to this, so that claim is a bit dubious. The possibility does exist at the S pole ice cap however. I was under the impression that the north ice cap melting would send a lot of cold water southwards, and this movement of cold water is what would shut off the gulf stream. Hence the prediction that global warming could actually make North and West Europe colder. Was i incorrect? I thought this was a pretty widely accepted view. ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [November 13, 2004, 12:46pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/7 "2004-11-13T12:46:40Z")
> [@Tabby\_Cat](#): > > Could the El Nino/La Nina effect be triggered more often by global warming? That’s exactly the kind of thing that _could_ happen. The biggest problem is that we have absolutely no way of predicting what are the likely outcomes. We’ve nothing to base any hypotheses on. (BTW, thanks for correcting me on the arctic’s role…I was getting tangled up, with the melt of the arctic being easier to _measure_ than that of the south and therefore easier to use as an indicator of what’s happening.) ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [November 13, 2004, 12:50pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/8 "2004-11-13T12:50:40Z")
> [@Planet of the Shapes](#): > > I was under the impression that the north ice cap melting would send a lot of cold water southwards, and this movement of cold water is what would shut off the gulf stream. Hence the prediction that global warming could actually make North and West Europe colder. Was i incorrect? I thought this was a pretty widely accepted view. It’s more complex than that - the melting ice cap could decrease the salinity of the north Atlantic, and it’s the salinity (and therefore the density) that causes the water to sink and draw less dense water from further south. But it’s all fairly speculative (see my previous comment!) ---
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [November 13, 2004, 2:12pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/9 "2004-11-13T14:12:30Z")
I would assume that after the Antarctic, the Greenland Icecap is probably the largest mass of ice in the world…in places, it is 2 miles thick! Assumimg that the summer temperatures of the arctic were to rise to above 32 f, how many millenia would it take for this whole thing to melt? Also, wouldit flow into the Atlantic Ocean? Or would it form a big lake in the center of Greenland? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 13, 2004, 2:32pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/10 "2004-11-13T14:32:10Z")
> [@GorillaMan](#): > > It’s nothing to do with expansion of water. It’s the ice caps. Four degrees across the arctic and antarctic means a _lot_ of ice melting, hence rising sea levels. Thermal expansion of the oceans is a quite important component of global sea level rise. Warm water is less dense than cold water (above 4 C) and so takes up more space. As the oceans warm, they expand, and sea level rises. This [NASA site](http://gcmd.gsfc.nasa.gov/Resources/Learning/sealevel.html) gives a basic description: > [@](#): > > The Intergovernmental Panel on Climate Change (IPCC) has estimated that the global average sea level has risen 10 to 25 cm (4 to 10 inches) in the past century. > > . . . > > Much of the rise in sea level has been due to the rise in global temperature associated with the global warming of the past century. This type of sea level rise is known as eustatic sea level rise. As the global temperature increases, the ocean water expands. This is also known as thermal expansion of the ocean water. The IPCC has estimated that thermal expansion has contributed 2 to 7 cm (1 to 3 inches) to the total sea-level rise over the past century. In other words about one-fourth to one-third of the total rise has been due to thermal expansion rather than melting of ice. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [November 13, 2004, 2:32pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/11 "2004-11-13T14:32:46Z")
In addition to Greenland, northern Russia and northern Canada have a tremendous land area under permanent ice. All that area will be melting more than it does now too. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [November 13, 2004, 3:27pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/12 "2004-11-13T15:27:13Z")
Going back to the OP’s 4 degrees, that’s probably the annual average. And 4 degrees Farenheit is very different from 4 degrees Celcius/Kelvin. What this means is that spring will start earlier and winter later; over time there will be less ice and the albedo of the Earth will drop, allowing the Earth to absorb more heat… But is it really happenning, is humanity having any significant impact, and can humanity reverse it if it is happenning? I suggest you read The Skeptical Environmentalist. You may not agree with it, but it will make you think. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 13, 2004, 4:13pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/13 "2004-11-13T16:13:14Z")
> [@Quartz](#): > > But is it really happenning, is humanity having any significant impact, and can humanity reverse it if it is happenning? There is a very strong scientific consensus at present that the answers to the first two questions are 1) yes and 2) yes. As to the third, we don’t know - processes may already have been set in motion that would be difficult to stop. However, if nothing is done changes are likely to accelerate. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [November 13, 2004, 4:50pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/14 "2004-11-13T16:50:06Z")
I watched a rebroadcast of _The Daily Show_, and there was someone trying to put a positive spin on Global Warming. He said that global warming would open a new shipping route in Russia. John Stewart quipped [paraphrasing], ‘Just what we need, a way to get our Russian nesting dolls _faster_.’ ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 13, 2004, 5:26pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/15 "2004-11-13T17:26:14Z")
> [@Johnny L.A.](#): > > I watched a rebroadcast of _The Daily Show_, and there was someone trying to put a positive spin on Global Warming. He said that global warming would open a new shipping route in Russia. John Stewart quipped [paraphrasing], ‘Just what we need, a way to get our Russian nesting dolls _faster_.’ I thought this report was particularly ironic: [Global warming to expose Arctic to oil, gas drilling](http://www.alertnet.org/thenews/newsdesk/N08463342.htm) Just what we need - global warming allowing better access to fossil fuels so we can burn them and produce even more global warming. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 13, 2004, 5:43pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/16 "2004-11-13T17:43:38Z")
> [@Cisco](#): > > Now then…Question the first: I was reading an essay about global warming today and the guy kept going on and on about the temperature rising by “as much as 4 degrees” over the next century. I’ve been hearing this for years and I gotta admit, it kind of makes me scratch my head. If I go outside and it’s 94 degrees, and then I walk outside again later and it’s 98, the world hasn’t changed. The birds are singing, the Panthers still suck, and I likely don’t even feel the difference. What are the dangers of the temperature rising a few degrees? The upper range for the increase in average global temperture for the next century is about 4 C (not 4 F), equivalent to about 7 F. As others have mentioned, the actual impact on local climate of an average rise of this magnitude will be very complex, and will depend on changes in weather circulation, ocean currents and many other factors. This said, a change in average annual temperature of 7 F is approximately equivalent to the difference between the climates of New York City and North Carolina. In effect, in many areas (but by no means all) the climatic zones would move a couple hundred miles northward. While this could be pleasant in some places with a cold climate, it would cause, among other things, a massive disruption of agriculture. Farmers would have to change their entire systems of agriculture to accomodate crops adapted to a different climatic zone – and this isn’t even considering likely changes in the amount of rainfall and its seasonality. > [@Tabby\_CAt](#): > > ]Could the El Nino/La Nina effect be triggered more often by global warming? I remember the rain patterns in Aisa were quite severely affected by them… There has been some speculation that that could happen, but as far as I am aware there is no definitive evidence for it as yet. ---
**Author:** ![DanBlather](https://avatars.discourse-cdn.com/v4/letter/d/f4b2a3/32.png) [@DanBlather](https://boards.straightdope.com/u/DanBlather)\ **Post date:** [November 13, 2004, 6:14pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/17 "2004-11-13T18:14:52Z")
Lots of good posts. As for “only” a 4 degree difference, that is huge if it means that precipitation that used to fall as snow now falls as rain, or that glaciers begin to recede. I used to be a skeptic on global warming, but there now seems to be overwhelming evidence for it. I took a cruise to Alaska last summer and some of the glaciers are miles shorter than they were in the 1800s. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [November 13, 2004, 6:27pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/18 "2004-11-13T18:27:45Z")
> [@DanBlather](#): > > Lots of good posts. As for “only” a 4 degree difference, that is huge if it means that precipitation that used to fall as snow now falls as rain, or that glaciers begin to recede. Indeed. There were some concerns last year about the lack of snowfall in this area. Snow is sort of a ‘water bank account’. Water is stored in the snow pack in the Winter, and released throughout the year. This water is used to irrigate crops, quench the thirst of populations, provide paths for migrating fish, and to create electrical power among other things. Some water that falls as rain is absorbed into the ground to replenish aquifers. Much of it just flows into the oceans. A large amount of rain can cause floods that destroy natural and man-made habitats, and then the areas can become arid during the dry season. In the bank account analogy, it’s like getting your annual salary at the beginning of the year. You can store it in the bank and draw funds as needed, or you can go on a spending spree and not have anything left for the rest of the year. What do you do then? So it is with snow. Our water funds can be stored for use throughout the year, or we can liquidate the account and spend or waste it. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [November 13, 2004, 7:31pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/19 "2004-11-13T19:31:39Z")
> [@Colibri](#): > > There is a very strong scientific consensus at present that the answers to the first two questions are 1) yes and 2) yes. The problem is that scientists have a bit of a tarnished reputation. Global Warming is a Politically Correct theory, and people are afraid to stand up and present contrary views - look at what happenned to Lomborg. And, of course, it’s a terrific money-spinner. ‘Our research indicates that further tests are required …’ Lomborg, of course, may be drawing entirely the wrong conclusions, but people need to draw their own conclusions. Just the other week, there was a natural history program on the BBC showing that London was once a place inhabited by lions and hippos - i.e. tropical warmth in the quite recent past - a previous interglacial. And we’ve only just come out of the Little Ice Age, so we may well be still warming naturally. Global climate change may be the norm. Who knows? It’s a fascinating subject. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 13, 2004, 8:50pm UTC](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557/20 "2004-11-13T20:50:33Z")
> [@Quartz](#): > > The problem is that scientists have a bit of a tarnished reputation. Global Warming is a Politically Correct theory, and people are afraid to stand up and present contrary views - look at what happenned to Lomborg. Utter rubbish. Spoken like someone who has no understanding of scientists or the way science works. The best way to make your name in science is to advance contrarian views - _as long as you have the evidence to back them up_. Evidence for global warming, and the fact that a significant part of it is due to human impacts, is sufficiently strong at this point that it has been [accepted even by the Bush administration](http://whyfiles.org/updates/080global_warm/). It’s hardly “politically correct” any more, if it ever was. > [@](#): > > And, of course, it’s a terrific money-spinner. ‘Our research indicates that further tests are required …’ Do you really think a scientist whose research suggested that global warming wasn’t occurring would have much trouble obtaining funding from energy companies? > [@](#): > > Lomborg, of course, may be drawing entirely the wrong conclusions, but people need to draw their own conclusions. > > Just the other week, there was a natural history program on the BBC showing that London was once a place inhabited by lions and hippos - i.e. tropical warmth in the quite recent past - a previous interglacial. And we’ve only just come out of the Little Ice Age, so we may well be still warming naturally. > > Global climate change may be the norm. Who knows? It’s a fascinating subject. You are obviously “drawing your own conclusions” from an extremely superficial understanding of the issues involved and of the data on which scientists have based their conclusions. I would suggest that you actually do some in-depth reading on the subject before making statements like “Who knows?” There have been any number of threads on this subject in Great Debates. It would be worth your while to read some of them. [Next page](https://boards.straightdope.com/t/two-questions-about-global-warming-one-is-about-the-properties-of-water/274557.md?page=2)