# Explaining global warming **URL:** \ **Category:** In My Humble Opinion\ **Created:** [September 15, 2009, 3:12pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176 "2009-09-15T15:12:40Z")\ **Posts on this page:** 20\ **Page:** 1
**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:** [September 15, 2009, 3:12pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/1 "2009-09-15T15:12:40Z")
How does one explain global warming to people whose understanding of meteorology is limited to technology no greater than a [weather rock](http://en.wikipedia.org/wiki/Weather_Rock)? I have not debated global warming (natural or anthropogenic) with people like this, but their argument against global warming generally runs like this: ‘This is the worst Winter we’ve had since I can remember! So much for “global warming”!’ And they mean it. Is there a way, preferably using single syllables, to explain the interaction of (what appear to be to some people) small rises in the average global temperature, general meteorology, and other factors that result in specific weather in a region? That is, how does one explain that warmer weather in one part of the world will result in colder-than-normal temperatures where they are? ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [September 15, 2009, 4:15pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/2 "2009-09-15T16:15:51Z")
It’s colder this morning than it was yesterday afternoon, ergo, the Earth is cooling down! Try to get them to switch off the term “global warming” and to “climate change.” Some places will get warmer, a few will get colder. (Northern Europe is in particular danger if the Gulf Stream gets messed up.) Point out that there is more _energy_ in the system which makes extreme things more common. That includes blizzards and such. ---
**Author:** ![Icerigger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/icerigger/32/432_2.png) [@Icerigger](https://boards.straightdope.com/u/Icerigger)\ **Post date:** [September 15, 2009, 5:26pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/3 "2009-09-15T17:26:32Z")
There was an article in my paper last week about two German ships sailing from Europe to Korea via the fabled Canadian North West Passage. This was thought to be forever impossible for merchant shipping unless it was an ice breaker or nuclear submarine. ---
**Author:** ![Spiff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spiff/32/9852_2.png) [@Spiff](https://boards.straightdope.com/u/Spiff)\ **Post date:** [September 15, 2009, 5:36pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/4 "2009-09-15T17:36:42Z")
I just sneer and remark that they need to learn the difference between weather and climate, and suggest they look in a dictionary. Dismissive, I know, but one cannot waste too much time on people who don’t want to learn. ---
**Author:** ![emarkp](https://avatars.discourse-cdn.com/v4/letter/e/3be4f8/32.png) [@emarkp](https://boards.straightdope.com/u/emarkp)\ **Post date:** [September 15, 2009, 6:09pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/5 "2009-09-15T18:09:30Z")
Icerigger, that’s annual weather, not climate. There is evidence both for and against GW (I currently feel the weight of evidence is against GW). But there are a few basic things to understand: The most significant greenhouse gasses are: water vapor, methane, carbon dioxide. All those gasses absorb and scatter infrared light. Thus, they act as a “blanket.” Infrared is the primary way that heat energy escapes earth, and slowing the escape means that there will be a tendency for heat to build up. As water vapor in the atmosphere increases, cloud cover increases, which reduces the amount of heat coming into the Earth (the so-called “thermostat effect”). It’s not entirely clear which effect dominates, but IMO GW is just not supported by the evidence. ---
**Author:** ![emarkp](https://avatars.discourse-cdn.com/v4/letter/e/3be4f8/32.png) [@emarkp](https://boards.straightdope.com/u/emarkp)\ **Post date:** [September 15, 2009, 8:09pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/6 "2009-09-15T20:09:30Z")
> [@Icerigger](#): > > There was an article in my paper last week about two German ships sailing from Europe to Korea via the fabled Canadian North West Passage. This was thought to be forever impossible for merchant shipping unless it was an ice breaker or nuclear submarine. And of course, [the entire story is error-riddled and false](http://eureferendum.blogspot.com/2009/09/turd-eaters.html). ---
**Author:** ![Least\_Original\_User\_Name\_Ever](https://avatars.discourse-cdn.com/v4/letter/l/e480ec/32.png) [@Least\_Original\_User\_Name\_Ever](https://boards.straightdope.com/u/Least_Original_User_Name_Ever)\ **Post date:** [September 15, 2009, 8:59pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/7 "2009-09-15T20:59:39Z")
> [@Johnny\_L.A](#): > > How does one explain global warming to people whose understanding of meteorology is limited to technology no greater than a [weather rock](http://en.wikipedia.org/wiki/Weather_Rock)? > > I have not debated global warming (natural or anthropogenic) with people like this, but their argument against global warming generally runs like this: ‘This is the worst Winter we’ve had since I can remember! So much for “global warming”!’ And they mean it. > > Is there a way, preferably using single syllables, to explain the interaction of (what appear to be to some people) small rises in the average global temperature, general meteorology, and other factors that result in specific weather in a region? That is, how does one explain that warmer weather in one part of the world will result in colder-than-normal temperatures where they are? Climate doesn’t equal weather. “Climate” is global, “weather” is local. I’m not talking about “weather change”, I’m talking about “climate change”. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 16, 2009, 6:44am UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/8 "2009-09-16T06:44:17Z")
> [@Johnny\_L.A](#): > > How does one explain global warming to people whose understanding of meteorology is limited to technology no greater than a [weather rock](http://en.wikipedia.org/wiki/Weather_Rock)? > > I have not debated global warming (natural or anthropogenic) with people like this, but their argument against global warming generally runs like this: ‘This is the worst Winter we’ve had since I can remember! So much for “global warming”!’ And they mean it. > > Is there a way, preferably using single syllables, to explain the interaction of (what appear to be to some people) small rises in the average global temperature, general meteorology, and other factors that result in specific weather in a region? That is, how does one explain that warmer weather in one part of the world will result in colder-than-normal temperatures where they are? [http://global-warming.accuweather.com/2009/08/second\_warmest\_july\_on\_record.html](http://global-warming.accuweather.com/2009/08/second_warmest_july_on_record.html) > [@](#): > > Second Warmest July on Record Globally, according to NASA > > NASA’s Goddard Institute of Space Studies (GISS) has determined that July of 2009 was the second warmest July globally, since records were kept going back well over a hundred years. > > The global land-ocean temperature anomaly for July 2009 was +.60 Celsius or +1.08 F. Only July of 1998 (a strong el nino year) was warmer. > > The image below shows the July 2009 anomalies across the globe (warm is red, cool is blue). Clearly the reds and oranges far outweigh the blues on this map. I mention that map because recently Drudge and other sources of denial have used the record low temperatures in July for Chicago and the North East in the USA to say that Global Warming was false, and Drudge and others **pointed to a blog from the same weather site**. (The owner of the blog had to add a note) [http://www.accuweather.com/mt-news-blogs.asp?blog=weathermatrix&pgurl=/mtweb/content/weathermatrix/archives/2009/07/1000\_low\_temp\_records\_set\_this\_july.asp](http://www.accuweather.com/mt-news-blogs.asp?blog=weathermatrix&pgurl=/mtweb/content/weathermatrix/archives/2009/07/1000_low_temp_records_set_this_july.asp) > [@](#): > > 1. The article was not meant to be a commentary on Climate Change or Global Warming (which is why I uttered neither phrase), though I understand why some thought that it was, given the link source 🙂 Cold OR warm outbreaks, by themselves, are not signs of Climate Change. I don’t have a strong opinion on the topic myself, though I feel that we don’t have enough data to make a decision. That said, if you’re into that sort of thing, please read our Global Warming Blog which attempts to present opinions from both sides. > > That said, here are some possibilities regarding Global Warming and this cool outbreak: > > - Maybe it would have been worse (6,000? 10,000? Truly a year without a Summer?) without Global Warming? > - Maybe it is a symptom of Climate Change (temperatures bend to extremes instead of staying near the average)? > - Maybe it is a sign that Global Warming is not as bad as we thought? > > 1. My blog entry was not meant to cover all the weather on the Globe in July, it was meant to cover the unusually cool weather that most of the U.S. has experienced this month. I even went out of my way to mention the Southwest Heat Wave, but clearly some readers were only skimming. 🙂 Now, when one looks at the early map, one can see how misleading colder-than-normal temperatures in a local area can be. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 16, 2009, 7:26am UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/9 "2009-09-16T07:26:15Z")
> [@emarkp](#): > > As water vapor in the atmosphere increases, cloud cover increases, which reduces the amount of heat coming into the Earth (the so-called “thermostat effect”). It’s not entirely clear which effect dominates, but IMO GW is just not supported by the evidence. Well, after checking many serious sources and reviews from academia, I would say that most scientists do think that there is plenty of support for AGW, and they did not reach that consensus quickly or by coincidence. Now, do we need to do something about it? What will be the results of that warming? Those are questions that still need to be researched and investigated. Until we find evidence that the natural sequestration of CO2 \*\*will \*\*keep up in the future with a good chunk of our emissions \*, then the discussion IMHO should be to make modest efforts to limit emissions of CO2 and other GW gases, and to help the nations that could be affected the most to develop and be prepared when more serious changes come by the end of the century thanks to GW. - This missing sink, contrary to what some deniers have reported, was already taken into account in many of the projections and simulations, regardless of it being somewhere, the fact is that CO2 levels continue to rise. As one researcher reported in a science blog, (paraphrasing) once we figure out where and how the “missing” sinks work, then scientists can advise people if modest efforts are just what is needed, or if we should be draconian if we want to have hope to control the situation, or if we should just give up and just work on minimizing the predicted effects. ---
**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:** [September 16, 2009, 3:32pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/10 "2009-09-16T15:32:26Z")
> [@GIGObuster](#): > > Well, after checking many serious sources and reviews from academia, I would say that most scientists do think that there is plenty of support for AGW, and they did not reach that consensus quickly or by coincidence. I’d rather not get into the cause of global warming. I believe it’s anthropogenic, but it may be part of a natural cycle. Either way, it seems clear that the Earth is warming up. **GIGObuster** : I’ll have to check out your links later, as I’m at work. Thanks for posting them. ---
**Author:** ![KellyCriterion](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@KellyCriterion](https://boards.straightdope.com/u/KellyCriterion)\ **Post date:** [September 16, 2009, 4:42pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/11 "2009-09-16T16:42:21Z")
Here’s a reasonable [4-part series on climate change](http://www.youtube.com/view_play_list?p=A4F0994AFB057BB8) (40 min total). ---
**Author:** ![emarkp](https://avatars.discourse-cdn.com/v4/letter/e/3be4f8/32.png) [@emarkp](https://boards.straightdope.com/u/emarkp)\ **Post date:** [September 16, 2009, 6:41pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/12 "2009-09-16T18:41:37Z")
> [@Johnny\_L.A](#): > > I’d rather not get into the cause of global warming. I believe it’s anthropogenic, but it may be part of a natural cycle. Either way, it seems clear that the Earth is warming up. I used to believe that. Then the hockey stick turned out to be bogus, and now it’s clear that the [vast majority of surface temperature stations have a significant warming bias](http://politicsandrandomness.blogspot.com/2009/06/end-of-global-warming.html). On top of that, it seems that [the original source data for temperature over the last 100+ years _has been lost_](http://www.theregister.co.uk/2009/08/13/cru_missing/). ---
**Author:** ![Shot\_From\_Guns](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@Shot\_From\_Guns](https://boards.straightdope.com/u/Shot_From_Guns)\ **Post date:** [September 16, 2009, 9:11pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/13 "2009-09-16T21:11:22Z")
1.) We can and have proven that CO[sub]2[/sub] causes a greenhouse effect. 2.) We know that interactions that cause one effect in controlled circumstances can cause a completely different effect in a complex system. For example, the condition known as [lupus anticoagulant](http://en.wikipedia.org/wiki/Lupus_anticoagulant) is called such because it acts as an anticoagulant _in vitro_, but \*in vivo \*(i.e., in an actual living human person), it acts in the complete opposite way: as a coagulant. (Fun side note: it’s not actually lupus, either.) 3.) Human beings have been dumping a shit-ton of CO[sub]2[/sub] (and other stuff) into the air since industrialization, and the climate is changing. It’s reasonable to assume that the two things are connected and not just correlated. Just because every square inch of the globe isn’t reacting the same way, or the way that might be predicted by small-scale experiments that can’t hope to remotely approach the level of complexity of our actual climate, doesn’t mean we aren’t changing things. ---
**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:** [September 16, 2009, 9:33pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/14 "2009-09-16T21:33:38Z")
Whether or not global warming is anthropogenic is irrelevant to the OP. The OP should point out that you have to look at it over the long term. And by that I mean in multiple decades and centuries. Only a few hundred years ago, we had the end of the Little Ice Age, when temperatures were much colder than they are now. And a few hundred years before that we had the end of the Medieval Warm Period. The OP should also point out that one cold snap does not mean much by itself, nor does one mild winter - nor one severe winter - but a succession of such over decades is significant. ---
**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:** [September 16, 2009, 9:36pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/15 "2009-09-16T21:36:08Z")
> [@Shot\_From\_Guns](#): > > 3.) Human beings have been dumping a shit-ton of CO[sub]2[/sub] (and other stuff) into the air since industrialization, and the climate is changing. It’s reasonable to assume that the two things are connected Actually, no it isn’t a reasonable assumption. It’s reasonable to **suspect** a link, but to assume a link is most certainly not reasonable and contrary to science. ---
**Author:** ![emarkp](https://avatars.discourse-cdn.com/v4/letter/e/3be4f8/32.png) [@emarkp](https://boards.straightdope.com/u/emarkp)\ **Post date:** [September 16, 2009, 10:36pm UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/16 "2009-09-16T22:36:48Z")
You nail it on the head, Quartz. When I first saw the surface level of evidence, my eyebrows went up. But the more I investigate the data, the more I conclude that the evidence favors that the Earth simply isn’t warming. This is similar (but opposite) to my experience with looking into Evolution for instance. I grew up with many people of the young-Earth creationism bent. The more I looked into Evolution, the more evidence I found in favor of it (and that continues to grow with DNA, molecular evidence, more transitional forms, etc.). In the case of warming, we have data that is suspect (surface stations as I mentioned) a model that isn’t confirmed IMO (the atmospheric profile of heat doesn’t match what is predicted by a warming blanket), and the computer models I’ve seen can’t predict the current climate based on historical methods (and don’t take cooling models into account). The failure of the hypothesis to make predictions that have been confirmed is why I reject the hypothesis, and the cagey nature of those who hold the data (refusing it to release it, hiding it once it’s found, etc.) means I don’t trust them, and when I look at the data I _can_ find doesn’t support the conclusion. IMO. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 17, 2009, 12:34am UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/17 "2009-09-17T00:34:41Z")
> [@emarkp](#): > > You nail it on the head, Quartz. When I first saw the surface level of evidence, my eyebrows went up. But the more I investigate the data, the more I conclude that the evidence favors that the Earth simply isn’t warming. > **[What has global warming done since 1998?](https://skepticalscience.com/global-warming-stopped-in-1998.htm)** > > \The planet has continued to accumulate heat since 1998 - global warming is still happening. Nevertheless, surface temperatures show much internal variability due to heat exchange between the ocean and atmosphere. 1998 was an unusually hot year due... > [@](#): > > What the science says… > > While 1998 was an unusually hot year due to El Nino, the long term trend since 1998 is still that of warming. > [@emarkp](#): > > This is similar (but opposite) to my experience with looking into Evolution for instance. I grew up with many people of the young-Earth creationism bent. The more I looked into Evolution, the more evidence I found in favor of it (and that continues to grow with DNA, molecular evidence, more transitional forms, etc.). History shows that it took a long time for many scientists to find out that indeed CO2 and other greenhouse gases were an issue. In the 40’s guys like Callendar proposed that there was evidence that GW was going to be a problem, but most scientists found Callendar’s calculations to be flawed, after they finished with him there was nothing left but the feathers. However, thanks to the cold war in the 50’s, we got evidence that showed that Callendar was onto something. [http://www.aip.org/history/climate/co2.htm](http://www.aip.org/history/climate/co2.htm) > [@](#): > > The scientists who brushed aside Callendar’s claims were reasoning well enough. (Subsequent work has shown that the temperature rise up to 1940 was, as his critics thought, mainly caused by some kind of natural cyclical effect, not by the still relatively low CO2 emissions. And the physics of radiation and climate was indeed too poorly known at that time to show whether adding more gas could make much difference.) Yet if Callendar was mistaken when he insisted he could prove global warming had arrived, it was a fortunate mistake. > Research by definition is done at the frontier of ignorance. Like nearly everyone described in these essays, Callendar had to use intuition as well as logic to draw any conclusions at all from the murky data and theories at his disposal. Like nearly everyone, he argued for conclusions that mingled the true with the false, leaving it to later workers to peel away the bad parts. While he could not prove that global warming was underway, he had given reasons to reconsider the question. We owe much to Callendar’s courage. His claims rescued the idea of global warming from obscurity and thrust it into the marketplace of scientific ideas. Not everyone dismissed his claims. Their very uncertainty attracted scientific curiosity. > > The Speculations Vindicated (1950-1960) TOP OF PAGE > The complacent view that CO2 from human activity could never become a problem was overturned during the 1950s by a series of costly observations. This was a consequence of the Second World War and the Cold War, which brought a new urgency to many fields of research. American scientists enjoyed massively increased government funding, notably from military agencies. The officials were not aiming to answer academic questions about future climates, but to provide for pressing military needs. Almost anything that happened in the atmosphere and oceans could be important for national security. Among the first products were new data for the absorption of infrared radiation, a topic of more interest to weapons engineers than meteorologists.(23) > > The early experiments that sent radiation through gases in a tube, measuring bands of the spectrum at sea-level pressure and temperature, had been misleading. The bands seen at sea level were actually made up of overlapping spectral lines, which in the primitive early instruments had been smeared out into broad bands. Improved physics theory and precise laboratory measurements in the 1940s and after encouraged a new way of looking at the absorption. Scientists were especially struck to find that at low pressure and temperature, each band resolved into a cluster of sharply defined lines, like a picket fence, with gaps between the lines where radiation would get through.(24) The most important CO2 absorption lines did not lie exactly on top of water vapor lines. Instead of two overlapping bands, there were two sets of narrow lines with spaces for radiation to slip through. So even if water vapor in the lower layers of the atmosphere did entirely block any radiation that could have been absorbed by CO2, that would not keep the gas from making a difference in the rarified and frigid upper layers. Those layers held very little water vapor anyway. And scientists were coming to see that you couldn’t just calculate absorption for radiation passing through the atmosphere as a whole, you had to understand what happened in each layer — which was far harder to calculate. > > Digital computers were now at hand for such calculations. The theoretical physicist Lewis D. Kaplan decided it was worth taking some time away from what seemed like more important matters to grind through extensive numerical computations. In 1952, he showed that in the upper atmosphere, adding more CO2 must change the balance of radiation significantly.(25) > [@emarkp](#): > > In the case of warming, we have data that is suspect (surface stations as I mentioned) a model that isn’t confirmed IMO (the atmospheric profile of heat doesn’t match what is predicted by a warming blanket), and the computer models I’ve seen can’t predict the current climate based on historical methods (and don’t take cooling models into account). > **[Does Urban Heat Island effect exaggerate global warming trends?](https://skepticalscience.com/urban-heat-island-effect.htm)** > > While urban areas are undoubtedly warmer than surrounding rural areas, this has had little to no impact on warming trends. > [@](#): > > What the science says… > > While urban areas are undoubtedly warmer than surrounding rural areas, this has had little to no impact on warming trends. > **[How reliable are climate models?](https://skepticalscience.com/climate-models.htm)** > > \While there are uncertainties with climate models, they successfully reproduce the past and have made predictions that have been subsequently confirmed by observations.\ > [@](#): > > What the science says… > > While there are uncertainties with climate models, they successfully reproduce the past and have successfully predicted future climate change. > [@emarkp](#): > > IMO. Well, you are indeed entitled to your opinions but not the facts. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 17, 2009, 12:40am UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/18 "2009-09-17T00:40:50Z")
> [@Quartz](#): > > Whether or not global warming is anthropogenic is irrelevant to the OP. The OP should point out that you have to look at it over the long term. And by that I mean in multiple decades and centuries. Only a few hundred years ago, we had the end of the Little Ice Age, when temperatures were much colder than they are now. And a few hundred years before that we had the end of the Medieval Warm Period. The OP should also point out that one cold snap does not mean much by itself, nor does one mild winter - nor one severe winter - but a succession of such over decades is significant. Well, IMO you are confusing very localized events with global ones, just like in the example of the cool temperatures during July in the north east of the USA. > **[RealClimate: Weren’t temperatures warmer than today during the “Medieval Warm...](https://www.realclimate.org/index.php/archives/2004/12/werent-temperatures-warmer-during-the-medieval-warm-period-than-they-are-today/)** > > RealClimate: This is one of a number of popular myths regarding temperature variations in past centuries. At hemispheric or global scales, surface temperatures are believed to have followed the "Hockey Stick" pattern, characterized by a long-term... > [@](#): > > Weren’t temperatures warmer than today during the “Medieval Warm Period”? > > This is one of a number of popular myths regarding temperature variations in past centuries. At hemispheric or global scales, surface temperatures are believed to have followed the “Hockey Stick” pattern, characterized by a long-term cooling trend from the so-called “Medieval Warm Period” (broadly speaking, the 10th-mid 14th centuries) through the “Little Ice Age” (broadly speaking, the mid 15th-19th centuries), followed by a rapid warming during the 20th century that culminates in anomalous late 20th century warmth. The late 20th century warmth, at hemispheric or global scales, appears, from a number of recent peer-reviewed studies, to exceed the peak warmth of the “Medieval Warm Period”. Claims that global average temperatures during Medieval times were warmer than present-day are based on a number of false premises that a) confuse past evidence of drought/precipitation with temperature evidence, b) fail to disinguish regional from global-scale temperature variations, and c) use the entire “20th century” to describe “modern” conditions , fail to differentiate between relatively cool early 20th century conditions and the anomalously warm late 20th century conditions. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [September 17, 2009, 12:53am UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/19 "2009-09-17T00:53:58Z")
IMHO Humanity, the fetal child in the womb of mother earth thinks, in all our ‘wisdom’, that we can actually do better trying to figure our things on our own then depend on our mother earth and our Heavenly Father who created everything in absolute perfection. As such we have cut ourselves off from our mother, trying to recycle our own waste, and trying to reclaim our own respiration, something we were never designed to do, and something our mother is well equipped to deal with. As such we, the fetal child of mother earth, is running a fever. ---
**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:** [September 17, 2009, 6:00am UTC](https://boards.straightdope.com/t/explaining-global-warming/510176/20 "2009-09-17T06:00:25Z")
> [@RealClimate](#): > > Claims that global average temperatures during Medieval times were warmer than present-day But I’m not saying that, am I? I’m saying that the OP should point out that there was a warm period. > [@RealClimate](#): > > fail to differentiate between relatively cool early 20th century conditions and the anomalously warm late 20th century conditions. That’s a huge weasel: the early 20th century was warmer than the Little Ice Age. Anyway, global warming is not in doubt. I’ll reiterate to the OP that he needs to talk about the long term. [Next page](https://boards.straightdope.com/t/explaining-global-warming/510176.md?page=2)