# Humans "Impact" on Planet Earth **URL:** \ **Category:** Factual Questions\ **Created:** [February 24, 2009, 11:35am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184 "2009-02-24T11:35:21Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [February 25, 2009, 12:27am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/21 "2009-02-25T00:27:43Z")
[QUOTE=Sailboat] The area of sea floor that’s dredged each year – killing millions of animals, with unknown impact – is larger than the continental United States. [/QUOTE] > [@Moonshiner](#): > > Cite, please. You mean, cite beacuse you’re wowed by the figure? Cite because you’re interested in conservation? Or is this one of those adversarial “Cite, please” requests done only to harass someone and impugn the point being made? Please expand on your request. While you’re doing that, here’s your cite: [ > [@](#): > > “Bottom trawling is the most destructive of any actions that humans conduct in the ocean,” said Dr. Watling. “Ten years ago, Elliott Norse and I calculated that, each year, worldwide, bottom trawlers drag an area equivalent to twice the lower 48 states.” ]([http://www.ens-newswire.com/ens/feb2008/2008-02-15-096.asp](http://www.ens-newswire.com/ens/feb2008/2008-02-15-096.asp)) Oops, looks like I owe you an apology – I understated it. It’s an area TWICE the continental United States. Annually. This was big news when it was first discussed, ten years ago. How big? Well, the oceans are the foundation of life on earth, and twice the area of the contiental US being raked over and largely destroyed annually makes this one of the most important news stories, well, imaginable, doesn’t it? I mean this is a real-life doomsday plot like something a Bond villain would attempt. Clearly it’s orders of magnitude more important than, say, 9-11, for God’s sake, and a greater threat to the United States. You’ve heard of 9-11, have you? But you needed a cite for this? Wonder why you don’t already know it? Because people (in general, news services included) don’t know how to deal with this kind of news. Everyone takes a “see no evil, hear no evil, speak no evil” attitude, and goes back to Googling Lindsay Lohan. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [February 25, 2009, 12:39am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/22 "2009-02-25T00:39:24Z")
> [@Sailboat](#): > > Oops, looks like I owe you an apology – I understated it. It’s an area TWICE the continental United States. Annually. I don’t have any axe to grind in this area of the discussion, but that sounds like suspicious math to me. I’d be willing to bet that this total area is arrived at by claiming that, say, one square mile that gets dragged 6 times a year counts as six square miles. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [February 25, 2009, 1:13am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/23 "2009-02-25T01:13:49Z")
> [@Sailboat](#): > > You mean, cite beacuse you’re wowed by the figure? Cite because you’re interested in conservation? Or is this one of those adversarial “Cite, please” requests done only to harass someone and impugn the point being made? Please expand on your request. > > While you’re doing that, here’s your cite: > > Oops, looks like I owe you an apology – I understated it. It’s an area TWICE the continental United States. Annually. > > This was big news when it was first discussed, ten years ago. How big? Well, the oceans are the foundation of life on earth, and twice the area of the contiental US being raked over and largely destroyed annually makes this one of the most important news stories, well, imaginable, doesn’t it? I mean this is a real-life doomsday plot like something a Bond villain would attempt. Clearly it’s orders of magnitude more important than, say, 9-11, for God’s sake, and a greater threat to the United States. You’ve heard of 9-11, have you? But you needed a cite for this? Wonder why you don’t already know it? Touchy, much? It was an entirely legitimate request for justification for an unsubstantiated claim. Also, I wouldn’t cite “The Environmental News Service” as an objective or technical authority on the topic as they obviously have an axe to grind. (One doubts that they’d publish a headline like “Earth Just Fine! Everything In Balance!” even if it were true.) I’d tend toward at least something like the [United Nations Environmental Programme](http://earthwatch.unep.net/oceans/oceanfisheries.php) which cites some authoritative published sources. Stranger ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [February 25, 2009, 3:49am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/24 "2009-02-25T03:49:55Z")
> [@Stranger\_On\_A\_Train](#): > > Touchy, much? It was an entirely legitimate request for justification for an unsubstantiated claim. And that’s all he contributed to the thread, not even any indication of his thoughts. just a challenge. I asked for explication. > [@Stranger\_On\_A\_Train](#): > > Also, I wouldn’t cite “The Environmental News Service” as an objective or technical authority on the topic as they obviously have an axe to grind. (One doubts that they’d publish a headline like “Earth Just Fine! Everything In Balance!” even if it were true.) I’d tend toward at least something like the [United Nations Environmental Programme](http://earthwatch.unep.net/oceans/oceanfisheries.php) which cites some authoritative published sources. > > Stranger From YOUR cite: > [@](#): > > The area trawled each year is about equivalent to 150 times the total forest area clear-cut yearly and corresponds to about an area twice the size of the contiguous United States (Norse, 1998). From mine: > [@](#): > > Speakers at the session included Dr. Elliott Norse, > > \ > > “Bottom trawling is the most destructive of any actions that humans conduct in the ocean,” said Dr. Watling. “Ten years ago, Elliott Norse and I calculated…” So my cite quotes one of Dr. Norse’s coauthors speaking in Dr. Norse’s presence and describing their results. Yours paraphrases Dr. Norse’s study. My citation is factually correct and mildly more interesting. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [February 25, 2009, 5:52am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/25 "2009-02-25T05:52:39Z")
> [@Sailboat](#): > > And that’s all he contributed to the thread, not even any indication of his thoughts. just a challenge. I asked for explication. No, you took an accusatory, passive-aggressive, hyperbolic stance. > [@Sailboat](#): > > My citation is factually correct and mildly more interesting. Your citation, such as it is, lacks any substantiation, quantified data, or source bibliography; in other words, it provided nothing that could be debated or contended, just (at best) journalistic advocacy and apparently specious factoids. The citation I provided gave firm numbers to debate and at least four bibliographic references from widely respected peer-reviewed journals as well as several published surveys and reports which have been by scrutinized by subject matter experts. If you sincerely believed that the request for a cite was “done only to harass someone and impugn the point being made,” responding with an authoritative and well-supported citation (which took me all of 45 seconds to find with a simple Internet search with a widely used search engine) is a far more effective and civil position than snarky bombast and feigned offense, not only to the inquisitor (who may or may not have a genuine interest in the answer) but to other readers who are sincerely interested in supporting evidence for the claim. Stranger ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [February 25, 2009, 6:49am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/26 "2009-02-25T06:49:33Z")
I don’t think showing how much space human beings physically occupy really says anything about the human impact on the Earth. I’d say a better factor would be what percentage of the Earth’s surface shows evidence of human impact. My guess is that it’s over fifty percent by even a pretty narrow definition. > [@](#): > > Yet to our perspective, the oceans are deep, vast and full of more resources than we could use in a millennium. I found this one ironic. The obvious rebuttal is that human beings have already been taking resources out of the ocean for a lot longer than a millennium. It’s like saying “I don’t have to make financial plans. I’m so rich I would take me a decade to spend all my money.” ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [February 25, 2009, 7:27am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/27 "2009-02-25T07:27:39Z")
> [@Quartz](#): > > Cites, please? I thought the current theory was that the Sahara is a desert due to gradual desertification following the end of the last ice age. If a place doesn’t receive much rain, it cannot help but be a desert, can it? I’m not saying that humans haven’t aggravated the expansion, but to lay the blame entirely at the feet of humanity seems wrong. I can’t find a cite, but the theory I’ve heard is that goat herding was at least a major factor if not the sole cause. ---
**Author:** ![Simple\_Mind](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Simple\_Mind](https://boards.straightdope.com/u/Simple_Mind)\ **Post date:** [February 25, 2009, 1:36pm UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/28 "2009-02-25T13:36:35Z")
> [@Little\_Nemo](#): > > \*\*I don’t think showing how much space human beings physically occupy really says anything about the human impact on the Earth. I’d say a better factor would be what percentage of the Earth’s surface shows evidence of human impact. My guess is that it’s over fifty percent by even a pretty narrow definition.\*\*I found this one ironic. The obvious rebuttal is that human beings have already been taking resources out of the ocean for a lot longer than a millennium. It’s like saying “I don’t have to make financial plans. I’m so rich I would take me a decade to spend all my money.” I stated in my post that I “overheard” this statements, I did not say that I found them correct or that I agree with them, what I was asking is how much area our "Activities"would cover on the 8’Foot Globe, “Little Nemos” reply was the only one that attempted to answer that question! I know very well myself that the whole argument can not be discussed so simply but I was expecting a bit more imagination and not so much “infighting” ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [February 25, 2009, 2:16pm UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/29 "2009-02-25T14:16:11Z")
> [@Der\_Trihs](#): > > I can’t find a cite, but the theory I’ve heard is that goat herding was at least a major factor if not the sole cause. I’ve heard and seen the same story but I have never seen a factual study/article on it. If said exists, I would love to see it. This is not worth anything as a [cite but here is an example of the theory](http://boards.history.com/topic/Africa/Did-The-Romans/1481)in post #3. Wiki does not support this theory and as I said, I have never seen it in a reliable source. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [February 25, 2009, 2:39pm UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/30 "2009-02-25T14:39:54Z")
> [@Stranger\_On\_A\_Train](#): > > No, you took an accusatory, passive-aggressive, hyperbolic stance. Okay, I came on a little strong. My views may be colored by my frustration at the “head in the sand” approach people take to environmental issues. I’ve been particularly cranky about the urgency people seem to feel to stop Somalian pirates while ignoring the deep-sea bottom trawlers, which seem to be doing orders of magnitude more damage. Please consider my attitude adjusted. ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [February 26, 2009, 6:30am UTC](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184/31 "2009-02-26T06:30:24Z")
> [@KneadToKnow](#): > > I don’t have any axe to grind in this area of the discussion, but that sounds like suspicious math to me. I’d be willing to bet that this total area is arrived at by claiming that, say, one square mile that gets dragged 6 times a year counts as six square miles. 1. Even if you count just the different areas trawling affects it’s a vast area: > [@Kaiser et al. 2002](#): > > The ubiquity of trawling is revealed by a recent analy- > sis where catches were mapped to country continen- > tal shelves (refer to the effort data that Ian did for the > Montpellier conference); trawling and dredging > activity was reported from 19 984 200 km2 of coun- > try continental shelves, which represents about 75% > of the global continental shelf. Although there is sig- > nificant variation in catch density (catch by a coun- > try divided by the area of continental shelf), it is > clear that demersal trawling and dredging is an ubi- > quitous global activity on continental shelves. Citation: Kaiser et al. 2002. Modification of marine habitats by trawling activities: prognosis and solutions. _Fish and Fisheries_ **3** , 1-24. [Link](http://web.ebscohost.com/ehost/pdf?vid=2&hid=120&sid=12d1745e-2a6a-4195-b5ad-a1f6547d9136%40sessionmgr107) 20 million square km - by comparison, the area of the US is [9.8 million square km](http://en.wikipedia.org/wiki/United_States). 2. More importantly, it makes it worse that the same areas are frequently trawled. Trawling is dragging large fishing gear across the bottom to catch benthic or demersal organisms, and dragging huge nets across habitat does lots of damage to that habitat (with the exception of some resilient shallow sandy bottoms,) sufficient to damage areas for months to years. Fishermen/women don’t want to trawl there again immediately since the catch will be reduced, but they do want to come back in a matter of months (or years, depending on the target species) when the habitat has had some time to recover (although they have _no_ incentive to allow the habitat to fully recover.) Then the habitat gets damaged over and over again to the point where it doesn’t ever get a chance to completely recover. [Previous page](https://boards.straightdope.com/t/humans-impact-on-planet-earth/487184.md?page=1)