5 ms·

So let me get this off my chest before I start: I fully believe mankind has influenced the climate. That being said I find doom and gloom predictions of runawa

by cletus 7y ago

So let me get this off my chest before I start: I fully believe mankind has influenced the climate. That being said I find doom and gloom predictions of runaway greenhouse effects... problematic. After all, if this is possible and the earth has been much warmer, why hasn’t this happened already? I just don’t believe we’re that close to a tipping point. Climate is complicated and the earth can’t have been livable for billions of years without some balancing factors, right?

jdnenej 7y ago
The timescales are completely different. Past climate changes have been on the scale of hundreds of thousands of years. Now we are seeing it on the scale of a hundred years. Life on Earth will most likely exist after climate change but it won't be any of the life as we know it.
- ncmncm 7y ago
  Most of life will adapt. Thousands of species will go extinct, probably not including us, but including the other apes. Likely, billions will die, only a few million by nuclear incineration. Most will starve. The stragglers, probably mostly primitives plus a bunch of rich bastards, will repopulate the Earth and pick up in what is left.
- Yetanfou 7y ago
  Nonsense, simply put. Past climate change has been driven by all sorts of factors, from bolide impacts through volcanic eruptions to large-scale forest fires. In several cases these changes came abruptly, far more so than the change caused by human activity. Also, the previous interglacial period was warmer than the current. During the Viking age wine was being grown in Scandinavia. The Roman empire arose and thrived during a warmer period, its fall coincided with a marked cooling which only lifted at the end of the 'little ice age' - when the Thames was frozen and all those famous Dutch masters painted scenes of Dutchmen and -women skating over canals and lakes. May I suggest looking back into the rich history of doomsaying? All the way back to Malthus who, even though he was wrong in his prediction of the planet being incapable of feeding more than a billion human beings, actually did touch upon the problem of overpopulation which is a larger threat than any of the ones subsequently dragged up by the latest crop of doomsayers. To name a few causes more worthy of attention than the current CO₂ hysteria: - Population growth. Malthus thought the planet could not feed more than 1 billion people. He was wrong, he failed to foresee the industrial revolution which makes it possible to feed 7 billion and has the potential to feed the 10 billion which is expected to be the number of humans reached before population starts to decline. - That industrial revolution has given its blessings but it also came with the curse of large-scale environmental pollution. While these problems are being tackled in some parts of the world the same can unfortunately not be said about others. - Population growth also leads to increased migration which has the potential to lead to increased conflicts which has the potential to lead to the undoing of many of the efforts currently put in the negation of the negative aspects of the industrial revolution. People at war have different priorities from those at peace. Just like with the doomsayers it makes sense to use history as a guide here. Genghis Khan (who, when seen in the percentage of the world population killed (estimates range from 5% to ~10%) still reigns supreme as the biggest killer of them all [1]) started a wave of migration which was felt all the way to the west and north of Europe with one displaced population on the move jostling for space with the next. So, what can be done about these? The population growth will, bar the intervention of any catastrophic events, probably follow the predicted curve with the total world population reaching about 10 billion people somewhere in the 2100s. It took the west more than a century to realise than unbridled industrial growth and the accompanying pollution was a recipe for disaster, hopefully the now industrialising parts of the world will have learned this lesson well so they don't continue to make the same mistakes. Migration will lead to conflicts, this is probably unavoidable. It can only be hoped that these conflicts don't escalate too far. [1] https://en.wikipedia.org/wiki/Destruction_under_the_Mongol_Empire https://en.wikipedia.org/wiki/Destruction_under_the_Mongol_E...
  - ben_w 7y ago
    Every doomsayer who was right was either: 1. Listened to, or 2: part of a civilisation which no longer exists.
    - papermachete 7y ago
      Kaczynski is still alive.
  - ncmncm 7y ago
    There is no reason to suppose that the mass migrations will not lead to global thermonuclear war. We are already witnessing a rise of fascism in response to the barest beginning of that migration. Fascism always ends in genocide and war.
    - Yetanfou 7y ago
      Fascism has a specific meaning and should not be abused to indicate a state form which you find disagreeable. There have not been that many true fascist states, Italy under Mussolini and Spain under Franco are examples of such, Germany under the National Socialist party was variation on a fascist state. The Soviet Union under communist rule was not a fascist state although the ideologies have many similarities, the same goes for China under communist rule and the Russian Federation under Putin's oligarchy. Those who use the term fascist to indicate states like the United Kingdom under Boris Johnson or the United States of America under Donald Trump have no idea what fascism actually means. For one, it does not mean 'resistance against immigration from non-western states'. Here's a good start on what Fascism is, the definition of the doctrine as declared by its originator, Benito Mussolini. http://www.historyguide.org/europe/duce.html http://www.historyguide.org/europe/duce.html More can be found in Britannica's article on the subject: https://www.britannica.com/topic/fascism https://www.britannica.com/topic/fascism In short - and mostly from Britannica's definition, supported by Mussolini's words Fascism is characterised by an extreme militaristic nationalism, contempt for electoral democracy and political and cultural liberalism, a belief in natural social hierarchy and the rule of elites, and the desire to create a 'Volksgemeinschaft' (German: “people’s community”), in which individual interests would be subordinated to the good of the nation. Even shorter would be 'a militaristic nationalist dictatorial ideology which subjugates the individual for the (perceived) good of the nation'. It is such a close cousin to Communism and Islamism (and other similarly structured doctrines) that this short characterisation also applies to those ideologies.
tass 7y ago
In terms of scale of the planet’s life, the amount of time we are here is extremely short. The earth has been struck by at least one large rock resulting in mass extinctions. The planet recovered just fine along with the atmosphere, but there was significant change to the life left over. I also believe Earth will be fine this time, and there is some balancing factor that will eventually correct the changes to the atmosphere, but we and the majority of life on the planet will have difficulty surviving in the interim period.
- ncmncm 7y ago
  Humanity will not, like so many species, go extinct, but the radical population decline will not be comfortable, particularly for those who starve.
acidburnNSA 7y ago
It's not the temperature that kills. It's the rate of change. When organisms can't evolve fast enough with a changing environment, extinctions occur. We are causing a rate of change that is very significant. Not unprecedented (e.g. asteroid impact) but daunting nonetheless.
- ncmncm 7y ago
  We have every reason to believe that the human species will survive. Civilization, much less so.
remarkEon 7y ago
If I squint hard enough I can find a way to agree with you. I personally believe that we’re on the edge of a change in climate that will cause huge and potentially devastating problems. But I also think that most of the people that would agree with that statement don’t actually act like they agree with it. If you honestly think we have “12 years left” (as a certain congresswoman has said) you would be doing things like stocking arms, getting ready to grow your own vegetables and husband livestock, figuring out how barter economies would work in this apocalypse that is, allegedly, around the corner. Of course none of them are doing this.
- ben_w 7y ago
  The “12 years” thing: AFAIK, that’s “12 years to get moving, given how much political inertia we know we’ve got”, not “12 years to actually fix everything”.
- ncmncm 7y ago
  "Twelve years" is like every idiot cliffhanger movie, where the bomb is defused with two seconds to spare, and everything is suddenly fine again. Things will get continuously worse, and continue worsening long after the twelve years, even if we manage to do enough by then for civilization not to collapse. There is little point in setting up to grow vegetables when civilization collapses and roving bands of armed thugs raid anyone who seems to have anything they want. We will either avert disaster together, as a global society, or not at all. Growing vegetables is not a response. Do it anyway, if you like, just don't fool yourself that it improves your or anybody's chances.
shakna 7y ago
> After all, if this is possible and the earth has been much warmer, why hasn’t this happened already? We have two large-scale extinction events on record that may have been caused by or exacerbated by global warming: Tirassic-Jurassic Extinction event, and the Paleocene–Eocene Thermal Maximum (more a series of small-scale extinction events than a single large one). In world-scale timelines, humans haven't been around that long. > I just don’t believe we’re that close to a tipping point. Climate is complicated and the earth can’t have been livable for billions of years without some balancing factors, right? It wasn't. We've had many extinction level events. Humanity should be concerned about not becoming one.
mj370 7y ago
I agree. After adding all the uncertainties of the proxy data and our models (which we use to calculate temperature throughout Earth's history) it's not that sure change like this has never happened before, or that it is happening faster than ever before. There's no doubt we have impact, but it's not certain that it's the major driving force (though it may be, of course). Earth has several effects which periodically changes the climate. Those effects can coincide. At least that's what paleobiologist on a lecture I visited said. His appeal was: hold on to strict facts and take uncertainties into account. Don't hop on the doomsday wagon. We simply don't know enough about complexities of the climate.
- ncmncm 7y ago
  Uncertainty does not favor continued status quo. In fact even the climate models of decades ago have turned out to be dead on. There is no reason to believe the planet favors conditions we are used to, but our civilization depends on those conditions. Drive the planet to another norm, and civilization collapses, and billions starve. A minority survive and rebuild, and (who knows?) maybe learn something. In a thousand years, it will be as if nothing happened, except with a hell of a lot of species missing.
- pale-hands 7y ago
  Even if it were true that the climate has changed as much and as rapidly in the past, what difference does that make to our current situation? All but a few years in the next 3 centuries will be hotter than all but a few years in the past 3 centuries, and look at the impacts we're experiencing already. > There's no doubt we have impact, but it's not certain that it's the major driving force Just false. There is no reasonable doubt that human activity is responsible for about 100% (could be less, could be more) of the current warming.
- perchecrik 7y ago
  >After adding all the uncertainties of the proxy data and our models (which we use to calculate temperature throughout Earth's history) it's not that sure change like this has never happened before, or that it is happening faster than ever before. This is misleading. The rate of human injection of CO2 into the atmosphere has no analogue in the past, at least we've not found a similar excursion as yet. What effect this will have on the global climate system is inherently unpredictable, again, because we lack analogues from the past. What we do know is that global climate state changes have occurred rapidly; indeed, the whole Pleistocene is distinct in that the global climate system seems to have been in a boundary state in which it flips, sometimes within 50 years, from cold to warm, or the reverse. So that can serve as an analogue for how the global climate system can respond when perturbed. I say "have been" in the paragraph above because, in terms of atmospheric CO2 concentration, we've already exceeded any level observed during the Pleistocene. (And, not to belabor what I hope would be obvious by now, we have many lines of evidence that indicate with a high degree of certainty that it was human emission of CO2 in the last 150-200 years that has caused the spike in atmospheric concentrations.) Hence, researchers are looking to periods such as the Miocene and the Pliocene for a world that had continents in roughly the same configuration, but was much warmer, and, moreover, was warmer in a global pattern that fundamentally differs from that of the Pleistocene. We also have paleo-analogues for the effects of large increases in atmospheric CO2 concentration, and those are: acidification of oceans, ocean basin wide anoxia, local (confined, for example, to a particular ocean basin, or to a given depth range in oceans) and global extinctions, and interruption of the global oceanic thermo-haline circulation system. Another commenter stated that humans are as adaptable as roaches, and I'm afraid that this, too, may be a bit optimistic. In general, species resident at the highest trophic levels, with larger body sizes and habitat areal requirements, tend to be more vulnerable to change, and therefore to extinction, and thus tend to be much more ephemeral than smaller species in the fossil record.
FranzFerdiNaN 7y ago
The issue is that the earth is being brought out of balance within a few decades. This has rarely happened, and when it did happen (meteorites, volcanos etc) the consequences were bad. And yet we are arrogant enough to think we can pump billions of tons in the atmosphere without consequences. Our ancestors did enough to balance out a natural decrease in temperature that should have happened. And that was without a global industrial system. So of course what we do will massively influence the system. Going “I don’t believe things will be bad” is basically the same as “I don’t believe in climate change”. Both are an excuse not to do anything.
jacquesm 7y ago
> I just don’t believe we’re that close to a tipping point. Your beliefs matter not one tiny little bit. We either are, or we are not. If a large enough body of scientists in a field that is not my expertise appear to agree on something then I am going to believe them regardless of what I as a layperson in their field could come up with to say the opposite. Yes, it is complicated. The earth hasn't been livable for 'billions of years', and enough little people like us doing things that have never been done before and such balancing factors as there are can be upset. The Earth has many modes of existence, the current one is not a guaranteed one at all.
cletus 7y ago
Several replies brought up that the climate change caused by mankind is too quick that it is causing or will cause mass extinction. Now I don't necessarily dispute that we may already be in a mass extinction event. I do however think that practically speaking there's very little we can do about it at this point. But as for the abruptness of these changes consider [1]: > Each successively deeper ice layer represents a snapshot of Earth's climate history from the past, and together, the oxygen isotope record told a story of abrupt, millennial-scale climate shifts in air temperatures over Greenland between extremely cold stadial conditions and relatively mild interstadial periods during the last ice age (Figure 1) (Alley 2000, Alley et al. 2003). There are twenty-five of these distinct warming-cooling oscillations (Dansgaard 1984) which are now commonly referred to as Dansgaard-Oeschger cycles, or D-O cycles. One of the most surprising findings was that the shifts from cold stadials to the warm interstadial intervals occurred in a matter of decades, with air temperatures over Greenland rapidly warming 8 to 15°C 8-15C in "a matter of decades". So my point stands: we've had many abrupt climate changes, at least 15 in the last 100,000 years. So I remain skeptical that we're reaching some tipping point and we'll have anything approaching Venus-like runaway greenhouse effects. As well as these predictions not really gelling with historical events, I find the level of alarmism to be generally unhelpful. I realize there's probably good intent here and I'm sure many genuinely believe these slarmist predictions but I also think some of it is motivated the desire to get people to act. I think this has the opposite effect. I mean, if you're screwed anyway, why not enjoy yourself? [1]: https://www.nature.com/scitable/knowledge/library/abrupt-climate-change-during-the-last-ice-24288097/ https://www.nature.com/scitable/knowledge/library/abrupt-cli...
- atq2119 7y ago
  The real question for our human self-interest isn't about Venus-style runaway warning, it's whether civilization can survive any of these dramatic shifts.
macrolime 7y ago
I think the thinking is that it has happened a couple times before, perhaps causing mass extinctions. The earth is cycling between hotter and colder temperatures. There used to be no ice on the poles. Large changes to the environment kills lots of species and brings about many new ones.

by cletus 7y ago

jdnenej 7y ago

The timescales are completely different. Past climate changes have been on the scale of hundreds of thousands of years. Now we are seeing it on the scale of a hundred years. Life on Earth will most likely exist after climate change but it won't be any of the life as we know it.

ncmncm 7y ago
Most of life will adapt. Thousands of species will go extinct, probably not including us, but including the other apes. Likely, billions will die, only a few million by nuclear incineration. Most will starve. The stragglers, probably mostly primitives plus a bunch of rich bastards, will repopulate the Earth and pick up in what is left.
Yetanfou 7y ago
Nonsense, simply put. Past climate change has been driven by all sorts of factors, from bolide impacts through volcanic eruptions to large-scale forest fires. In several cases these changes came abruptly, far more so than the change caused by human activity. Also, the previous interglacial period was warmer than the current. During the Viking age wine was being grown in Scandinavia. The Roman empire arose and thrived during a warmer period, its fall coincided with a marked cooling which only lifted at the end of the 'little ice age' - when the Thames was frozen and all those famous Dutch masters painted scenes of Dutchmen and -women skating over canals and lakes. May I suggest looking back into the rich history of doomsaying? All the way back to Malthus who, even though he was wrong in his prediction of the planet being incapable of feeding more than a billion human beings, actually did touch upon the problem of overpopulation which is a larger threat than any of the ones subsequently dragged up by the latest crop of doomsayers. To name a few causes more worthy of attention than the current CO₂ hysteria: - Population growth. Malthus thought the planet could not feed more than 1 billion people. He was wrong, he failed to foresee the industrial revolution which makes it possible to feed 7 billion and has the potential to feed the 10 billion which is expected to be the number of humans reached before population starts to decline. - That industrial revolution has given its blessings but it also came with the curse of large-scale environmental pollution. While these problems are being tackled in some parts of the world the same can unfortunately not be said about others. - Population growth also leads to increased migration which has the potential to lead to increased conflicts which has the potential to lead to the undoing of many of the efforts currently put in the negation of the negative aspects of the industrial revolution. People at war have different priorities from those at peace. Just like with the doomsayers it makes sense to use history as a guide here. Genghis Khan (who, when seen in the percentage of the world population killed (estimates range from 5% to ~10%) still reigns supreme as the biggest killer of them all [1]) started a wave of migration which was felt all the way to the west and north of Europe with one displaced population on the move jostling for space with the next. So, what can be done about these? The population growth will, bar the intervention of any catastrophic events, probably follow the predicted curve with the total world population reaching about 10 billion people somewhere in the 2100s. It took the west more than a century to realise than unbridled industrial growth and the accompanying pollution was a recipe for disaster, hopefully the now industrialising parts of the world will have learned this lesson well so they don't continue to make the same mistakes. Migration will lead to conflicts, this is probably unavoidable. It can only be hoped that these conflicts don't escalate too far. [1] https://en.wikipedia.org/wiki/Destruction_under_the_Mongol_Empire https://en.wikipedia.org/wiki/Destruction_under_the_Mongol_E...
- ben_w 7y ago
  Every doomsayer who was right was either: 1. Listened to, or 2: part of a civilisation which no longer exists.
  - papermachete 7y ago
    Kaczynski is still alive.
- ncmncm 7y ago
  There is no reason to suppose that the mass migrations will not lead to global thermonuclear war. We are already witnessing a rise of fascism in response to the barest beginning of that migration. Fascism always ends in genocide and war.
  - Yetanfou 7y ago
    Fascism has a specific meaning and should not be abused to indicate a state form which you find disagreeable. There have not been that many true fascist states, Italy under Mussolini and Spain under Franco are examples of such, Germany under the National Socialist party was variation on a fascist state. The Soviet Union under communist rule was not a fascist state although the ideologies have many similarities, the same goes for China under communist rule and the Russian Federation under Putin's oligarchy. Those who use the term fascist to indicate states like the United Kingdom under Boris Johnson or the United States of America under Donald Trump have no idea what fascism actually means. For one, it does not mean 'resistance against immigration from non-western states'. Here's a good start on what Fascism is, the definition of the doctrine as declared by its originator, Benito Mussolini. http://www.historyguide.org/europe/duce.html http://www.historyguide.org/europe/duce.html More can be found in Britannica's article on the subject: https://www.britannica.com/topic/fascism https://www.britannica.com/topic/fascism In short - and mostly from Britannica's definition, supported by Mussolini's words Fascism is characterised by an extreme militaristic nationalism, contempt for electoral democracy and political and cultural liberalism, a belief in natural social hierarchy and the rule of elites, and the desire to create a 'Volksgemeinschaft' (German: “people’s community”), in which individual interests would be subordinated to the good of the nation. Even shorter would be 'a militaristic nationalist dictatorial ideology which subjugates the individual for the (perceived) good of the nation'. It is such a close cousin to Communism and Islamism (and other similarly structured doctrines) that this short characterisation also applies to those ideologies.

tass 7y ago

In terms of scale of the planet’s life, the amount of time we are here is extremely short. The earth has been struck by at least one large rock resulting in mass extinctions. The planet recovered just fine along with the atmosphere, but there was significant change to the life left over. I also believe Earth will be fine this time, and there is some balancing factor that will eventually correct the changes to the atmosphere, but we and the majority of life on the planet will have difficulty surviving in the interim period.

ncmncm 7y ago
Humanity will not, like so many species, go extinct, but the radical population decline will not be comfortable, particularly for those who starve.

acidburnNSA 7y ago

It's not the temperature that kills. It's the rate of change. When organisms can't evolve fast enough with a changing environment, extinctions occur. We are causing a rate of change that is very significant. Not unprecedented (e.g. asteroid impact) but daunting nonetheless.

ncmncm 7y ago
We have every reason to believe that the human species will survive. Civilization, much less so.

remarkEon 7y ago

If I squint hard enough I can find a way to agree with you. I personally believe that we’re on the edge of a change in climate that will cause huge and potentially devastating problems. But I also think that most of the people that would agree with that statement don’t actually act like they agree with it. If you honestly think we have “12 years left” (as a certain congresswoman has said) you would be doing things like stocking arms, getting ready to grow your own vegetables and husband livestock, figuring out how barter economies would work in this apocalypse that is, allegedly, around the corner. Of course none of them are doing this.

ben_w 7y ago
The “12 years” thing: AFAIK, that’s “12 years to get moving, given how much political inertia we know we’ve got”, not “12 years to actually fix everything”.
ncmncm 7y ago
"Twelve years" is like every idiot cliffhanger movie, where the bomb is defused with two seconds to spare, and everything is suddenly fine again. Things will get continuously worse, and continue worsening long after the twelve years, even if we manage to do enough by then for civilization not to collapse. There is little point in setting up to grow vegetables when civilization collapses and roving bands of armed thugs raid anyone who seems to have anything they want. We will either avert disaster together, as a global society, or not at all. Growing vegetables is not a response. Do it anyway, if you like, just don't fool yourself that it improves your or anybody's chances.

shakna 7y ago

> After all, if this is possible and the earth has been much warmer, why hasn’t this happened already? We have two large-scale extinction events on record that may have been caused by or exacerbated by global warming: Tirassic-Jurassic Extinction event, and the Paleocene–Eocene Thermal Maximum (more a series of small-scale extinction events than a single large one). In world-scale timelines, humans haven't been around that long. > I just don’t believe we’re that close to a tipping point. Climate is complicated and the earth can’t have been livable for billions of years without some balancing factors, right? It wasn't. We've had many extinction level events. Humanity should be concerned about not becoming one.

mj370 7y ago

I agree. After adding all the uncertainties of the proxy data and our models (which we use to calculate temperature throughout Earth's history) it's not that sure change like this has never happened before, or that it is happening faster than ever before. There's no doubt we have impact, but it's not certain that it's the major driving force (though it may be, of course). Earth has several effects which periodically changes the climate. Those effects can coincide. At least that's what paleobiologist on a lecture I visited said. His appeal was: hold on to strict facts and take uncertainties into account. Don't hop on the doomsday wagon. We simply don't know enough about complexities of the climate.

ncmncm 7y ago
Uncertainty does not favor continued status quo. In fact even the climate models of decades ago have turned out to be dead on. There is no reason to believe the planet favors conditions we are used to, but our civilization depends on those conditions. Drive the planet to another norm, and civilization collapses, and billions starve. A minority survive and rebuild, and (who knows?) maybe learn something. In a thousand years, it will be as if nothing happened, except with a hell of a lot of species missing.
pale-hands 7y ago
Even if it were true that the climate has changed as much and as rapidly in the past, what difference does that make to our current situation? All but a few years in the next 3 centuries will be hotter than all but a few years in the past 3 centuries, and look at the impacts we're experiencing already. > There's no doubt we have impact, but it's not certain that it's the major driving force Just false. There is no reasonable doubt that human activity is responsible for about 100% (could be less, could be more) of the current warming.
perchecrik 7y ago
>After adding all the uncertainties of the proxy data and our models (which we use to calculate temperature throughout Earth's history) it's not that sure change like this has never happened before, or that it is happening faster than ever before. This is misleading. The rate of human injection of CO2 into the atmosphere has no analogue in the past, at least we've not found a similar excursion as yet. What effect this will have on the global climate system is inherently unpredictable, again, because we lack analogues from the past. What we do know is that global climate state changes have occurred rapidly; indeed, the whole Pleistocene is distinct in that the global climate system seems to have been in a boundary state in which it flips, sometimes within 50 years, from cold to warm, or the reverse. So that can serve as an analogue for how the global climate system can respond when perturbed. I say "have been" in the paragraph above because, in terms of atmospheric CO2 concentration, we've already exceeded any level observed during the Pleistocene. (And, not to belabor what I hope would be obvious by now, we have many lines of evidence that indicate with a high degree of certainty that it was human emission of CO2 in the last 150-200 years that has caused the spike in atmospheric concentrations.) Hence, researchers are looking to periods such as the Miocene and the Pliocene for a world that had continents in roughly the same configuration, but was much warmer, and, moreover, was warmer in a global pattern that fundamentally differs from that of the Pleistocene. We also have paleo-analogues for the effects of large increases in atmospheric CO2 concentration, and those are: acidification of oceans, ocean basin wide anoxia, local (confined, for example, to a particular ocean basin, or to a given depth range in oceans) and global extinctions, and interruption of the global oceanic thermo-haline circulation system. Another commenter stated that humans are as adaptable as roaches, and I'm afraid that this, too, may be a bit optimistic. In general, species resident at the highest trophic levels, with larger body sizes and habitat areal requirements, tend to be more vulnerable to change, and therefore to extinction, and thus tend to be much more ephemeral than smaller species in the fossil record.

FranzFerdiNaN 7y ago

The issue is that the earth is being brought out of balance within a few decades. This has rarely happened, and when it did happen (meteorites, volcanos etc) the consequences were bad. And yet we are arrogant enough to think we can pump billions of tons in the atmosphere without consequences. Our ancestors did enough to balance out a natural decrease in temperature that should have happened. And that was without a global industrial system. So of course what we do will massively influence the system. Going “I don’t believe things will be bad” is basically the same as “I don’t believe in climate change”. Both are an excuse not to do anything.

jacquesm 7y ago

> I just don’t believe we’re that close to a tipping point. Your beliefs matter not one tiny little bit. We either are, or we are not. If a large enough body of scientists in a field that is not my expertise appear to agree on something then I am going to believe them regardless of what I as a layperson in their field could come up with to say the opposite. Yes, it is complicated. The earth hasn't been livable for 'billions of years', and enough little people like us doing things that have never been done before and such balancing factors as there are can be upset. The Earth has many modes of existence, the current one is not a guaranteed one at all.

cletus 7y ago

Several replies brought up that the climate change caused by mankind is too quick that it is causing or will cause mass extinction. Now I don't necessarily dispute that we may already be in a mass extinction event. I do however think that practically speaking there's very little we can do about it at this point. But as for the abruptness of these changes consider [1]: > Each successively deeper ice layer represents a snapshot of Earth's climate history from the past, and together, the oxygen isotope record told a story of abrupt, millennial-scale climate shifts in air temperatures over Greenland between extremely cold stadial conditions and relatively mild interstadial periods during the last ice age (Figure 1) (Alley 2000, Alley et al. 2003). There are twenty-five of these distinct warming-cooling oscillations (Dansgaard 1984) which are now commonly referred to as Dansgaard-Oeschger cycles, or D-O cycles. One of the most surprising findings was that the shifts from cold stadials to the warm interstadial intervals occurred in a matter of decades, with air temperatures over Greenland rapidly warming 8 to 15°C 8-15C in "a matter of decades". So my point stands: we've had many abrupt climate changes, at least 15 in the last 100,000 years. So I remain skeptical that we're reaching some tipping point and we'll have anything approaching Venus-like runaway greenhouse effects. As well as these predictions not really gelling with historical events, I find the level of alarmism to be generally unhelpful. I realize there's probably good intent here and I'm sure many genuinely believe these slarmist predictions but I also think some of it is motivated the desire to get people to act. I think this has the opposite effect. I mean, if you're screwed anyway, why not enjoy yourself? [1]: https://www.nature.com/scitable/knowledge/library/abrupt-climate-change-during-the-last-ice-24288097/ https://www.nature.com/scitable/knowledge/library/abrupt-cli...

atq2119 7y ago
The real question for our human self-interest isn't about Venus-style runaway warning, it's whether civilization can survive any of these dramatic shifts.

macrolime 7y ago

I think the thinking is that it has happened a couple times before, perhaps causing mass extinctions. The earth is cycling between hotter and colder temperatures. There used to be no ice on the poles. Large changes to the environment kills lots of species and brings about many new ones.