# Why is Mars undergoing global warming? **URL:** \ **Category:** Great Debates\ **Created:** [March 31, 2006, 11:35pm UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778 "2006-03-31T23:35:43Z")\ **Posts on this page:** 9\ **Page:** 8
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [April 3, 2006, 1:56pm UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/141 "2006-04-03T13:56:45Z")
> [@jshore](#): > > **Sam** , it has not been discredited. There is still plenty of legitimate debate in the field of these temperature reconstructions over the last couple of millenia using climate proxies and some reconstructions do show more variations over the last 1000 years than Mann et al. show. However, these different studies all tend to agree that the warming of the late 20th century is unprecedented (at least in the Northern Hemisphere where the data is better) over the last 1000 years. And, most of the criticisms of M&M have been shown to be specious. See [here](http://www.realclimate.org/index.php/archives/2006/02/a-new-take-on-an-old-millennium/). Of course, this is written Michael Mann, one of the authors of the original hockey stick, but it provides references to recent peer-reviewed work on the subject. I didn’t mean to say that the notion of man-caused warming itself has been disproved - at this point, I think there should be widespread agreement that this is in fact happening. I was speaking of one particular graph which seems kind of… extreme. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [April 3, 2006, 2:07pm UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/142 "2006-04-03T14:07:48Z")
> [@Sam Stone](#): > > I didn’t mean to say that the notion of man-caused warming itself has been disproved - at this point, I think there should be widespread agreement that this is in fact happening. I was speaking of one particular graph which seems kind of… extreme. A global average increase of over 1[sup]o[/sup]C in mere decades _is_ extreme, wouldn’t you agree? ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [April 3, 2006, 3:28pm UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/143 "2006-04-03T15:28:16Z")
Two scientists were wrong in the seventies. Ergo, they must all be wrong now. Is that the argument here? ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [April 3, 2006, 3:44pm UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/144 "2006-04-03T15:44:45Z")
> [@Sam Stone](#): > > I didn’t mean to say that the notion of man-caused warming itself has been disproved - at this point, I think there should be widespread agreement that this is in fact happening. I was speaking of one particular graph which seems kind of… extreme. Right, but my point is that most of the claims made by the two Canadians (M&M) in regards to problems with that one particular graph have been shown to be incorrect. And, while it is true that some other research has suggested that the “handle” of the hockey stick may not be as flat as Mann et al. found, this is by no means settled one way or the other. And, even if (for example) the wavier reconstruction found by Moberg et al. is correct, it is still in line with the statement that the IPCC drew from the Mann et al. work that the late 20th century warmth across the Northern Hemisphere is likely larger than anything seen in the last millenium…although admittedly the visual picture presented by the Mann et al. graph, relative to the wavier Moberg graph, makes the 20th century warming seem more dramatically anomalous. But, you do touch on another point worth emphasizing which is that, indeed, this is just one particular graph touching on one particular piece of evidence related to anthropogenic global warming…and, in fact, the most circumstantial piece of evidence. There is indeed a lot of other independent evidence to suggest that most of the current (latter half of the 20th century and into this new century) warming is anthropogenic and cannot be explained by natural causes. ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [April 3, 2006, 4:33pm UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/145 "2006-04-03T16:33:46Z")
[http://thinkprogress.org/2006/04/03/willful-deception/](http://thinkprogress.org/2006/04/03/willful-deception/) ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [April 3, 2006, 4:44pm UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/146 "2006-04-03T16:44:39Z")
> [@Flash Dancer](#): > > Numerous peer reviewed publications and presentations over the past few years ~ probability / statistics I don’t get it - you’ve published peer reviewed papers on probability and statistics, you have a hypothesis that global warming is statistically insignificant, and yet you’re unwilling to post your calculations and instead ask other posters to: > [@Flash Dancer](#): > > Let’s try to prove that the recent global warming trend is significant based on accepted statistical / probability theory. I provided extensive yty temperature data from which the variance can be ascertained (and btw, which is essentially independent of its accuracy ) … waiting for some one here to give me the sigma … You seem to be perfectly capable of performing these calculations yourself. Why don’t you perform the calculations, and if you are willing to share them, post the work and we can discuss it and the relevance of the assumptions required to make those calculations. If you are unwilling to share them because you want to publish them, submit it to a journal for peer review. If you are unwilling to share them period, keep them to yourself and don’t take part in the scientific process. I don’t get the part about asking others to do what you seem to be perfectly capable of doing yourself. 😕 ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [April 9, 2006, 7:52am UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/147 "2006-04-09T07:52:14Z")
> [@SentientMeat](#): > > Both Earth and Mars have gone through cycles of heating and cooling in their history, with solar cycles palying a large part. So, Mars and _Earth before around 1980_ can be explained “naturally”. > > However, those explanations break down after around 1980 in the case of Earth. Look at [these graphs](http://www.ipcc.ch/present/graphics/2001syr/large/02.01.jpg). You’ll note that before around 1960, none of these greenhouse gases were _too_ far off the historical equilibrium concentration (eg. 280 parts per million for CO2). However, after that date you’ll note the concentrations begin to rocket, and their increase is still exponential today. This is why attempts to explain current warming trends _naturally_ fail for post-1980 data, while Anthropogenic Climate Change (ACC) models are largely accurate. > > There are almost no ACC-deniers in professional or academic climatology any more. Slight correction, the CO2 levels are _ **not** _ increasing exponentially … Take a look at the Mauna Loa numbers, the increase has been no more than linear since about 1975. Which of course makes me wonder about the reliability of your other info … w. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [April 9, 2006, 11:23am UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/148 "2006-04-09T11:23:26Z")
> [@intention](#): > > Slight correction, the CO2 levels are _ **not** _ increasing exponentially … Take a look at the Mauna Loa numbers, the increase has been no more than linear since about 1975. > > Which of course makes me wonder about the reliability of your other info … Apologies, you’re quite right - I was using the word as a figure of speech rather than strictly mathematically. The ppm increase is not doubling every year, of course. But I’d disagree about it being “no more than” linear: 2005 saw the [biggest ever increase](http://www.bbc.co.uk/worldservice/learningenglish/newsenglish/witn/2006/03/060315_co2.shtml). ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [April 12, 2006, 5:58am UTC](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778/149 "2006-04-12T05:58:16Z")
SentientMeat, thanks, you are right about 2005. The rate of emission of CO2 has been rising slowly since about 1975, when it leveled off from its post-war burst … [Previous page](https://boards.straightdope.com/t/why-is-mars-undergoing-global-warming/350778.md?page=7)