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Climate Science Is Not Settled

61 points by T-A 12y ago

scarmig 12y ago
"The crucial scientific question for policy isn't whether the climate is changing. That is a settled matter: The climate has always changed and always will. Geological and historical records show the occurrence of major climate shifts, sometimes over only a few decades. We know, for instance, that during the 20th century the Earth's global average surface temperature rose 1.4 degrees Fahrenheit. Nor is the crucial question whether humans are influencing the climate. That is no hoax: There is little doubt in the scientific community that continually growing amounts of greenhouse gases in the atmosphere, due largely to carbon-dioxide emissions from the conventional use of fossil fuels, are influencing the climate. There is also little doubt that the carbon dioxide will persist in the atmosphere for several centuries. The impact today of human activity appears to be comparable to the intrinsic, natural variability of the climate system itself... Society's choices in the years ahead will necessarily be based on uncertain knowledge of future climates. That uncertainty need not be an excuse for inaction." Much better than I expected of the WSJ. If it consistently took this line instead of buying into absurd conspiracy theories or claiming snow in January means climate change is a hoax, our national discourse would be much healthier, on both sides.
hristov 12y ago
FUD is not only for operating systems anymore.
quink 12y ago
> Dr. Koonin was undersecretary for science in the Energy Department during President Barack Obama's first term and is currently director of the Center for Urban Science and Progress at New York University. His previous positions include professor of theoretical physics and provost at Caltech, as well as chief scientist of BP, BP.LN +0.42% where his work focused on renewable and low-carbon energy technologies. > We are very far from the knowledge needed to make good climate policy Complete and total horseshit. Even if you'd only assume that the scientists are 90% right any good actuaries will tell you that you should spend about 90% on measures that back up what they've put forward. Hacker News, I expected something better than this in the #2 spot. Here, read this: http://www.ipcc.ch/report/ar5/ http://www.ipcc.ch/report/ar5/ Or this: http://en.wikipedia.org/wiki/Global_warming http://en.wikipedia.org/wiki/Global_warming Or this: http://en.wikipedia.org/wiki/Ocean_acidification http://en.wikipedia.org/wiki/Ocean_acidification Or this one is excellent: http://www.skepticalscience.com/ http://www.skepticalscience.com/ Edit: Alright, here we go with the downvotes for calling out bullshit regarding climate change on Hacker News. Well, it's not like I expected any better. Next I expect a replies either trying to argue random points about how there were forests in Greenland in the middle ages or some pretensions about being open-minded. While still barely having a grasp of a periphery of relevant facts. But that's OK, the warriors having upvoted this to the top immediately know best. Or at least as well as Murdoch, publisher of the WSJ who has recently installed a prime minister in Australia who called climate change 'crap' and has abolished a carbon tax a minute fraction of those found in the rest of the OECD.
- triangleman 12y ago
  What's your point? That Dr. Koonin is not a trustworthy source because he worked for BP?
  - lotsofmangos 12y ago
    I would take the opinions of an industry expert with a large pinch of salt on the subject of negative externalities of the industry they are involved in, no matter what the industry.
  - Daishiman 12y ago
    Yes?
- igravious 12y ago
  Whatever. I am sick to the back teeth of "the sky is falling!" rhetoric. I refuse to live in mortal fear for the future of humanity. The climate will change, big deal, we'll adapt -- the range of habitats humans inhabit far exceeds the variation in climate that individual habitats will experience. On the list of things to worry about climate change should be way down. But wow, you're so vocal -- because you feel that it is an existential threat. Newsflash, it ain't. Homelessness is a bigger problem. Ditto poverty and starvation. I _welcome_ the push back against the drumbeats and rhetoric and hope climate change disappears off the political agenda entirely. Some hope.
  - Squarel 12y ago
    You don't think homelessness/starvation/food security/water security will be affected by any future changes in climate?
  - quink 12y ago
    It is a bit of an existentialist threat. It's one of the possible answers to the Fermi paradox. Why haven't we met anyone? Because they boiled themselves to bits before they could interstellar space. Which, inherently, requires huge amounts of energy, possibly enough to change climates. I can't think of things more fundamental to existence or non-existence in this universe than it being the wrong temperature.
tlb 12y ago
I'm surprised by the finest possible resolution quoted, a 60 mile grid. It corresponds to about 55,000 cells covering earth (times maybe 100 altitude bands). That's not a large amount of memory. I assume the limitation is that all those cells have to be simulated in small time slices for 100 years, and the necessary time slice would scale inversely with the grid size, so computation is O(n^3) on the inverse size of the grid. Can someone comment on what kind of computer it would take to halve the size of the grid?
- tjradcliffe 12y ago
  There are usually quite a bit fewer than 100 altitude slices. There may be as few as 10: http://www.ipcc-data.org/guidelines/pages/gcm_guide.html http://www.ipcc-data.org/guidelines/pages/gcm_guide.html Simulations are typically done in one day time-steps or less. The thing is, there is a lot of physics going on in each cell, and in some respects reducing the cell size makes things more problematic rather than less. For example, the effects of a supercell thunderstorm can dominate the atmosphere over tens of kilometers. With a 100 km (60 mile) scale you can plausibly average over those effects within a cell, as you can reasonably claim that most such "local" phenomena will be happening well away from cell boundaries. So as you reduce the cell size, you start having to think about the internal details of local disturbances that you were previously averaging away and hoping to catch in your overall parameterizations, and the model complexity goes up tremendously, likely without becoming a whole lot more accurate. Even at these large scales the amount of physics that goes on within a single cell is huge, and getting all the heat and mass balances right is fantastically difficult, which is where a lot of the computational power goes. So it isn't really a question of halving the grid size while keeping the physics the same, because you are going to have to substantially revise your model to accommodate the new scale. I'm sure this work is ongoing, but it's extremely complex and difficult.
  - rwallace 12y ago
    What sort of physics calculations can you do within a cell? I would have expected the data structure for a cell to contain a handful of scalar parameters (e.g. temperature, pressure, humidity, velocity vector) related by a few scalar equations - a negligible amount of computation. It sounds like there's quite a few orders of magnitude more stuff going on within a cell than I would have expected. What am I missing?
tjradcliffe 12y ago
Steve Koonin is an incredibly smart guy with a huge amount of experience in climate and energy issues, and is saying things in this article that any competent computational physicist who has looked into climate modelling believes. Compare for example my own short take on the same issues, written two years ago: http://www.tjradcliffe.com/?p=886 http://www.tjradcliffe.com/?p=886 You'll see basically similar concerns raised. If you're seriously wedded to the idea that consensus is important to the science, you should dig up the independent opinions of a few other computational physicists (not climate scientists, who are not computational physicists). Having done so, you might find that there is a consensus amongst computational physicists that climate models are problematic in ways that make them questionable guides to policy, although most of us will also say that we should be concerned about the amount of garbage we are dumping into the atmosphere (and there are reasons to want to get off fossil fuels that go beyond the climate change argument.) Denialists have poisoned the public discourse on climate change, but Warmists have unfortunately responded by digging in their heels in a particularly anti-scientific way. I hope Koonin's piece will help bring the scientific discussion back to fundamentals, and perhaps decouple the policy discussion from models a bit. For example: we know that carbon taxes work pretty well in reducing CO2 emissions (http://www.theglobeandmail.com/globe-debate/the-insidious-truth-about-bcs-carbon-tax-it-works/article19512237/ http://www.theglobeandmail.com/globe-debate/the-insidious-tr...) and we know that carbon taxes can be used to reduce corporate and income taxes. So anyone who is opposed to carbon taxes is necessarily in favour of higher corporate and income taxes. This is a policy discussion that can and should be had independently of any detailed climate model results, and I invite everyone who is in favour of higher corporate and income taxes to chime in here in support of their position, and explain why those taxes are so much better than the carbon taxes that could partially replace them.
- quink 12y ago
  http://www.skepticalscience.com/climate-models-intermediate.htm http://www.skepticalscience.com/climate-models-intermediate.... http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/jul/21/realistic-climate-models-accurately-predicted-global-warming http://www.theguardian.com/environment/climate-consensus-97-... And can you please stop with the 'Warmist' label? It's stupid, about as much as 'denialist' is narrow for the veritable zoo of opinions - educated or uneducated - that's sprung up in the public discourse. I've also read your post and 1-2 W/m2 does sound like very little. However, and I quote from Wikipedia: > Of the ~340 W/m2 of solar radiation received by the Earth, an average of ~77 W/m2 is reflected back to space by clouds and the atmosphere, and ~23 W/m2 is reflected by the surface albedo, leaving about 240 W/m2 of solar energy input to the Earth's energy budget. That's a change of 0.5%. Doesn't sound like much, does it, but at 273 K that corresponds to about 1.5 degrees already. At the upper end of that and 300 K it's 2.5 degrees. Sure, it's simplistic and it's how to keep it quite that straightforward, but to see that number and be ignorant enough of the context to trivialise it and call it not a big deal is pretty disingenuous. Sure, a 2.5 K (or something like it) rise isn't going to bring the downfall of civilisation per se. But there's more to it than that. And, mind you, 2.5 K is at the lower end of IPCC projections, so there's evidently a lot more ground to cover than the simplistic numbers mentioned here.
j2kun 12y ago
"Settled" is not a word you can use when describing any science. Medicine is not settled, nor is physics or computer science. But we can still glean useful insights from the evidence and experiments we have done. While it's wrong to claim climate science is settled, I can't recall any credible figure who said that it was. So to me this seems like a bit of a straw man.
qthrul 12y ago
Science is that which explains and predicts. If you are missing either of these attributes -- you are in the realm of legends, folklore, and farmer's almanacs.
haberman 12y ago
"Climate Science Is Not Settled" is an irresponsible title IMO when the main points of contention in public discourse are whether anthropogenic climate change is even real or not, and action vs. inaction. It's a good article and I'm happy to see it (assuming the information is accurate). But deniers will point to the title to argue that the whole things is a hoax and that we should do nothing. I'm sure the phenomenon of "Warmists" is a real thing too, and something to watch out for. But it's incredibly hard to talk about the subtle points presented in this article when so many people refuse to believe that anything is happening at all. It's like trying to debate foreign policy with someone who thinks that 9/11 was an inside job.
lutorm 12y ago
I always thought that when people used the word "settled" in connection to climate change they were referring to the question of whether humans have influenced climate. Even though this article dismisses that question as "yeah there's little doubt about that", this is precisely what plenty of people have been arguing is not the case. So this article seems a lot like moving the goal posts to me. Obviously climate science as a whole isn't "settled", any more than any other science is "settled".
- hencq 12y ago
  Yeah I agree. The article was actually good and calls out very reasonable criticisms against current climate science. However the headline makes it seem the debate on whether humans influence the climate isn't settled.
  - lotsofmangos 12y ago
    That is most likely intentional. The headline was probably come up with from on high before any experts were even solicited to write the piece.
  - ende 12y ago
    One thing that the author points out is that the impact by humans is relatively small (compared to natural sourcing), and that natural variation is both vast and frequent.
e40 12y ago
I was hoping to find something about acidification of sea water, caused by CO2. Even if the warmth of the earth isn't caused by us, it seems like the acidification of the ocean might be. A similarly skeptical look at this would be welcomed.
- ende 12y ago
  Please, this debate is contentious enough without bringing SQL-vs-NoSQL into it.
Daishiman 12y ago
Wow. I am amazed that an article filled with such a vast amount of FUD is frontpaging. But let's go point-by-point, lest the science described in thousands of papers of climate research get lost in the cloud of false skepticism, shall we? > The models roughly describe the shrinking extent of Arctic sea ice observed over the past two decades, but they fail to describe the comparable growth of Antarctic sea ice, which is now at a record high. The science of why Antarctic sea ice extent is growing is perfectly well known: the discharge of melting cold water from the Antarctic glaciers forms ice as it hits the coastal winds of the continent. That the models don't necessarily account the extent of this is almost irrelevant, since the sea ice extent has a very minute impact on climate patterns. Let us note that this is a not-at-all subtle piece of FUD that would appear to account that Antarctic sea ice is compensating for Arctic melting. It's not. There's over 500 Gt of yearly glacier loss in the Antarctic, and the sea ice extent which is, at most, a few meters thick, is absolutely minuscule in comparison to the amount of additional water dissolving into the sea from kilometers-thick walls of ice. Also, the topic has been reasonably well-studied, and the changes in the atmosphere are more than enough to account for the observed effects. > Even though the human influence on climate was much smaller in the past, the models do not account for the fact that the rate of global sea-level rise 70 years ago was as large as what we observe today—about one foot per century. It is most definitely increasing, and it is accelerating rapidly, especially if the West Antarctic Ice Sheet accelerates its collapse (http://www.skepticalscience.com/sea-level-rise.htm http://www.skepticalscience.com/sea-level-rise.htm). The fact that we have been observing linear trends thus far doesn't mean that we'll continue to observe them; evidence points that we're in the beggining of an exponential loss of ice. > A crucial measure of our knowledge of feedbacks is climate sensitivity—that is, the warming induced by a hypothetical doubling of carbon-dioxide concentration. Today's best estimate of the sensitivity (between 2.7 degrees Fahrenheit and 8.1 degrees Fahrenheit) is no different, and no more certain, than it was 30 years ago. And this is despite an heroic research effort costing billions of dollars. This is, again, FUD. First of all, the radiative forcing produced by CO2 is well-known and established by physics. It is known that the Earth's albedo is decreasing, and the certainty that out lower bounds are erroneous has increased substantially. Moreover, we are now aware of potential feedback loops that we didn't know about. It's interesting that he's never mentioning the Big One: the potential for frozen clathrates in Siberia and the Arctic to release methane that would trigger a certain mass extinction event. > A transparent rigor would also be a welcome development, especially given the momentous political and policy decisions at stake. That could be supported by regular, independent, "red team" reviews to stress-test and challenge the projections by focusing on their deficiencies and uncertainties; that would certainly be the best practice of the scientific method. But because the natural climate changes over decades, it will take many years to get the data needed to confidently isolate and quantify the effects of human influences. So, in his opinion, the models clearly described in papers, the data publicly available by NASA and dozens of different government organizations is not enough? A 3000-page report summarizing the findings of hundreds of papers, with multiple, independently corroborated lines of evidence using different data sets isn't enough? This an obvious attempt to discredit climate scientists. I would suggest anyone who has a shred of doubt as to the integrity of these people that you just walk into any Atmospheric Sciences Department of your local university and buy any teacher a cup of coffee and have a chat. Seriously, they will talk your ear off about their research. As a personal note, most climate scientists are the kind of people smart enough and capable enough to be making decent cunks of money outside of their chosen field (a combination of knowledge in physics, chemistry, and computational modeling are desired skill in many lucrative fields). They're not doing this for the money, or the recognition, and it pains me that people are willing to believe the ramblings posted in a Murdoch-owned newspaper on the matter without willing to question the economic interests behind climate denialism. But I digress. > But climate strategies beyond such "no regrets" efforts carry costs, risks and questions of effectiveness, so nonscientific factors inevitably enter the decision. These include our tolerance for risk and the priorities that we assign to economic development, poverty reduction, environmental quality, and intergenerational and geographical equity. There's something that should be really important, which people raised on the typical media diet of "two sides of the story" and "fair and balanced" should understand: We're not debating whether climate change is something serious or not. The current debate is whether we're facing a future where "merely" the following things will happen: * An acidified ocean where almost all fish stocks will collapse, with a PH that will make the growth of crustaceans and zooplankton difficult, to say the least. * Megadroughts will become a common occurency, as will increased levels of flooding resulting in losses of crop efficiencies above 10% * All of the planet's ecosystems will be permanently affected, making the harvesting of crops such as coffee and cocoa a thing of the past * An acceleration into our current period of mass extinction, with unforeseen consequences Or, nn the other extreme, quite literally, we have a scenario of a degradation of the Earth's biosphere to the point where humans face complete extinction within the next century. The last scenario could be triggered by one of the many feedback cycles which include the sudden release of methane clathrates, an exponential collapse of the West Antarctic Ice Sheet leading to the rapid increase in sea level of multiple feet, or just sufficiently large megadrought events in enough places in the globe to disrupt the global food supply chain. Hell, just an increase in temperature of 4 degrees C ("just") would be enough. My final rebuttal: > Individuals and countries can legitimately disagree about these matters No, they cannot, unless they're legitimate experts in climate science with an understanding that actually improves upon what we have, they have squat to say on the science of it. This fake notion that anyone can have an opinion on knowledge that's in flux is intellectually dishonest. Experts are allowed to disagree. Us laymen have almost nothing to add to the conversation, unless we want to gamble with our own demise. Anyone who thinks otherwise is plainly ignorant of the science, and that's not a point in discussion. The only thing this discourse does is play down the supposed "alarmism" of the situation. I don't know man, if you think that a potential, non-trivial chance of the collapse of the biosphere isn't something to be alarmed of, then I don't know what is.
grifpete 12y ago
It seems that the article has a simple thesis. a) climate is hard b) human activity is affecting it but because it's hard it's tough to know how much c) hence it's difficult to know what the correct policies should be. As an economist might say - without clarity on the positive, it's challenging to resolve the normative. But I am a little puzzled by the failure to discuss outcomes in terms of mathematical expectation. And of course, the author knows more than I ever will about this. Hence: If our activity might just trigger a sequence of events leading to human extinction...(in other words such a sequence is conceivable and credible) then even if the risk is low as estimated by our (weak) ability to assess such risk, then the outcome is surely so hideous that if our policies are taking us in a direction that makes such an outcome more likely (even if we are not sure by how much) then there is cause for caution and re-examination of policy. It seems to me that our situation at present is of this form. Despite our poor understanding and the fact that things aren't 'settled' (as if they ever will be) this unsettled 'knowledge' is all we have and we have to take it seriously, most particularly if the possible outcomes are ghastly. We can't just wait for better science.

61 points by T-A 12y ago

"The crucial scientific question for policy isn't whether the climate is changing. That is a settled matter: The climate has always changed and always will. Geological and historical records show the occurrence of major climate shifts, sometimes over only a few decades. We know, for instance, that during the 20th century the Earth's global average surface temperature rose 1.4 degrees Fahrenheit. Nor is the crucial question whether humans are influencing the climate. That is no hoax: There is little doubt in the scientific community that continually growing amounts of greenhouse gases in the atmosphere, due largely to carbon-dioxide emissions from the conventional use of fossil fuels, are influencing the climate. There is also little doubt that the carbon dioxide will persist in the atmosphere for several centuries. The impact today of human activity appears to be comparable to the intrinsic, natural variability of the climate system itself... Society's choices in the years ahead will necessarily be based on uncertain knowledge of future climates. That uncertainty need not be an excuse for inaction." Much better than I expected of the WSJ. If it consistently took this line instead of buying into absurd conspiracy theories or claiming snow in January means climate change is a hoax, our national discourse would be much healthier, on both sides.

hristov 12y ago

FUD is not only for operating systems anymore.

quink 12y ago

> Dr. Koonin was undersecretary for science in the Energy Department during President Barack Obama's first term and is currently director of the Center for Urban Science and Progress at New York University. His previous positions include professor of theoretical physics and provost at Caltech, as well as chief scientist of BP, BP.LN +0.42% where his work focused on renewable and low-carbon energy technologies. > We are very far from the knowledge needed to make good climate policy Complete and total horseshit. Even if you'd only assume that the scientists are 90% right any good actuaries will tell you that you should spend about 90% on measures that back up what they've put forward. Hacker News, I expected something better than this in the #2 spot. Here, read this: http://www.ipcc.ch/report/ar5/ http://www.ipcc.ch/report/ar5/ Or this: http://en.wikipedia.org/wiki/Global_warming http://en.wikipedia.org/wiki/Global_warming Or this: http://en.wikipedia.org/wiki/Ocean_acidification http://en.wikipedia.org/wiki/Ocean_acidification Or this one is excellent: http://www.skepticalscience.com/ http://www.skepticalscience.com/ Edit: Alright, here we go with the downvotes for calling out bullshit regarding climate change on Hacker News. Well, it's not like I expected any better. Next I expect a replies either trying to argue random points about how there were forests in Greenland in the middle ages or some pretensions about being open-minded. While still barely having a grasp of a periphery of relevant facts. But that's OK, the warriors having upvoted this to the top immediately know best. Or at least as well as Murdoch, publisher of the WSJ who has recently installed a prime minister in Australia who called climate change 'crap' and has abolished a carbon tax a minute fraction of those found in the rest of the OECD.

triangleman 12y ago
What's your point? That Dr. Koonin is not a trustworthy source because he worked for BP?
- lotsofmangos 12y ago
  I would take the opinions of an industry expert with a large pinch of salt on the subject of negative externalities of the industry they are involved in, no matter what the industry.
- Daishiman 12y ago
  Yes?
igravious 12y ago
Whatever. I am sick to the back teeth of "the sky is falling!" rhetoric. I refuse to live in mortal fear for the future of humanity. The climate will change, big deal, we'll adapt -- the range of habitats humans inhabit far exceeds the variation in climate that individual habitats will experience. On the list of things to worry about climate change should be way down. But wow, you're so vocal -- because you feel that it is an existential threat. Newsflash, it ain't. Homelessness is a bigger problem. Ditto poverty and starvation. I _welcome_ the push back against the drumbeats and rhetoric and hope climate change disappears off the political agenda entirely. Some hope.
- Squarel 12y ago
  You don't think homelessness/starvation/food security/water security will be affected by any future changes in climate?
- quink 12y ago
  It is a bit of an existentialist threat. It's one of the possible answers to the Fermi paradox. Why haven't we met anyone? Because they boiled themselves to bits before they could interstellar space. Which, inherently, requires huge amounts of energy, possibly enough to change climates. I can't think of things more fundamental to existence or non-existence in this universe than it being the wrong temperature.

tlb 12y ago

I'm surprised by the finest possible resolution quoted, a 60 mile grid. It corresponds to about 55,000 cells covering earth (times maybe 100 altitude bands). That's not a large amount of memory. I assume the limitation is that all those cells have to be simulated in small time slices for 100 years, and the necessary time slice would scale inversely with the grid size, so computation is O(n^3) on the inverse size of the grid. Can someone comment on what kind of computer it would take to halve the size of the grid?

tjradcliffe 12y ago
There are usually quite a bit fewer than 100 altitude slices. There may be as few as 10: http://www.ipcc-data.org/guidelines/pages/gcm_guide.html http://www.ipcc-data.org/guidelines/pages/gcm_guide.html Simulations are typically done in one day time-steps or less. The thing is, there is a lot of physics going on in each cell, and in some respects reducing the cell size makes things more problematic rather than less. For example, the effects of a supercell thunderstorm can dominate the atmosphere over tens of kilometers. With a 100 km (60 mile) scale you can plausibly average over those effects within a cell, as you can reasonably claim that most such "local" phenomena will be happening well away from cell boundaries. So as you reduce the cell size, you start having to think about the internal details of local disturbances that you were previously averaging away and hoping to catch in your overall parameterizations, and the model complexity goes up tremendously, likely without becoming a whole lot more accurate. Even at these large scales the amount of physics that goes on within a single cell is huge, and getting all the heat and mass balances right is fantastically difficult, which is where a lot of the computational power goes. So it isn't really a question of halving the grid size while keeping the physics the same, because you are going to have to substantially revise your model to accommodate the new scale. I'm sure this work is ongoing, but it's extremely complex and difficult.
- rwallace 12y ago
  What sort of physics calculations can you do within a cell? I would have expected the data structure for a cell to contain a handful of scalar parameters (e.g. temperature, pressure, humidity, velocity vector) related by a few scalar equations - a negligible amount of computation. It sounds like there's quite a few orders of magnitude more stuff going on within a cell than I would have expected. What am I missing?

tjradcliffe 12y ago

Steve Koonin is an incredibly smart guy with a huge amount of experience in climate and energy issues, and is saying things in this article that any competent computational physicist who has looked into climate modelling believes. Compare for example my own short take on the same issues, written two years ago: http://www.tjradcliffe.com/?p=886 http://www.tjradcliffe.com/?p=886 You'll see basically similar concerns raised. If you're seriously wedded to the idea that consensus is important to the science, you should dig up the independent opinions of a few other computational physicists (not climate scientists, who are not computational physicists). Having done so, you might find that there is a consensus amongst computational physicists that climate models are problematic in ways that make them questionable guides to policy, although most of us will also say that we should be concerned about the amount of garbage we are dumping into the atmosphere (and there are reasons to want to get off fossil fuels that go beyond the climate change argument.) Denialists have poisoned the public discourse on climate change, but Warmists have unfortunately responded by digging in their heels in a particularly anti-scientific way. I hope Koonin's piece will help bring the scientific discussion back to fundamentals, and perhaps decouple the policy discussion from models a bit. For example: we know that carbon taxes work pretty well in reducing CO2 emissions (http://www.theglobeandmail.com/globe-debate/the-insidious-truth-about-bcs-carbon-tax-it-works/article19512237/ http://www.theglobeandmail.com/globe-debate/the-insidious-tr...) and we know that carbon taxes can be used to reduce corporate and income taxes. So anyone who is opposed to carbon taxes is necessarily in favour of higher corporate and income taxes. This is a policy discussion that can and should be had independently of any detailed climate model results, and I invite everyone who is in favour of higher corporate and income taxes to chime in here in support of their position, and explain why those taxes are so much better than the carbon taxes that could partially replace them.

quink 12y ago
http://www.skepticalscience.com/climate-models-intermediate.htm http://www.skepticalscience.com/climate-models-intermediate.... http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/jul/21/realistic-climate-models-accurately-predicted-global-warming http://www.theguardian.com/environment/climate-consensus-97-... And can you please stop with the 'Warmist' label? It's stupid, about as much as 'denialist' is narrow for the veritable zoo of opinions - educated or uneducated - that's sprung up in the public discourse. I've also read your post and 1-2 W/m2 does sound like very little. However, and I quote from Wikipedia: > Of the ~340 W/m2 of solar radiation received by the Earth, an average of ~77 W/m2 is reflected back to space by clouds and the atmosphere, and ~23 W/m2 is reflected by the surface albedo, leaving about 240 W/m2 of solar energy input to the Earth's energy budget. That's a change of 0.5%. Doesn't sound like much, does it, but at 273 K that corresponds to about 1.5 degrees already. At the upper end of that and 300 K it's 2.5 degrees. Sure, it's simplistic and it's how to keep it quite that straightforward, but to see that number and be ignorant enough of the context to trivialise it and call it not a big deal is pretty disingenuous. Sure, a 2.5 K (or something like it) rise isn't going to bring the downfall of civilisation per se. But there's more to it than that. And, mind you, 2.5 K is at the lower end of IPCC projections, so there's evidently a lot more ground to cover than the simplistic numbers mentioned here.

j2kun 12y ago

"Settled" is not a word you can use when describing any science. Medicine is not settled, nor is physics or computer science. But we can still glean useful insights from the evidence and experiments we have done. While it's wrong to claim climate science is settled, I can't recall any credible figure who said that it was. So to me this seems like a bit of a straw man.

qthrul 12y ago

Science is that which explains and predicts. If you are missing either of these attributes -- you are in the realm of legends, folklore, and farmer's almanacs.

haberman 12y ago

"Climate Science Is Not Settled" is an irresponsible title IMO when the main points of contention in public discourse are whether anthropogenic climate change is even real or not, and action vs. inaction. It's a good article and I'm happy to see it (assuming the information is accurate). But deniers will point to the title to argue that the whole things is a hoax and that we should do nothing. I'm sure the phenomenon of "Warmists" is a real thing too, and something to watch out for. But it's incredibly hard to talk about the subtle points presented in this article when so many people refuse to believe that anything is happening at all. It's like trying to debate foreign policy with someone who thinks that 9/11 was an inside job.

lutorm 12y ago

I always thought that when people used the word "settled" in connection to climate change they were referring to the question of whether humans have influenced climate. Even though this article dismisses that question as "yeah there's little doubt about that", this is precisely what plenty of people have been arguing is not the case. So this article seems a lot like moving the goal posts to me. Obviously climate science as a whole isn't "settled", any more than any other science is "settled".

hencq 12y ago
Yeah I agree. The article was actually good and calls out very reasonable criticisms against current climate science. However the headline makes it seem the debate on whether humans influence the climate isn't settled.
- lotsofmangos 12y ago
  That is most likely intentional. The headline was probably come up with from on high before any experts were even solicited to write the piece.
- ende 12y ago
  One thing that the author points out is that the impact by humans is relatively small (compared to natural sourcing), and that natural variation is both vast and frequent.

e40 12y ago

I was hoping to find something about acidification of sea water, caused by CO2. Even if the warmth of the earth isn't caused by us, it seems like the acidification of the ocean might be. A similarly skeptical look at this would be welcomed.

ende 12y ago
Please, this debate is contentious enough without bringing SQL-vs-NoSQL into it.

Daishiman 12y ago

Wow. I am amazed that an article filled with such a vast amount of FUD is frontpaging. But let's go point-by-point, lest the science described in thousands of papers of climate research get lost in the cloud of false skepticism, shall we? > The models roughly describe the shrinking extent of Arctic sea ice observed over the past two decades, but they fail to describe the comparable growth of Antarctic sea ice, which is now at a record high. The science of why Antarctic sea ice extent is growing is perfectly well known: the discharge of melting cold water from the Antarctic glaciers forms ice as it hits the coastal winds of the continent. That the models don't necessarily account the extent of this is almost irrelevant, since the sea ice extent has a very minute impact on climate patterns. Let us note that this is a not-at-all subtle piece of FUD that would appear to account that Antarctic sea ice is compensating for Arctic melting. It's not. There's over 500 Gt of yearly glacier loss in the Antarctic, and the sea ice extent which is, at most, a few meters thick, is absolutely minuscule in comparison to the amount of additional water dissolving into the sea from kilometers-thick walls of ice. Also, the topic has been reasonably well-studied, and the changes in the atmosphere are more than enough to account for the observed effects. > Even though the human influence on climate was much smaller in the past, the models do not account for the fact that the rate of global sea-level rise 70 years ago was as large as what we observe today—about one foot per century. It is most definitely increasing, and it is accelerating rapidly, especially if the West Antarctic Ice Sheet accelerates its collapse (http://www.skepticalscience.com/sea-level-rise.htm http://www.skepticalscience.com/sea-level-rise.htm). The fact that we have been observing linear trends thus far doesn't mean that we'll continue to observe them; evidence points that we're in the beggining of an exponential loss of ice. > A crucial measure of our knowledge of feedbacks is climate sensitivity—that is, the warming induced by a hypothetical doubling of carbon-dioxide concentration. Today's best estimate of the sensitivity (between 2.7 degrees Fahrenheit and 8.1 degrees Fahrenheit) is no different, and no more certain, than it was 30 years ago. And this is despite an heroic research effort costing billions of dollars. This is, again, FUD. First of all, the radiative forcing produced by CO2 is well-known and established by physics. It is known that the Earth's albedo is decreasing, and the certainty that out lower bounds are erroneous has increased substantially. Moreover, we are now aware of potential feedback loops that we didn't know about. It's interesting that he's never mentioning the Big One: the potential for frozen clathrates in Siberia and the Arctic to release methane that would trigger a certain mass extinction event. > A transparent rigor would also be a welcome development, especially given the momentous political and policy decisions at stake. That could be supported by regular, independent, "red team" reviews to stress-test and challenge the projections by focusing on their deficiencies and uncertainties; that would certainly be the best practice of the scientific method. But because the natural climate changes over decades, it will take many years to get the data needed to confidently isolate and quantify the effects of human influences. So, in his opinion, the models clearly described in papers, the data publicly available by NASA and dozens of different government organizations is not enough? A 3000-page report summarizing the findings of hundreds of papers, with multiple, independently corroborated lines of evidence using different data sets isn't enough? This an obvious attempt to discredit climate scientists. I would suggest anyone who has a shred of doubt as to the integrity of these people that you just walk into any Atmospheric Sciences Department of your local university and buy any teacher a cup of coffee and have a chat. Seriously, they will talk your ear off about their research. As a personal note, most climate scientists are the kind of people smart enough and capable enough to be making decent cunks of money outside of their chosen field (a combination of knowledge in physics, chemistry, and computational modeling are desired skill in many lucrative fields). They're not doing this for the money, or the recognition, and it pains me that people are willing to believe the ramblings posted in a Murdoch-owned newspaper on the matter without willing to question the economic interests behind climate denialism. But I digress. > But climate strategies beyond such "no regrets" efforts carry costs, risks and questions of effectiveness, so nonscientific factors inevitably enter the decision. These include our tolerance for risk and the priorities that we assign to economic development, poverty reduction, environmental quality, and intergenerational and geographical equity. There's something that should be really important, which people raised on the typical media diet of "two sides of the story" and "fair and balanced" should understand: We're not debating whether climate change is something serious or not. The current debate is whether we're facing a future where "merely" the following things will happen: * An acidified ocean where almost all fish stocks will collapse, with a PH that will make the growth of crustaceans and zooplankton difficult, to say the least. * Megadroughts will become a common occurency, as will increased levels of flooding resulting in losses of crop efficiencies above 10% * All of the planet's ecosystems will be permanently affected, making the harvesting of crops such as coffee and cocoa a thing of the past * An acceleration into our current period of mass extinction, with unforeseen consequences Or, nn the other extreme, quite literally, we have a scenario of a degradation of the Earth's biosphere to the point where humans face complete extinction within the next century. The last scenario could be triggered by one of the many feedback cycles which include the sudden release of methane clathrates, an exponential collapse of the West Antarctic Ice Sheet leading to the rapid increase in sea level of multiple feet, or just sufficiently large megadrought events in enough places in the globe to disrupt the global food supply chain. Hell, just an increase in temperature of 4 degrees C ("just") would be enough. My final rebuttal: > Individuals and countries can legitimately disagree about these matters No, they cannot, unless they're legitimate experts in climate science with an understanding that actually improves upon what we have, they have squat to say on the science of it. This fake notion that anyone can have an opinion on knowledge that's in flux is intellectually dishonest. Experts are allowed to disagree. Us laymen have almost nothing to add to the conversation, unless we want to gamble with our own demise. Anyone who thinks otherwise is plainly ignorant of the science, and that's not a point in discussion. The only thing this discourse does is play down the supposed "alarmism" of the situation. I don't know man, if you think that a potential, non-trivial chance of the collapse of the biosphere isn't something to be alarmed of, then I don't know what is.

grifpete 12y ago

It seems that the article has a simple thesis. a) climate is hard b) human activity is affecting it but because it's hard it's tough to know how much c) hence it's difficult to know what the correct policies should be. As an economist might say - without clarity on the positive, it's challenging to resolve the normative. But I am a little puzzled by the failure to discuss outcomes in terms of mathematical expectation. And of course, the author knows more than I ever will about this. Hence: If our activity might just trigger a sequence of events leading to human extinction...(in other words such a sequence is conceivable and credible) then even if the risk is low as estimated by our (weak) ability to assess such risk, then the outcome is surely so hideous that if our policies are taking us in a direction that makes such an outcome more likely (even if we are not sure by how much) then there is cause for caution and re-examination of policy. It seems to me that our situation at present is of this form. Despite our poor understanding and the fact that things aren't 'settled' (as if they ever will be) this unsettled 'knowledge' is all we have and we have to take it seriously, most particularly if the possible outcomes are ghastly. We can't just wait for better science.