7 ms·

Here's the part that I don't get (and I would be afraid to admit to this in a non-anonymous setting among my peer group). I completely accept the evidence and

by ppod 8y ago

Here's the part that I don't get (and I would be afraid to admit to this in a non-anonymous setting among my peer group). I completely accept the evidence and the consensus that human action is causing global carbon levels and therefore temperature to rise. The part I don't get is what exactly happens to the planet, our species and other animals given say, a 2C rise by 2200. Say that's a 2 metre sea level rise. Ecosystems and societies are pretty robust to that level of change over 200 years. There would be very bad effects on some low-lying coastal cities, and the areas of the earth that are productive for different kinds of agriculture and habitats would change. This is bad and we should work to avoid it, but I think that we lose credibility when we speak of the end of civilisation, or even major threats to our normal way of life globally.

arnoooooo 8y ago
It's much more than a 2C rise and that will happer much faster than 2200. Even 2C is half an ice-age in magnitude, and it would be happening much faster. You can read my attempt at a primer, which details some of the consequences here : https://climate.btmx.fr https://climate.btmx.fr
- ThomPete 8y ago
  2C is the popularized number. In reality it's a range (0.8-2.6 for 2050 and 1.4-1.4-5.8 for 2100) and it's not certain how much humans can do about it or have to do with it (we are probably affecting it but how much is still an open question) We have been figthing to survive nature from the start. Ex. sea rise is not a problem that can't be solved just look at Holland. http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29 http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29
  - lozenge 8y ago
    > it's not certain how much humans can do about it or have to do with it (we are probably affecting it but how much is still an open question) What is your point in saying this? Everything always has uncertainties, but scientists and economists are in agreement there is enough known that we need large changes in energy use (which affects all sectors of the economy). That is found in the latest version of the report you linked to, or even the version you linked. The idea that Bangladesh can "solve" sea level rise because Holland can is laughable. Just look at these maps: http://www.realclimate.org/index.php/archives/2015/08/bjorn-lomborg-just-a-scientist-with-a-different-opinion/ http://www.realclimate.org/index.php/archives/2015/08/bjorn-...
    - ThomPete 8y ago
      Not sure there is any reason to debate someone who deliberately oversimplify what I say, call it laughable and then point to a highly biased website. Of course Holland and Bangladesh isn't the same situation so to call your own strawman laughable says a lot about where you are coming from in this. But against my better judgement I am still engaging in the hopes that you are in fact interested in hearing what my point is. Yes everything has uncertainties which would be good to remember in this debate as thats the difference between whether we are doomed or whether the climate will change as I has always done and we need to adjust to it. Instead of trying to claim that we know for a fact what the outcome is, how big our involvement in climate change is, how much we can do something about. Even the IPCC does not deal in such certainties and have toned down their doomsdaying over the years. That's important to keep in mind before we all jump on the "we are doomed" bandwagon. There are things we can do especially these days as we are much better at handling nature than we were 100 years ago which means that no matter how much of climate change is manmade we have a better chance of dealing with the consequences today than if those changes had happened 100 years ago.
- akvadrako 8y ago
  We don't know historical global temperatures well enough to say if anthropogenic warming is particularly fast. For example the Younger Dryas¹, about 15ky ago. The best estimate is global temp dropped 2-6° over 50 years and 1000 years later, did the opposite. Before that our data is so poor it's hard to distinguish between 1000 years and 1 year. [1] https://www.ncdc.noaa.gov/abrupt-climate-change/The%20Younger%20Dryas https://www.ncdc.noaa.gov/abrupt-climate-change/The%20Younge...
SwellJoe 8y ago
Conservative estimates put it at 2.8 degrees by 2100. Do you believe the temperature will stop rising in 2100? By what mechanism will it stop rising?
- ThomPete 8y ago
  Conservative put it at 1.4 http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29 http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29
  - SwellJoe 8y ago
    OK, will it stop at 1.4? If so, how?
    - deleted 8y ago
      [deleted]
  - lozenge 8y ago
    That's including the "radical action taken now" scenario (RCP), which anybody can see is not happening. It is also from AR3, the latest report is AR5, published over a decade later.
    - ThomPete 8y ago
      Here is the AR5 report which is toning down it's previous predictions from in other words things weren't as bad as claimed. It's not as black and white and the consequences are even more speculative. "Future climate will depend on committed warming caused by past anthropogenic emissions, as well as future anthropogenic emissions and natural climate variability. The global mean surface temperature change for the period 2016–2035 relative to 1986–2005 is similar for the four RCPs and will likely be in the range 0.3°C to 0.7°C (medium confidence). This assumes that there will be no major volcanic eruptions or changes in some natural sources (e.g., CH4 and N2O), or unexpected changes in total solar irradiance. By mid-21st century, the magnitude of the projected climate change is substantially affected by the choice of emissions scenario. {2.2.1, Table 2.1} Relative to 1850–1900, global surface temperature change for the end of the 21st century (2081–2100) is projected to likely exceed 1.5°C for RCP4.5, RCP6.0 and RCP8.5 (high confidence). Warming is likely to exceed 2°C for RCP6.0 and RCP8.5 (high confidence), more likely than not to exceed 2°C for RCP4.5 (medium confidence), but unlikely to exceed 2°C for RCP2.6 (medium confidence). {2.2.1} The increase of global mean surface temperature by the end of the 21st century (2081–2100) relative to 1986–2005 is likely to be 0.3°C to 1.7°C under RCP2.6, 1.1°C to 2.6°C under RCP4.5, 1.4°C to 3.1°C under RCP6.0 and 2.6°C to 4.8°C under RCP8.59 . The Arctic region will continue to warm more rapidly than the global mean (Figure SPM.6a, Figure SPM.7a). {2.2.1, Figure 2.1, Figure 2.2, Table 2.1} It is virtually certain that there will be more frequent hot and fewer cold temperature extremes over most land areas on daily and seasonal timescales, as global mean surface temperature increases. It is very likely that heat waves will occur with a higher frequency and longer duration. Occasional cold winter extremes will continue to occur. {2.2.1}" https://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full.pdf https://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FI...
cstross 8y ago
2 degrees over 200 years might be manageable. Alas, that's now at the very low end of what we're likely to see -- more probably, 2-4 degrees over 100 years. One problem with a single headline number is that this is an average temperature rise. What we're actually seeing is a mixture of things: more energy accumulating in the hydrosphere and atmosphere means more energetic weather events (e.g. powerful hurricanes/typhoons). Some areas warming lead to other areas cooling (e.g. melting Arctic ice cap and meltwater outflow from the Greenland ice cap may lead to temporary shutdown of the North Atlantic thermohaline circulation and a Gulf Stream stall, freezing the British Isles and Western Europe with a -5 to -10 celsius temperature drop in the short term -- meaning, decades to centuries). So there'll be a rise in the incidence of weather/climate related disasters. Another problem is that we can't simply shift agriculture to new, thawed territories. The Canadian Shield and Siberian Tundra are pretty poor soil, unsuited to intensive wheat/corn growing: it might be possible to condition them, but it'd take decades to centuries of hard work, during which other agricultural territory (the US mid-west and south, much of Asia and sub-Saharan Africa) will be subject to lethal heat emergencies. Lethal not so much for humans -- we know how to build solar-powered air conditioning -- but for crops and livestock which will die in the fields. Suggestions that we're one supermarket supply chain collapse away from the end of civilization are obviously bogus. But if we start having large-scale crop failures 3-5 times a decade, food prices will soar globally, leading eventually to civil unrest and war. (For example, the Arab Spring was to some extend a side-effect of the 2007-08 global financial crisis, as capital sought refuge in commodity futures and the price of bread throughout the Middle East doubled-to-tripled in twelve months: what will 2-4 consecutive wheat harvest failures accomplish?) Infrastructure damage (including agricultural infrastructure) due to strife and mass migration will in turn increase our dependence on surviving infrastructure, reducing our overall resilience. And there may eventually come a tipping point at which we end up in a positive-feedback loop of mutually reinforcing failures.
- tonylemesmer 8y ago
  yes - a single catastrophe could be weathered out in many cases, but once multiple events start happening it could quickly get quite unmanageable and then people will start changing behaviors permanently.
pjc50 8y ago
> Ecosystems and societies are pretty robust to that level of change over 200 years. Not so much the sea level, as the effect in change in average temperature; many plants have their reproduction cycles triggered by particular temperatures. The boundaries between different types of ecosystem are determined by temperature range. It will also make a difference to which crops are viable in which areas. It makes rather a lot more difference if you think of it not as "each day is 2C warmer than the corresponding day of the previous year" but instead "most days are the same temperature but some are warmer by enough to wipe out the local staple crop".
onion2k 8y ago
I think that we lose credibility when we speak of the end of civilisation. It won't take much of a change in the climate before we see significant conflict over access to water. India and Pakistan have a treaty they both signed in 1960 regarding access to water from 6 rivers they share (https://en.wikipedia.org/wiki/Indus_Waters_Treaty https://en.wikipedia.org/wiki/Indus_Waters_Treaty). These are two nations that have nuclear weapons... if that treaty fails and results in a war, that'd almost certainly end up being World War III, and could very well result in the end of civilisation. This isn't speculation on my part. We're already at the point where nations have civil wars over access to natural resources like water and agricultural land. It was a key factor in civil war in Sudan. Wars around the middle east between Israel and it's neighbours are rooted in religion but are often also about access to water from the Jordan basin. Climate change isn't simply things getting hotter and sea levels rising. People literally go to war over resources. It really matters.
- jessaustin 8y ago
  Humans have always gone to war, but recently that is less and less the case. Just like in USA, India and Pakistan's massive military spending is motivated more by corruption and self-dealing than by water shortages. They're not going to empty their nuclear stockpiles on each other. If they did, it would be a disaster, but it would still not amount to "the end of civilisation".
- roenxi 8y ago
  That is clearly very bad, but people also go to war because of scarce resources. The US doesn't have a Special Relationship with Saudi Arabia because the Saudi's are lovely people. Climate change isn't the threat, the problem is that population growth is exponential. We don't have a reliable mechanism to shrink population apart from run out of resources and have a war. Claiming that climate change is making resources scarce isn't grappling with the fact that in 100 years at 2% population growth, resources are going to be scarce anyway.
  - wohlergehen 8y ago
    While population development historically is exponential, looking at current societies all over the world indicate that there are ways to significantly reduce the growth: economic development, women's rights and education. In particular, population growth slows down where it matters, i.e. for those people that have the biggest carbon footprint.
jaggederest 8y ago
Well, if you would consider nuclear winter to be bad (and I certainly would), this is that, doubled, in reverse, plus lasting ten or more times as long. It's really difficult to overestimate the level of damage something like this would do to society. Picture half the population of humanity starving to death in famines or being killed in combat over water resources.
- jessaustin 8y ago
  I thought nuclear winter meant that photosynthesis would cease? That's obviously bad, but "doubled, in reverse" doesn't make sense in this context.
  - jaggederest 8y ago
    In terms of temperature change - nuclear winter is estimated to be a ~3C global reduction in temperature for ~10-20 years. And yes, you're right, photosynthesis would probably cease. We're going to see similar problems in the opposite direction, probably drought on a scale heretofore never experienced in human history in temperate areas. Imagine the climate of Los Angeles moving north to Vancouver BC, and similar cascading effects across the board.
zhdc1 8y ago
I'm familiar with some of the research on government policy acceptance/salience viz-a-viz climate change and alternative energy (I have a PhD interview tomorrow on this very subject), and I agree with some of what you're saying. Western society is robust, and over a long time period many of the more dire impacts from rising temperatures will be mitigated in one way or another. The issue is that, while climate change at UN COP21-23 estimates isn't necessarily an existential threat to Western society, it 1.) has exceptionally real effects on individuals who are affected (and those who are going to be affected in the near future) and 2.) requires an enormous amount of investment and development to manage the transition from a pre 2C rise to a post 2C rise. When you're looking at having to protect at least 20K+ square km of land and ~150-200M people, some amount of directness is acceptable.
- PeterisP 8y ago
  Saying "we are all doomed" is not some amount of directness. Saying "200mm of people will migrate or die" (assuming its true) would be direct, but the "we are all doomed" is very misleading because the effects are not universal and not evenly distributed. The described scenarios will not cause doom to me, and most likely to you as well. Furthermore, even for the politicians that have completely publicly accepted the notion of climate change, statements like "requires an enormous amount of investment and development to manage the transition" and "having to protect at least 20K+ square km of land and ~150-200M people" are simply literally false - they can (and possibly will) choose not to protect that land and those people, because they're "others". They have the ability to choose not investing in managing that transition globally, but only handling the direct local consequences, and protect their population from the global effects simply by investing into armaments/defence industry - as Dr. Hillman is saying in the original article, "How are these regions going to respond? We see it now. Migrants will be prevented from arriving. We will let them drown." Looking at some of our global leaders, such a scenario seems at least possible.
seer 8y ago
Its hard to overstate how big of a change just 2 degrees can actually make. I remember that xkcd did several really nice graphs showing the scope of it all, in eli5 language https://xkcd.com/1379/ https://xkcd.com/1379/ https://xkcd.com/1732/ https://xkcd.com/1732/ https://xkcd.com/1321/ https://xkcd.com/1321/ I can’t in good conscience call them fun, “terrifying” would be a bit more accurate
dzdt 8y ago
I agree. The climate science is overwhelming: temperature rise, sea level rise, and other related changes are happening on large eco-system-changing scales. There is no stopping it and even drastic action will only slightly slow the changes within a 100 year timeframe. For a rich country like the United States, the climate change itself is survivable. So Arizona becomes unsurvivable desert and Lousiana is lost to the sea; New York builds seawalls and subway pumps and Miami partly becomes Venice and partly Atlantis. The Great Sandhill Desert re-emerges from the plains. Food prices increase; diets shift to accomodate -- less beef; more chicken; more vegetarianism. Diseases associated to warmer places spread: malaria and zika. Millions of people are forced to move. But civilisation itself isn't really threatened. The civilisation-threatening problems happen in poorer countries. Population size, though growth has been slowing for decades, will not have peaked before climate change reduces carrying capacities. Waves of refugees from the resulting famines and wars will try to make their way inland and northward. What will happen when India and Pakistan, nuclear powers both, are overwhelmed by mass displacement and food shortages? How many refugees will we accept, and how many will we turn our backs on? What will our role be in the wars?
- nickik 8y ago
  Why would food prices increase. Framing is limited by the cold, so warming will open up more land. Not to mention that higher carbon has been shown to improve yields. I think food shortages are highly unlikely specially when you have global markets.
  - dzdt 8y ago
    More farmland is lost to desert than gained to warmth. Pastureland in particular is affected, making cattle more expensive to raise. Also farming is energy-intensive and a rise in costs of fuel will pass on to food prices.
    - nickik 8y ago
      The total farmland use hasn't gone up a lot anyway. We have lots and lots of land that could be farmed if we needed it to. Its absolutely not the issue. Secondly, what evidence do you have that fuel will be more expensive? The shale revolution has made gas cheap and it will stay so for a long time. You can make methanol with gas for example. The proven reserves go up of fossil fuels as well. There is also no limit on electrical energy, we could build nuclear plants until the cows come home if that is required. France has shown that it possible and that it is not unreasonably expensive. Even if farmland would somehow be an issue, we could easily do factory farming. The only reason we don't is that its more expensive then using land.
dredmorbius 8y ago
Past human civilisations have fared poorly under even modest climate change. There's a strong argument that technological civilisation dependent on vast nonrenewable resource utilisation is not favourably positioned by comparison. Large animal populations (> ~10kg) have responded poorly to larger ones, of the scale we're facing in < 100 years. Good earlier discussion, and links: https://plus.google.com/+YonatanZunger/posts/SgzQU5DM3LQ https://plus.google.com/+YonatanZunger/posts/SgzQU5DM3LQ
f_allwein 8y ago
"Say goodbye to the Eastern Seaboard of the U.S., to Mexico and Central America, to the middle third of South America. In Africa, Mozambique and Madagascar are gone; Asia loses much of the Indian subcontinent, including all of Pakistan; Indochina is abandoned, as is most of Indonesia." This is from a scenario where the world warms by 4 degrees. Other parts of the world, e.g. Western Australia and Canada, would benefit. See http://bigthink.com/strange-maps/what-the-world-will-look-like-4degc-warmer http://bigthink.com/strange-maps/what-the-world-will-look-li...
mamcx 8y ago
9/11 was "just" 2 big buildings (plus a few smaller ones) collapsing. Katrina was "just" a local event. And see how civilization respond to this. Now, think what will happend if we get this kind of events more often, EVERYWHERE. AT THE SAME-ish TIME.
- passiveincomelg 8y ago
  I think we will become numb to it like we became numb to war, hunger and all the other atrocities happening in many places at the same-ish time.

by ppod 8y ago

arnoooooo 8y ago

It's much more than a 2C rise and that will happer much faster than 2200. Even 2C is half an ice-age in magnitude, and it would be happening much faster. You can read my attempt at a primer, which details some of the consequences here : https://climate.btmx.fr https://climate.btmx.fr

ThomPete 8y ago
2C is the popularized number. In reality it's a range (0.8-2.6 for 2050 and 1.4-1.4-5.8 for 2100) and it's not certain how much humans can do about it or have to do with it (we are probably affecting it but how much is still an open question) We have been figthing to survive nature from the start. Ex. sea rise is not a problem that can't be solved just look at Holland. http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29 http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29
- lozenge 8y ago
  > it's not certain how much humans can do about it or have to do with it (we are probably affecting it but how much is still an open question) What is your point in saying this? Everything always has uncertainties, but scientists and economists are in agreement there is enough known that we need large changes in energy use (which affects all sectors of the economy). That is found in the latest version of the report you linked to, or even the version you linked. The idea that Bangladesh can "solve" sea level rise because Holland can is laughable. Just look at these maps: http://www.realclimate.org/index.php/archives/2015/08/bjorn-lomborg-just-a-scientist-with-a-different-opinion/ http://www.realclimate.org/index.php/archives/2015/08/bjorn-...
  - ThomPete 8y ago
    Not sure there is any reason to debate someone who deliberately oversimplify what I say, call it laughable and then point to a highly biased website. Of course Holland and Bangladesh isn't the same situation so to call your own strawman laughable says a lot about where you are coming from in this. But against my better judgement I am still engaging in the hopes that you are in fact interested in hearing what my point is. Yes everything has uncertainties which would be good to remember in this debate as thats the difference between whether we are doomed or whether the climate will change as I has always done and we need to adjust to it. Instead of trying to claim that we know for a fact what the outcome is, how big our involvement in climate change is, how much we can do something about. Even the IPCC does not deal in such certainties and have toned down their doomsdaying over the years. That's important to keep in mind before we all jump on the "we are doomed" bandwagon. There are things we can do especially these days as we are much better at handling nature than we were 100 years ago which means that no matter how much of climate change is manmade we have a better chance of dealing with the consequences today than if those changes had happened 100 years ago.
akvadrako 8y ago
We don't know historical global temperatures well enough to say if anthropogenic warming is particularly fast. For example the Younger Dryas¹, about 15ky ago. The best estimate is global temp dropped 2-6° over 50 years and 1000 years later, did the opposite. Before that our data is so poor it's hard to distinguish between 1000 years and 1 year. [1] https://www.ncdc.noaa.gov/abrupt-climate-change/The%20Younger%20Dryas https://www.ncdc.noaa.gov/abrupt-climate-change/The%20Younge...

SwellJoe 8y ago

Conservative estimates put it at 2.8 degrees by 2100. Do you believe the temperature will stop rising in 2100? By what mechanism will it stop rising?

ThomPete 8y ago
Conservative put it at 1.4 http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29 http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=29
- SwellJoe 8y ago
  OK, will it stop at 1.4? If so, how?
  - deleted 8y ago
    [deleted]
- lozenge 8y ago
  That's including the "radical action taken now" scenario (RCP), which anybody can see is not happening. It is also from AR3, the latest report is AR5, published over a decade later.
  - ThomPete 8y ago
    Here is the AR5 report which is toning down it's previous predictions from in other words things weren't as bad as claimed. It's not as black and white and the consequences are even more speculative. "Future climate will depend on committed warming caused by past anthropogenic emissions, as well as future anthropogenic emissions and natural climate variability. The global mean surface temperature change for the period 2016–2035 relative to 1986–2005 is similar for the four RCPs and will likely be in the range 0.3°C to 0.7°C (medium confidence). This assumes that there will be no major volcanic eruptions or changes in some natural sources (e.g., CH4 and N2O), or unexpected changes in total solar irradiance. By mid-21st century, the magnitude of the projected climate change is substantially affected by the choice of emissions scenario. {2.2.1, Table 2.1} Relative to 1850–1900, global surface temperature change for the end of the 21st century (2081–2100) is projected to likely exceed 1.5°C for RCP4.5, RCP6.0 and RCP8.5 (high confidence). Warming is likely to exceed 2°C for RCP6.0 and RCP8.5 (high confidence), more likely than not to exceed 2°C for RCP4.5 (medium confidence), but unlikely to exceed 2°C for RCP2.6 (medium confidence). {2.2.1} The increase of global mean surface temperature by the end of the 21st century (2081–2100) relative to 1986–2005 is likely to be 0.3°C to 1.7°C under RCP2.6, 1.1°C to 2.6°C under RCP4.5, 1.4°C to 3.1°C under RCP6.0 and 2.6°C to 4.8°C under RCP8.59 . The Arctic region will continue to warm more rapidly than the global mean (Figure SPM.6a, Figure SPM.7a). {2.2.1, Figure 2.1, Figure 2.2, Table 2.1} It is virtually certain that there will be more frequent hot and fewer cold temperature extremes over most land areas on daily and seasonal timescales, as global mean surface temperature increases. It is very likely that heat waves will occur with a higher frequency and longer duration. Occasional cold winter extremes will continue to occur. {2.2.1}" https://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full.pdf https://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FI...

cstross 8y ago

2 degrees over 200 years might be manageable. Alas, that's now at the very low end of what we're likely to see -- more probably, 2-4 degrees over 100 years. One problem with a single headline number is that this is an average temperature rise. What we're actually seeing is a mixture of things: more energy accumulating in the hydrosphere and atmosphere means more energetic weather events (e.g. powerful hurricanes/typhoons). Some areas warming lead to other areas cooling (e.g. melting Arctic ice cap and meltwater outflow from the Greenland ice cap may lead to temporary shutdown of the North Atlantic thermohaline circulation and a Gulf Stream stall, freezing the British Isles and Western Europe with a -5 to -10 celsius temperature drop in the short term -- meaning, decades to centuries). So there'll be a rise in the incidence of weather/climate related disasters. Another problem is that we can't simply shift agriculture to new, thawed territories. The Canadian Shield and Siberian Tundra are pretty poor soil, unsuited to intensive wheat/corn growing: it might be possible to condition them, but it'd take decades to centuries of hard work, during which other agricultural territory (the US mid-west and south, much of Asia and sub-Saharan Africa) will be subject to lethal heat emergencies. Lethal not so much for humans -- we know how to build solar-powered air conditioning -- but for crops and livestock which will die in the fields. Suggestions that we're one supermarket supply chain collapse away from the end of civilization are obviously bogus. But if we start having large-scale crop failures 3-5 times a decade, food prices will soar globally, leading eventually to civil unrest and war. (For example, the Arab Spring was to some extend a side-effect of the 2007-08 global financial crisis, as capital sought refuge in commodity futures and the price of bread throughout the Middle East doubled-to-tripled in twelve months: what will 2-4 consecutive wheat harvest failures accomplish?) Infrastructure damage (including agricultural infrastructure) due to strife and mass migration will in turn increase our dependence on surviving infrastructure, reducing our overall resilience. And there may eventually come a tipping point at which we end up in a positive-feedback loop of mutually reinforcing failures.

tonylemesmer 8y ago
yes - a single catastrophe could be weathered out in many cases, but once multiple events start happening it could quickly get quite unmanageable and then people will start changing behaviors permanently.

pjc50 8y ago

> Ecosystems and societies are pretty robust to that level of change over 200 years. Not so much the sea level, as the effect in change in average temperature; many plants have their reproduction cycles triggered by particular temperatures. The boundaries between different types of ecosystem are determined by temperature range. It will also make a difference to which crops are viable in which areas. It makes rather a lot more difference if you think of it not as "each day is 2C warmer than the corresponding day of the previous year" but instead "most days are the same temperature but some are warmer by enough to wipe out the local staple crop".

onion2k 8y ago

I think that we lose credibility when we speak of the end of civilisation. It won't take much of a change in the climate before we see significant conflict over access to water. India and Pakistan have a treaty they both signed in 1960 regarding access to water from 6 rivers they share (https://en.wikipedia.org/wiki/Indus_Waters_Treaty https://en.wikipedia.org/wiki/Indus_Waters_Treaty). These are two nations that have nuclear weapons... if that treaty fails and results in a war, that'd almost certainly end up being World War III, and could very well result in the end of civilisation. This isn't speculation on my part. We're already at the point where nations have civil wars over access to natural resources like water and agricultural land. It was a key factor in civil war in Sudan. Wars around the middle east between Israel and it's neighbours are rooted in religion but are often also about access to water from the Jordan basin. Climate change isn't simply things getting hotter and sea levels rising. People literally go to war over resources. It really matters.

jessaustin 8y ago
Humans have always gone to war, but recently that is less and less the case. Just like in USA, India and Pakistan's massive military spending is motivated more by corruption and self-dealing than by water shortages. They're not going to empty their nuclear stockpiles on each other. If they did, it would be a disaster, but it would still not amount to "the end of civilisation".
roenxi 8y ago
That is clearly very bad, but people also go to war because of scarce resources. The US doesn't have a Special Relationship with Saudi Arabia because the Saudi's are lovely people. Climate change isn't the threat, the problem is that population growth is exponential. We don't have a reliable mechanism to shrink population apart from run out of resources and have a war. Claiming that climate change is making resources scarce isn't grappling with the fact that in 100 years at 2% population growth, resources are going to be scarce anyway.
- wohlergehen 8y ago
  While population development historically is exponential, looking at current societies all over the world indicate that there are ways to significantly reduce the growth: economic development, women's rights and education. In particular, population growth slows down where it matters, i.e. for those people that have the biggest carbon footprint.

jaggederest 8y ago

Well, if you would consider nuclear winter to be bad (and I certainly would), this is that, doubled, in reverse, plus lasting ten or more times as long. It's really difficult to overestimate the level of damage something like this would do to society. Picture half the population of humanity starving to death in famines or being killed in combat over water resources.

jessaustin 8y ago
I thought nuclear winter meant that photosynthesis would cease? That's obviously bad, but "doubled, in reverse" doesn't make sense in this context.
- jaggederest 8y ago
  In terms of temperature change - nuclear winter is estimated to be a ~3C global reduction in temperature for ~10-20 years. And yes, you're right, photosynthesis would probably cease. We're going to see similar problems in the opposite direction, probably drought on a scale heretofore never experienced in human history in temperate areas. Imagine the climate of Los Angeles moving north to Vancouver BC, and similar cascading effects across the board.

zhdc1 8y ago

I'm familiar with some of the research on government policy acceptance/salience viz-a-viz climate change and alternative energy (I have a PhD interview tomorrow on this very subject), and I agree with some of what you're saying. Western society is robust, and over a long time period many of the more dire impacts from rising temperatures will be mitigated in one way or another. The issue is that, while climate change at UN COP21-23 estimates isn't necessarily an existential threat to Western society, it 1.) has exceptionally real effects on individuals who are affected (and those who are going to be affected in the near future) and 2.) requires an enormous amount of investment and development to manage the transition from a pre 2C rise to a post 2C rise. When you're looking at having to protect at least 20K+ square km of land and ~150-200M people, some amount of directness is acceptable.

PeterisP 8y ago
Saying "we are all doomed" is not some amount of directness. Saying "200mm of people will migrate or die" (assuming its true) would be direct, but the "we are all doomed" is very misleading because the effects are not universal and not evenly distributed. The described scenarios will not cause doom to me, and most likely to you as well. Furthermore, even for the politicians that have completely publicly accepted the notion of climate change, statements like "requires an enormous amount of investment and development to manage the transition" and "having to protect at least 20K+ square km of land and ~150-200M people" are simply literally false - they can (and possibly will) choose not to protect that land and those people, because they're "others". They have the ability to choose not investing in managing that transition globally, but only handling the direct local consequences, and protect their population from the global effects simply by investing into armaments/defence industry - as Dr. Hillman is saying in the original article, "How are these regions going to respond? We see it now. Migrants will be prevented from arriving. We will let them drown." Looking at some of our global leaders, such a scenario seems at least possible.

seer 8y ago

Its hard to overstate how big of a change just 2 degrees can actually make. I remember that xkcd did several really nice graphs showing the scope of it all, in eli5 language https://xkcd.com/1379/ https://xkcd.com/1379/ https://xkcd.com/1732/ https://xkcd.com/1732/ https://xkcd.com/1321/ https://xkcd.com/1321/ I can’t in good conscience call them fun, “terrifying” would be a bit more accurate

dzdt 8y ago

I agree. The climate science is overwhelming: temperature rise, sea level rise, and other related changes are happening on large eco-system-changing scales. There is no stopping it and even drastic action will only slightly slow the changes within a 100 year timeframe. For a rich country like the United States, the climate change itself is survivable. So Arizona becomes unsurvivable desert and Lousiana is lost to the sea; New York builds seawalls and subway pumps and Miami partly becomes Venice and partly Atlantis. The Great Sandhill Desert re-emerges from the plains. Food prices increase; diets shift to accomodate -- less beef; more chicken; more vegetarianism. Diseases associated to warmer places spread: malaria and zika. Millions of people are forced to move. But civilisation itself isn't really threatened. The civilisation-threatening problems happen in poorer countries. Population size, though growth has been slowing for decades, will not have peaked before climate change reduces carrying capacities. Waves of refugees from the resulting famines and wars will try to make their way inland and northward. What will happen when India and Pakistan, nuclear powers both, are overwhelmed by mass displacement and food shortages? How many refugees will we accept, and how many will we turn our backs on? What will our role be in the wars?

nickik 8y ago
Why would food prices increase. Framing is limited by the cold, so warming will open up more land. Not to mention that higher carbon has been shown to improve yields. I think food shortages are highly unlikely specially when you have global markets.
- dzdt 8y ago
  More farmland is lost to desert than gained to warmth. Pastureland in particular is affected, making cattle more expensive to raise. Also farming is energy-intensive and a rise in costs of fuel will pass on to food prices.
  - nickik 8y ago
    The total farmland use hasn't gone up a lot anyway. We have lots and lots of land that could be farmed if we needed it to. Its absolutely not the issue. Secondly, what evidence do you have that fuel will be more expensive? The shale revolution has made gas cheap and it will stay so for a long time. You can make methanol with gas for example. The proven reserves go up of fossil fuels as well. There is also no limit on electrical energy, we could build nuclear plants until the cows come home if that is required. France has shown that it possible and that it is not unreasonably expensive. Even if farmland would somehow be an issue, we could easily do factory farming. The only reason we don't is that its more expensive then using land.

dredmorbius 8y ago

Past human civilisations have fared poorly under even modest climate change. There's a strong argument that technological civilisation dependent on vast nonrenewable resource utilisation is not favourably positioned by comparison. Large animal populations (> ~10kg) have responded poorly to larger ones, of the scale we're facing in < 100 years. Good earlier discussion, and links: https://plus.google.com/+YonatanZunger/posts/SgzQU5DM3LQ https://plus.google.com/+YonatanZunger/posts/SgzQU5DM3LQ

f_allwein 8y ago

"Say goodbye to the Eastern Seaboard of the U.S., to Mexico and Central America, to the middle third of South America. In Africa, Mozambique and Madagascar are gone; Asia loses much of the Indian subcontinent, including all of Pakistan; Indochina is abandoned, as is most of Indonesia." This is from a scenario where the world warms by 4 degrees. Other parts of the world, e.g. Western Australia and Canada, would benefit. See http://bigthink.com/strange-maps/what-the-world-will-look-like-4degc-warmer http://bigthink.com/strange-maps/what-the-world-will-look-li...

mamcx 8y ago

9/11 was "just" 2 big buildings (plus a few smaller ones) collapsing. Katrina was "just" a local event. And see how civilization respond to this. Now, think what will happend if we get this kind of events more often, EVERYWHERE. AT THE SAME-ish TIME.

passiveincomelg 8y ago
I think we will become numb to it like we became numb to war, hunger and all the other atrocities happening in many places at the same-ish time.