<p>You've correctly identified a number of individual mechanisms which form "vicious circles". They're more formally known as "positive feedbacks". As you've noted, loss of albedo (reflectivity) from melted ice is one. Some of the others you've listed are a bit more complex - e.g. trees will regrow, algae in oceans are quite effective at removing CO2, etc.</p>

<p>One of the big concerns that people have is that if some of the larger positive feedback mechanisms get going - e.g. the melting of frozen methane on the seafloor - then it will impossible for anything that mankind does to stop it, and even if we completely stop emitting greenhouse gases we'll get pushed to a much warmer climate.</p>

<p>There are also negative feedback mechanisms. For example, a warmer atmosphere is likely to have more clouds, which will reflect more sunlight. But the warmer atmosphere can also hold more water vapour, which itself is a greenhouse gas, which is a positive feedback. </p>

<p>One of the reasons that climate science is hard is that all of these positive and negative feedbacks interact, making the earth system a very complex one.</p>

CC BY-SA 4.0
2020-01-14T13:48:52.687Z
@ebv two of those are things I already mentioned....
Semidiurnal Simon
CC BY-SA 4.0
2020-01-14T16:04:24.480Z
@ebv fair enough! I'm not going to edit into here, because there's a good, and more comprehensive answer, already. But thanks :)
Semidiurnal Simon
CC BY-SA 4.0
2020-01-16T13:12:55.513Z
Climate science isn't hard! Don't be ridiculous. These complex mechanisms and cross-interacting factors? Nonsense. All you _really_ need is a little bar chart with some cherry-picked temperature data from the last hundred years or so, share it on Facebook, and presto! You're an expert. Duh.
Lightness Races in Orbit
CC BY-SA 4.0
2020-01-17T09:23:43.220Z
Ad melting of frozen methane - it's not that humans couldn't do anything to stop the planet from warming, it's just the point where reducing the carbon dioxide production isn't going to be enough (i.e. even if we cut all carbon dioxide emissions, the methane will produce as much or more as we used to). We can still do things like add particulates or sulphur dioxides to the atmosphere, produce radiators that reflect most light but have high emission in the right IR range etc. The difference is we're no longer in the "let's go back mode", but exploring new climate territory :)
Luaan
CC BY-SA 4.0
2020-01-14T10:45:25.277Z
2020-01-14T10:45:25.277Z
Semidiurnal Simon
<p>Climate Change definitely seem like a vicious cycle on a decadal scale. As other answers have pointed out there are numerous positive <a href="https://climate.nasa.gov/nasa_science/science/" rel="nofollow noreferrer">feedbacks</a> such as:</p>
<ol>
<li>Warmer atmosphere holding more water vapor (which is a GHG) leading to more clouds</li>
<li>Reduced snow cover reflecting less solar radiation (lower albedo)</li>
<li>Reduced snow and ice cover on land leading to faster release of previously &quot;locked up&quot; methane in permafrost</li>
<li>Warming increases decomposition of organic matter in general ( particularly worrying in previously waterlogged area e.g. peatland)</li>
</ol>
<p>However, this &quot;vicious cycle&quot; will likely decrease in strength over time, for reasons like blackbody radiation mentioned in the other answer. &quot;Potential&quot; full or partial reversal of the cycle, however, is dependant on biospheric feedbacks (blackbody radiation can only stabilize). Simply put, organisms collectively tend to stabilize environmental variables within certain ranges for homeostasis sake (humans are outliers, unfortunately), especially for bioresources like carbon dioxide and methane. I argue from an evolutionary standpoint, that <strong>most biospheric negative feedbacks</strong> (which is in essence ecological responses refined through eons of large-scale nutrient imbalance selection experiment) <strong>operate on a larger timescale than the aforementioned positive feedbacks</strong> because throughout Earth's history, it is unlikely that the Earth has experienced the current fast rate of warming that results in effective selection dynamics (you may argue we had seen that but massive and scarce pulse disaster is an example of ineffective selection that doesn't lead to meaningful adaptation and act more like lottery, whereas continuous and gradual impact is the best form of selection pressure). If there exists a biospheric &quot;negative feedback&quot; mechanism that leads to very fast cooling, in itself it would not be sustainable (just like fast warming) and would be weed out by evolution.</p>
<p>So enough of evolutionary theory, how does an ecological negative feedback work (approximately)?</p>
<p>Carbon dioxide fertilization and warming would favor and select the most efficient primary producers within the community repository (those who can use CO2 for growth and reproduction efficiently would be able to expand in numbers). Globally, in ocean, it would be r-strategists (phytoplanktons) that can grow and reproduce quickly whereas on land it would be trees that have conquered the limitation of height in primary production (I'm talking about in general what would be favored, there would be local variation no doubt). Also, note that two of the fastest flowing nutrient cycles i.e. C and N cycles are to some extent coupled and increased N deposition has indeed been shown to reinforce carbon sequestration (there is solid evidence of the increase in concentration of N compounds in the atmosphere which would deposit back to the environment when rained down.)</p>
<p>It should be noted that while the primary producers have some time to enjoy the &quot;feast&quot;, the increased input of organic matter (OM) in the ecosystems (from primary producers) in turns constitute another selection pressure to select the most efficient consumers and decomposers. The duo processes would get closer and closer to an equilibrium eventually, but it is not likely to be the same state we had seen in pre-industrial time.</p>
<p>So yes, in the &quot;short-term&quot; i.e. decades (which in itself is considered &quot;long&quot; relative to human lifespan), climate change does seem like a vicious cycle but on a longer-term it would likely find its &quot;peace&quot; through wax and wanes of biospheric responses.</p>

CC BY-SA 4.0
2020-01-18T20:09:35.593Z
2020-01-19T13:53:15.720Z
2020-06-18T08:25:19.090Z
y chung
<p>The wording of the question suggests that it is asking about what climate scientists refer to as a run-away feedback. There are, and always have been, positive feed-backs in the climate system, but these are balanced by the major stabilizing effect of emitted infra-red radiation: the simple fact that the Earth emits more heat to space when it is warmer, and this tends to counter-act and heating effect. </p>

<p>Hence, our climate behaves like a benign, self-stabilizing system, not one that spirals out of control as soon as it is perturbed. </p>

<p>For instance, a 1 degree Celcius warming will increase the amount of water vapor in the atmosphere by about 6-7% (because hotter air can carry more water -- see, for examnple, <a href="https://skepticalscience.com/print.php?r=44" rel="nofollow noreferrer">skeptical science</a>). Water vapor is a greenhouse gas, so this extra water vapor will create extra heating of around 2.2 W m-2 (<a href="https://phys.org/news/2014-03-effect-vapor-climate.html" rel="nofollow noreferrer">AGU Report</a>). At the same time, an extra degree of Celcius means that the Earth is radiating more heat to space. This can be estimated from the Stephan-Boltzman law (maths omitted) and it turns out that 1 degree Celcius of warming results in roughly an additional 6 W m-2 being emitted to space. The extra cooling effect (6 W m-2) is greater than the feedback effect  (2.2 W m-2) so the net effect is that when the Earth's climate is subjected to a temporary warming it will cool back to its equilibrium.</p>

<p><strong>The reason why we see exponential warming now is not because of a vicious feedback, it is because we are applying an exponentially increasing forcing.</strong> </p>

<p>However, there is no absolute physical law which says that the stabilizing effect of emitted infrared radiation always has to win over the feed-backs. There is a concern that rising temperatures might strengthen the feed-backs so much that they overwhelm the stabilizing effects, leading to an unstoppable run-away feedback which could well wipe out all mammals, us included. That would be vicious. It has to be said, of course, that there are no credible predictions of a run-away feedback anytime soon -- the debate there is whether our models would be able to spot one before it happened. </p>

CC BY-SA 4.0
2020-02-15T20:03:39.793Z
2020-02-15T20:03:39.793Z
M Juckes
<p>Yes, you are quite right, it does create a vicious circle, though not quite as vicious as some might think. As you suggest, there are natural forces which ameliorate the effects of this vicious circle.</p>

<p>Most of the woodland burned by these fires regenerates, though this takes a while. Where it doesn't regenerate, its place is usually taken by agriculture, which also consumes CO2, but less effectively than trees.</p>

<p>The de-icing of the NW and NE Passages will allow ships to take short cuts to their destinations and thus use less fuel, which lowers CO2 emissions.</p>

<p>The increased CO2 in the atmosphere will allow vegetation, both natural and agricultural, to grow more efficiently by perhaps a few percent. This applies not only in the rainforest, but in the oceans where the majority of photosynthesis takes place (in this context I include all photosynthetic marine organisms, not just vegetation as we normally think of it).</p>

<p>Just as there are more factors which create a vicious circle, so there are more ameliorating factors which lessen it, but not enough to prevent an increase in the vicious circle you speak of in your question.</p>

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2020-01-15T13:08:22.247Z
Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/103333/discussion-on-answer-by-michael-walsby-is-climate-change-a-vicious-circle), minus previously deleted comments. Note that the [Code of Conduct](https://stackoverflow.com/conduct) still applies in chat: keep it civil.
gerrit
CC BY-SA 4.0
2020-01-14T10:17:04.347Z
2020-01-14T10:17:04.347Z
Michael Walsby
<p>It isn't Co2 (sorry I know that's likely unpopular for most to hear), it's (primarily) the sun.</p>

<p>Real quick, rising Co2 doesn't cause wildfires, trees love Co2, visit a greenhouse. Wildfires are a result of (bleep holes) running around lighting fires. Look it up, nearly 200 people arrested so far in Australia for arson.</p>

<p>Ocean rise prediction data (focused on Co2) fails to account for increased plant intake due to plant growth explosion. Similarly, population reduction doesn't account for the 12 gallons of water that makes up an average male. Reduce population by 1 million average men, increase water levels by approx 12 million gallons.</p>

<p>The ice was always supposed to melt, it's a byproduct of a catastrophe.</p>

<p>However, the long answer to your point is technically "classified" by the U.S. military and a secret. It was part of my training in the USAF, couldn't do my job unless they told me. What's classified is less the information but more our comprehension of it. Foreign nations know of it, they just don't have the big picture. Once you know, Climate Change is literally a hoax as it's currently being peddled.</p>

<p>This is one entity that monitors the real source of our "Climate Change" <a href="https://www.swpc.noaa.gov/products/planetary-k-index" rel="nofollow noreferrer">NOAA</a></p>

<p>This site also has some good info; <a href="https://web.ua.es/docivis/magnet/earths_magnetic_field2.html" rel="nofollow noreferrer">Earth's Electromagnetic Field</a></p>

<p>My previous source was NORAD, I'm retired now, can't access it so, NOAA is the closest thing I've found publically available. We referred to it as "Geo-Planetary Index", it was/is monitored by the "minute" because it's that critical to success of the military's mission.</p>

<p>I don't know if politicians know the truth but some manufacturers clearly do. One example; <a href="https://en.wikipedia.org/wiki/ECC_memory" rel="nofollow noreferrer">ECC_memory</a></p>

<p>I'm not a fan of using Wiki however, the author of this excerpt from the above link knows what I know; "research has shown that the majority of one-off soft errors in DRAM chips occur as a result of background radiation, chiefly neutrons from cosmic ray secondaries, which may change the contents of one or more memory cells or interfere with the circuitry used to read or write to them.[3] Hence, the error rates increase rapidly with rising altitude; for example, compared to sea level, the rate of neutron flux is 3.5 times higher at 1.5 km and 300 times higher at 10–12 km (the cruising altitude of commercial airplanes).[4] As a result, systems operating at high altitudes require special provision for reliability."</p>

<p>If the public really wants to have an appreciable effect on the temperature, find a way to make the roadways, solar panels white/reflective. Plant more green things...</p>

<p>Edit/Update: Just keep this in mind, Co2 not being the cause isn't my "opinion". It doesn't matter if you have a PhD in "Climate Studies", it doesn't change reality.</p>

<p>More things to consider:</p>

<p>How many colliders are on the planet? (Hint: 40% are underground/classified i.e. don't exist, why?)
What alternative things are they used for beyond scientific study?
When do they fire them?
Where are they geo located, what's unique about their placement?
Why are they often fired simultaneously on opposite sides of the globe?
Who controls them?</p>

<p>Answers those questions, you'll realize "they" know it's not Co2, and you'll know it too.</p>

CC BY-SA 4.0
2020-01-17T17:45:08.087Z
Are you denying the greenhouse effect of CO2? (just to start with)
luchonacho
CC BY-SA 4.0
2020-01-17T23:09:53.010Z
@AHBeing I think, you vastly underestimate the neutron flux in the area where you operate your computer.
klanomath
CC BY-SA 4.0
2020-01-18T01:57:33.813Z
@luchonacho, there is a reason it's called the "Greenhouse" effect. It's used to make plants grow faster, healthier in a shorter period of time. If you've ever spent any time in a greenhouse the first thing that hits you is the feeling that you need to "chew the air" before you breathe it in. That being said, as it pertains to "climate change",  G00gle is an "echo chamber", try using a different search engine, shockingly the results are less biased, example; [Ice Core Samples ](http://21sci-tech.com/2006_articles/IceCoreSprg97.pdf) It's difficult to know the truth when it's suppressed :/
A.H.Being
CC BY-SA 4.0
2020-01-17T17:22:57.193Z
2020-01-18T15:38:36.327Z
2020-01-18T15:38:36.327Z
A.H.Being
<p>There are indeed a lot of positive feedback mechanisms, i.e. a warm climate leads to a warmer climate. From <a href="https://en.wikipedia.org/wiki/Climate_change_feedback" rel="noreferrer">this Wikipedia article</a>, they are:</p>
<ul>
<li>Carbon cycle feedbacks</li>
<li>Cloud feedback</li>
<li>Gas release</li>
<li>Ice-albedo feedback</li>
<li>Water vapor feedback</li>
</ul>
<p>However, there are also a few negative feedbacks (same source):</p>
<ul>
<li>Blackbody radiation</li>
<li>Carbon cycle</li>
<li>Lapse rate</li>
<li>Impacts on humans</li>
</ul>
<p>Now the question is: what is the net budget between positive and negative feedbacks? To assess this, climatologists use some metrics, the main ones being &quot;transient climate response&quot; (TCR) and &quot;equilibrium climate sensitivity&quot; (ECS). From <a href="https://doi.org/10.1038/ngeo3017" rel="noreferrer">Knutti et al. (2017)</a>:</p>
<blockquote>
<p>TCR is defined as the global mean surface warming at the time of
doubling of CO<span class="math-container">$_2$</span> in an idealized 1% yr<span class="math-container">$^{−1}$</span> CO<span class="math-container">$_2$</span> increase
experiment, but is more generally quantifying warming in response to a
changing forcing prior to the deep ocean being in equilibrium with the
forcing. Based on state-of-the-art climate models, and instrumentally
recorded warming in response to CO<span class="math-container">$_2$</span> and other anthropogenic and
natural forcings, the Intergovernmental Panel on Climate Change's
Fifth Assessment Report (IPCC AR5) assessed that the transient climate
response is 'likely' (&gt;66% probability) to be in the range of 1 °C to
2.5 °C.</p>
<p>By contrast, the equilibrium climate sensitivity (ECS) is defined as
the warming response to doubling CO<span class="math-container">$_2$</span> in the atmosphere relative to
pre-industrial climate, after the climate reached its new equilibrium,
taking into account changes in water vapour, lapse rate, clouds and
surface albedo. [...] The estimated range of ECS has not changed much
despite massive research efforts. The IPCC assessed that it is
'likely' to be in the range of 1.5 °C to 4.5 °C.</p>
</blockquote>
<p>Which basically means that the climate will get warmer in the future, until it will eventually reach some kind of equilibrium.</p>

CC BY-SA 4.0
2020-01-15T09:16:08.923Z
The blackbody radiation seems to me to be a very strong limit preventing a vicious circle from continuing.  T^4 is a very strong feedback indeed, and I am glad of it! ;o)
Dikran Marsupial
CC BY-SA 4.0
2020-01-15T09:30:13.713Z
@DikranMarsupial The T in T^4 is the average world temperature, in Kelvin. If the temperature rose so much that this effect would prevent any further warming, we'd already be in a hothouse; we _must_ hope for _all_ effects to stop global warming before the planet becomes uninhabitable for vertebrates in general due to inadequate cooling.
toolforger
CC BY-SA 4.0
2020-01-15T14:43:51.450Z
@DikranMarsupial But surely that feedback effect wasn't enough in the past to keep total change within the habitable temperature zone. Can't see why it might be different this time. In other words, this effect wasn't strong enough in the past, and might thus not be so this time either.
luchonacho
CC BY-SA 4.0
2020-01-15T15:05:56.603Z
@DikranMarsupial To follow up on toolforgers comment: a whopping 10 degrees  rise in average temperature from 10C to 20C would only result in an (293/283)**4 = 1.15 increase in blackbody radiation.
Jan Doggen
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2020-01-15T16:31:32.433Z
@JanDoggen Thanks. That was the point of my comment.
luchonacho
CC BY-SA 4.0
2020-01-16T08:07:08.157Z
Yes, but that is quite a lot.  Surface radiation is about 400Wm^2 but CO2 radiative forcing is only about 1.5 Wm^2, so a change of 1.15 in radiated energy would be a difference of 60 Wm^2.  It could be that I have missed something (I am not an expert), but as I understood it, the reason CO2 has a substantial effect is that it makes small modulation of a vast energy flux.  SB is a change in the vast flux.
Dikran Marsupial
CC BY-SA 4.0
2020-01-16T08:40:20.440Z
BTW "before the planet becomes uninhabitable for vertebrates" seems like hyperbole to me, I don't think that is consistent with the IPCC reports.
Dikran Marsupial
CC BY-SA 4.0
2020-01-16T15:01:30.807Z
@DikranMarsupial How about "_before our highly-integrated global economy breaks down_"? That is almost as scary, if you ask me.
Oscar Bravo
CC BY-SA 4.0
2020-01-16T18:05:29.917Z
@OscarBravo I think that is probably hyperbole as well, but if you have some evidence that is possible (e.g. wg2 or wg3 reports) then I am happy to listen.
Dikran Marsupial
CC BY-SA 4.0
2020-01-17T08:01:32.487Z
Look at Figure 9.43 (on page 819 of the IPCC AR5 WG1 report) https://www.ipcc.ch/site/assets/uploads/2018/02/Fig9-43-1-1024x572.jpg It shows that the Planck feedback is by far the strongest negative feedback according to all climate models (about -3Wm^-2C^-1 - more than three times the magnitude of lapse rate feedback, the next strongest).
Dikran Marsupial
CC BY-SA 4.0
2020-01-17T11:27:59.413Z
@DikranMarsupial How drastic the collapse is and how much/many will survive is certainly questionable. The fact that there will be some impact and that it will hit some areas harder than others is undeniable - the potential ripple on effects from that are hard to predict and could range from "easily handled" to "collapse of civilisation" level. Personally I'd rather avoid even a slim chance of "collapse of civilisation" if we can :)
Tim B
CC BY-SA 4.0
2020-01-17T11:44:39.417Z
@TimB indeed, my point is that hyperbole is likely to be counter-productive.  The most likely eventuality is bad enough already that we should be doing something about it anyway.  But the planet being uninhabitable for verebrates is simply not going to happen and a collapse of the *global* economy is also rather unlikely AFAICS.  Rational policy requires accurate information and balanced consideration of the risks, costs and benefits.
Dikran Marsupial
CC BY-SA 4.0
2020-01-17T12:06:32.653Z
@DikranMarsupial "Collapse of the global economy" might not happen, but an extended period of stagnation, uneven development, and social instability, driven by allocative inefficiencies, wasted resources, rebuilding activities (i.e. stabilising rather than advancing state of affairs), migration, and etc. The costs will be large, and specially for the poorest. BTW, linking to the IPCC report in a previous comment of you, for further details and analysis of feedback, would be a great addition to the answer imo.
luchonacho
CC BY-SA 4.0
2020-01-17T12:08:43.637Z
@luchonacho indeed, it is a much stronger argument expressed in that way without the hyperbole. +1
Dikran Marsupial
CC BY-SA 4.0
2020-01-17T12:09:55.710Z
@DikranMarsupial I just saw it's not your answer! Maybe you can add a new one elaborating on that report you linked? I think it would be a shame it got lost in comments that are likely to be removed.
luchonacho
CC BY-SA 4.0
2020-01-17T12:22:45.953Z
@luchonacho I'd rather leave it to somebody with real expertise on radiative physics, I have a little knowledge of the carbon cyclist, but I am basically a statistician/computer scientist.  The basic point I wanted to make is that the T^4 Planck feedback is quite strong, and thankfully makes a runaway/vicious circle very difficult.
Dikran Marsupial
CC BY-SA 4.0
2020-01-14T11:04:44.913Z
2020-01-14T11:04:44.913Z
2020-06-18T08:25:19.090Z
Jean-Marie Prival
<p>

<p>My question refers to the current process of climate change. CO<sub>2</sub> is rising, which leads to the greenhouse effect, which raises temperatures. This leads to more wildfires, which reduces number of trees, increasing CO<sub>2</sub> and reducing CO<sub>2</sub> capacity absorption. Ice caps start to melt, which reduces sunlight reflection (less snow), trapping more heat on atmosphere. Water rises, taking over land and trees, further enhancing the CO<sub>2</sub> absorption capacity. Oceans acidify, lowering their CO<sub>2</sub> absorption capacity too. Etc etc.</p>

<p>It seems the process of climate change is a "vicious circle", with a lot of feedback loops reinforcing the trends.</p>

<p><strong>Is this the case?</strong> Are there counteracting forces that go against this circle?</p>

<p>Related questions which imo do not provide an answer to this one: <a href="https://earthscience.stackexchange.com/questions/13464/is-global-warming-a-linear-process">here</a>, <a href="https://earthscience.stackexchange.com/questions/7737/global-warming-cycles">here</a>.</p>

CC BY-SA 4.0
2020-01-14T10:57:19.170Z
+1 : I've done a general answer, but a more detailed one going into some of the feedbacks would be great!
Semidiurnal Simon
CC BY-SA 4.0
2020-01-16T02:31:08.047Z
Not enough for an answer, but: Some of the positive feedback  loops have a "tipping point", a threshold beyond which the effect becomes a "runaway" effect. Examples include the abrupt change of albedo when the sea ice has melted all the way so that the dark water is exposed, leading to higher water temperatures and consequently more ice melting, or the thawing permafrost releasing large amounts of methane leading to more thawing.
Peter - Reinstate Monica
<climate-change>
Is climate change a vicious circle?
luchonacho
# Is climate change a vicious circle?

(Asked by: username_0 on 2020-01-14)

My question refers to the current process of climate change. CO2 is rising, which leads to the greenhouse effect, which raises temperatures. This leads to more wildfires, which reduces number of trees, increasing CO2 and reducing CO2 capacity absorption. Ice caps start to melt, which reduces sunlight reflection (less snow), trapping more heat on atmosphere. Water rises, taking over land and trees, further enhancing the CO2 absorption capacity. Oceans acidify, lowering their CO2 absorption capacity too. Etc etc.

It seems the process of climate change is a "vicious circle", with a lot of feedback loops reinforcing the trends.

**Is this the case?** Are there counteracting forces that go against this circle?

Related questions which imo do not provide an answer to this one: [here](https://earthscience.stackexchange.com/questions/13464/is-global-warming-a-linear-process), [here](https://earthscience.stackexchange.com/questions/7737/global-warming-cycles).

**Tags:** climate-change

> **Comments:**
> **username_1**: +1 : I've done a general answer, but a more detailed one going into some of the feedbacks would be great!  
> **username_2**: Not enough for an answer, but: Some of the positive feedback  loops have a "tipping point", a threshold beyond which the effect becomes a "runaway" effect. Examples include the abrupt change of albedo when the sea ice has melted all the way so that the dark water is exposed, leading to higher water temperatures and consequently more ice melting, or the thawing permafrost releasing large amounts of methane leading to more thawing.  

---

## 6 answers

### Answer by username_11 on 2020-01-14. Score: 42 | Accepted answer

There are indeed a lot of positive feedback mechanisms, i.e. a warm climate leads to a warmer climate. From [this Wikipedia article](https://en.wikipedia.org/wiki/Climate_change_feedback), they are:

* Carbon cycle feedbacks
* Cloud feedback
* Gas release
* Ice-albedo feedback
* Water vapor feedback

However, there are also a few negative feedbacks (same source):

* Blackbody radiation
* Carbon cycle
* Lapse rate
* Impacts on humans

Now the question is: what is the net budget between positive and negative feedbacks? To assess this, climatologists use some metrics, the main ones being "transient climate response" (TCR) and "equilibrium climate sensitivity" (ECS). From [Knutti et al. (2017)](https://doi.org/10.1038/ngeo3017):

> TCR is defined as the global mean surface warming at the time of
> doubling of CO$\_2$ in an idealized 1% yr$^{−1}$ CO$\_2$ increase
> experiment, but is more generally quantifying warming in response to a
> changing forcing prior to the deep ocean being in equilibrium with the
> forcing. Based on state-of-the-art climate models, and instrumentally
> recorded warming in response to CO$\_2$ and other anthropogenic and
> natural forcings, the Intergovernmental Panel on Climate Change's
> Fifth Assessment Report (IPCC AR5) assessed that the transient climate
> response is 'likely' (>66% probability) to be in the range of 1 °C to
> 2.5 °C.
>
> By contrast, the equilibrium climate sensitivity (ECS) is defined as
> the warming response to doubling CO$\_2$ in the atmosphere relative to
> pre-industrial climate, after the climate reached its new equilibrium,
> taking into account changes in water vapour, lapse rate, clouds and
> surface albedo. [...] The estimated range of ECS has not changed much
> despite massive research efforts. The IPCC assessed that it is
> 'likely' to be in the range of 1.5 °C to 4.5 °C.

Which basically means that the climate will get warmer in the future, until it will eventually reach some kind of equilibrium.

> **Comments:**
> **username_12**: The blackbody radiation seems to me to be a very strong limit preventing a vicious circle from continuing.  T^4 is a very strong feedback indeed, and I am glad of it! ;o)  
> **username_13**: @username_12 The T in T^4 is the average world temperature, in Kelvin. If the temperature rose so much that this effect would prevent any further warming, we'd already be in a hothouse; we _must_ hope for _all_ effects to stop global warming before the planet becomes uninhabitable for vertebrates in general due to inadequate cooling.  
> **username_0**: @username_12 But surely that feedback effect wasn't enough in the past to keep total change within the habitable temperature zone. Can't see why it might be different this time. In other words, this effect wasn't strong enough in the past, and might thus not be so this time either.  
> **username_14**: @username_12 To follow up on toolforgers comment: a whopping 10 degrees  rise in average temperature from 10C to 20C would only result in an (293/283)**4 = 1.15 increase in blackbody radiation.  
> **username_0**: @username_14 Thanks. That was the point of my comment.  
> **username_12**: Yes, but that is quite a lot.  Surface radiation is about 400Wm^2 but CO2 radiative forcing is only about 1.5 Wm^2, so a change of 1.15 in radiated energy would be a difference of 60 Wm^2.  It could be that I have missed something (I am not an expert), but as I understood it, the reason CO2 has a substantial effect is that it makes small modulation of a vast energy flux.  SB is a change in the vast flux.  
> **username_12**: BTW "before the planet becomes uninhabitable for vertebrates" seems like hyperbole to me, I don't think that is consistent with the IPCC reports.  
> **username_15**: @username_12 How about "_before our highly-integrated global economy breaks down_"? That is almost as scary, if you ask me.  
> **username_12**: @username_15 I think that is probably hyperbole as well, but if you have some evidence that is possible (e.g. wg2 or wg3 reports) then I am happy to listen.  
> **username_12**: Look at Figure 9.43 (on page 819 of the IPCC AR5 WG1 report) https://www.ipcc.ch/site/assets/uploads/2018/02/Fig9-43-1-1024x572.jpg It shows that the Planck feedback is by far the strongest negative feedback according to all climate models (about -3Wm^-2C^-1 - more than three times the magnitude of lapse rate feedback, the next strongest).  
> **username_16**: @username_12 How drastic the collapse is and how much/many will survive is certainly questionable. The fact that there will be some impact and that it will hit some areas harder than others is undeniable - the potential ripple on effects from that are hard to predict and could range from "easily handled" to "collapse of civilisation" level. Personally I'd rather avoid even a slim chance of "collapse of civilisation" if we can :)  
> **username_12**: @username_16 indeed, my point is that hyperbole is likely to be counter-productive.  The most likely eventuality is bad enough already that we should be doing something about it anyway.  But the planet being uninhabitable for verebrates is simply not going to happen and a collapse of the *global* economy is also rather unlikely AFAICS.  Rational policy requires accurate information and balanced consideration of the risks, costs and benefits.  
> **username_0**: @username_12 "Collapse of the global economy" might not happen, but an extended period of stagnation, uneven development, and social instability, driven by allocative inefficiencies, wasted resources, rebuilding activities (i.e. stabilising rather than advancing state of affairs), migration, and etc. The costs will be large, and specially for the poorest. BTW, linking to the IPCC report in a previous comment of you, for further details and analysis of feedback, would be a great addition to the answer imo.  
> **username_12**: @username_0 indeed, it is a much stronger argument expressed in that way without the hyperbole. +1  
> **username_0**: @username_12 I just saw it's not your answer! Maybe you can add a new one elaborating on that report you linked? I think it would be a shame it got lost in comments that are likely to be removed.  
> **username_12**: @username_0 I'd rather leave it to somebody with real expertise on radiative physics, I have a little knowledge of the carbon cyclist, but I am basically a statistician/computer scientist.  The basic point I wanted to make is that the T^4 Planck feedback is quite strong, and thankfully makes a runaway/vicious circle very difficult.  

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### Answer by username_1 on 2020-01-14. Score: 20

You've correctly identified a number of individual mechanisms which form "vicious circles". They're more formally known as "positive feedbacks". As you've noted, loss of albedo (reflectivity) from melted ice is one. Some of the others you've listed are a bit more complex - e.g. trees will regrow, algae in oceans are quite effective at removing CO2, etc.

One of the big concerns that people have is that if some of the larger positive feedback mechanisms get going - e.g. the melting of frozen methane on the seafloor - then it will impossible for anything that mankind does to stop it, and even if we completely stop emitting greenhouse gases we'll get pushed to a much warmer climate.

There are also negative feedback mechanisms. For example, a warmer atmosphere is likely to have more clouds, which will reflect more sunlight. But the warmer atmosphere can also hold more water vapour, which itself is a greenhouse gas, which is a positive feedback.

One of the reasons that climate science is hard is that all of these positive and negative feedbacks interact, making the earth system a very complex one.

> **Comments:**
> **username_1**: @ebv two of those are things I already mentioned....  
> **username_1**: @ebv fair enough! I'm not going to edit into here, because there's a good, and more comprehensive answer, already. But thanks :)  
> **username_3**: Climate science isn't hard! Don't be ridiculous. These complex mechanisms and cross-interacting factors? Nonsense. All you _really_ need is a little bar chart with some cherry-picked temperature data from the last hundred years or so, share it on Facebook, and presto! You're an expert. Duh.  
> **username_4**: Ad melting of frozen methane - it's not that humans couldn't do anything to stop the planet from warming, it's just the point where reducing the carbon dioxide production isn't going to be enough (i.e. even if we cut all carbon dioxide emissions, the methane will produce as much or more as we used to). We can still do things like add particulates or sulphur dioxides to the atmosphere, produce radiators that reflect most light but have high emission in the right IR range etc. The difference is we're no longer in the "let's go back mode", but exploring new climate territory :)  

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### Answer by username_5 on 2020-01-18. Score: 3

Climate Change definitely seem like a vicious cycle on a decadal scale. As other answers have pointed out there are numerous positive [feedbacks](https://climate.nasa.gov/nasa_science/science/) such as:

1. Warmer atmosphere holding more water vapor (which is a GHG) leading to more clouds
2. Reduced snow cover reflecting less solar radiation (lower albedo)
3. Reduced snow and ice cover on land leading to faster release of previously "locked up" methane in permafrost
4. Warming increases decomposition of organic matter in general ( particularly worrying in previously waterlogged area e.g. peatland)

However, this "vicious cycle" will likely decrease in strength over time, for reasons like blackbody radiation mentioned in the other answer. "Potential" full or partial reversal of the cycle, however, is dependant on biospheric feedbacks (blackbody radiation can only stabilize). Simply put, organisms collectively tend to stabilize environmental variables within certain ranges for homeostasis sake (humans are outliers, unfortunately), especially for bioresources like carbon dioxide and methane. I argue from an evolutionary standpoint, that **most biospheric negative feedbacks** (which is in essence ecological responses refined through eons of large-scale nutrient imbalance selection experiment) **operate on a larger timescale than the aforementioned positive feedbacks** because throughout Earth's history, it is unlikely that the Earth has experienced the current fast rate of warming that results in effective selection dynamics (you may argue we had seen that but massive and scarce pulse disaster is an example of ineffective selection that doesn't lead to meaningful adaptation and act more like lottery, whereas continuous and gradual impact is the best form of selection pressure). If there exists a biospheric "negative feedback" mechanism that leads to very fast cooling, in itself it would not be sustainable (just like fast warming) and would be weed out by evolution.

So enough of evolutionary theory, how does an ecological negative feedback work (approximately)?

Carbon dioxide fertilization and warming would favor and select the most efficient primary producers within the community repository (those who can use CO2 for growth and reproduction efficiently would be able to expand in numbers). Globally, in ocean, it would be r-strategists (phytoplanktons) that can grow and reproduce quickly whereas on land it would be trees that have conquered the limitation of height in primary production (I'm talking about in general what would be favored, there would be local variation no doubt). Also, note that two of the fastest flowing nutrient cycles i.e. C and N cycles are to some extent coupled and increased N deposition has indeed been shown to reinforce carbon sequestration (there is solid evidence of the increase in concentration of N compounds in the atmosphere which would deposit back to the environment when rained down.)

It should be noted that while the primary producers have some time to enjoy the "feast", the increased input of organic matter (OM) in the ecosystems (from primary producers) in turns constitute another selection pressure to select the most efficient consumers and decomposers. The duo processes would get closer and closer to an equilibrium eventually, but it is not likely to be the same state we had seen in pre-industrial time.

So yes, in the "short-term" i.e. decades (which in itself is considered "long" relative to human lifespan), climate change does seem like a vicious cycle but on a longer-term it would likely find its "peace" through wax and wanes of biospheric responses.


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### Answer by username_6 on 2020-02-15. Score: 2

The wording of the question suggests that it is asking about what climate scientists refer to as a run-away feedback. There are, and always have been, positive feed-backs in the climate system, but these are balanced by the major stabilizing effect of emitted infra-red radiation: the simple fact that the Earth emits more heat to space when it is warmer, and this tends to counter-act and heating effect.

Hence, our climate behaves like a benign, self-stabilizing system, not one that spirals out of control as soon as it is perturbed.

For instance, a 1 degree Celcius warming will increase the amount of water vapor in the atmosphere by about 6-7% (because hotter air can carry more water -- see, for examnple, [skeptical science](https://skepticalscience.com/print.php?r=44)). Water vapor is a greenhouse gas, so this extra water vapor will create extra heating of around 2.2 W m-2 ([AGU Report](https://phys.org/news/2014-03-effect-vapor-climate.html)). At the same time, an extra degree of Celcius means that the Earth is radiating more heat to space. This can be estimated from the Stephan-Boltzman law (maths omitted) and it turns out that 1 degree Celcius of warming results in roughly an additional 6 W m-2 being emitted to space. The extra cooling effect (6 W m-2) is greater than the feedback effect (2.2 W m-2) so the net effect is that when the Earth's climate is subjected to a temporary warming it will cool back to its equilibrium.

**The reason why we see exponential warming now is not because of a vicious feedback, it is because we are applying an exponentially increasing forcing.**

However, there is no absolute physical law which says that the stabilizing effect of emitted infrared radiation always has to win over the feed-backs. There is a concern that rising temperatures might strengthen the feed-backs so much that they overwhelm the stabilizing effects, leading to an unstoppable run-away feedback which could well wipe out all mammals, us included. That would be vicious. It has to be said, of course, that there are no credible predictions of a run-away feedback anytime soon -- the debate there is whether our models would be able to spot one before it happened.


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### Answer by username_7 on 2020-01-14. Score: -2

Yes, you are quite right, it does create a vicious circle, though not quite as vicious as some might think. As you suggest, there are natural forces which ameliorate the effects of this vicious circle.

Most of the woodland burned by these fires regenerates, though this takes a while. Where it doesn't regenerate, its place is usually taken by agriculture, which also consumes CO2, but less effectively than trees.

The de-icing of the NW and NE Passages will allow ships to take short cuts to their destinations and thus use less fuel, which lowers CO2 emissions.

The increased CO2 in the atmosphere will allow vegetation, both natural and agricultural, to grow more efficiently by perhaps a few percent. This applies not only in the rainforest, but in the oceans where the majority of photosynthesis takes place (in this context I include all photosynthetic marine organisms, not just vegetation as we normally think of it).

Just as there are more factors which create a vicious circle, so there are more ameliorating factors which lessen it, but not enough to prevent an increase in the vicious circle you speak of in your question.

> **Comments:**
> **username_8**: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/103333/discussion-on-answer-by-username_7-username_7-is-climate-change-a-vicious-circle), minus previously deleted comments. Note that the [Code of Conduct](https://stackoverflow.com/conduct) still applies in chat: keep it civil.  

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### Answer by username_9 on 2020-01-17. Score: -7

It isn't Co2 (sorry I know that's likely unpopular for most to hear), it's (primarily) the sun.

Real quick, rising Co2 doesn't cause wildfires, trees love Co2, visit a greenhouse. Wildfires are a result of (bleep holes) running around lighting fires. Look it up, nearly 200 people arrested so far in Australia for arson.

Ocean rise prediction data (focused on Co2) fails to account for increased plant intake due to plant growth explosion. Similarly, population reduction doesn't account for the 12 gallons of water that makes up an average male. Reduce population by 1 million average men, increase water levels by approx 12 million gallons.

The ice was always supposed to melt, it's a byproduct of a catastrophe.

However, the long answer to your point is technically "classified" by the U.S. military and a secret. It was part of my training in the USAF, couldn't do my job unless they told me. What's classified is less the information but more our comprehension of it. Foreign nations know of it, they just don't have the big picture. Once you know, Climate Change is literally a hoax as it's currently being peddled.

This is one entity that monitors the real source of our "Climate Change" [NOAA](https://www.swpc.noaa.gov/products/planetary-k-index)

This site also has some good info; [Earth's Electromagnetic Field](https://web.ua.es/docivis/magnet/earths_magnetic_field2.html)

My previous source was NORAD, I'm retired now, can't access it so, NOAA is the closest thing I've found publically available. We referred to it as "Geo-Planetary Index", it was/is monitored by the "minute" because it's that critical to success of the military's mission.

I don't know if politicians know the truth but some manufacturers clearly do. One example; [ECC\_memory](https://en.wikipedia.org/wiki/ECC_memory)

I'm not a fan of using Wiki however, the author of this excerpt from the above link knows what I know; "research has shown that the majority of one-off soft errors in DRAM chips occur as a result of background radiation, chiefly neutrons from cosmic ray secondaries, which may change the contents of one or more memory cells or interfere with the circuitry used to read or write to them.[3] Hence, the error rates increase rapidly with rising altitude; for example, compared to sea level, the rate of neutron flux is 3.5 times higher at 1.5 km and 300 times higher at 10–12 km (the cruising altitude of commercial airplanes).[4] As a result, systems operating at high altitudes require special provision for reliability."

If the public really wants to have an appreciable effect on the temperature, find a way to make the roadways, solar panels white/reflective. Plant more green things...

Edit/Update: Just keep this in mind, Co2 not being the cause isn't my "opinion". It doesn't matter if you have a PhD in "Climate Studies", it doesn't change reality.

More things to consider:

How many colliders are on the planet? (Hint: 40% are underground/classified i.e. don't exist, why?)
What alternative things are they used for beyond scientific study?
When do they fire them?
Where are they geo located, what's unique about their placement?
Why are they often fired simultaneously on opposite sides of the globe?
Who controls them?

Answers those questions, you'll realize "they" know it's not Co2, and you'll know it too.

> **Comments:**
> **username_0**: Are you denying the greenhouse effect of CO2? (just to start with)  
> **username_10**: @username_9 I think, you vastly underestimate the neutron flux in the area where you operate your computer.  
> **username_9**: @username_0, there is a reason it's called the "Greenhouse" effect. It's used to make plants grow faster, healthier in a shorter period of time. If you've ever spent any time in a greenhouse the first thing that hits you is the feeling that you need to "chew the air" before you breathe it in. That being said, as it pertains to "climate change",  G00gle is an "echo chamber", try using a different search engine, shockingly the results are less biased, example; [Ice Core Samples ](http://21sci-tech.com/2006_articles/IceCoreSprg97.pdf) It's difficult to know the truth when it's suppressed :/  

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