Should, in my opinion, be composed of 4 major parts:
1) A carbon price. Key features: that it is implemented soon, that it has a believable upward trajectory of price, and that it is adjustable in the future as politics, science, and economics warrant.
I would prefer a tax to cap-and-trade, and a floor/ceiling cap-and-trade to a borrowing/banking cap-and-trade. I would like the revenues from the instrument to flow mostly back to the people: eg, cap-and-dividend - I'm not particular about mechanism (per person direct payment, payroll tax reduction) as long as it is a progressive cash return to compensate the somewhat regressive nature of the carbon price.
2) Non-market corrections: eg, the landlord-tenant market failure where the landlord has no incentive to invest in energy efficiency upgrades to reduce tenant energy rates, and the non-transparency of the market means tenants don't have full information up-front to choose less expensive buildings. I think a key issue here is smart-growth and urban planning. Also, eliminating the mortgage deduction for homes above a certain square footage and other such subsidies of energy-expensive behavior. Transmission system upgrades would be here too.
3) R&D: Research into new technologies, pilot projects, etc: fusion, advanced fission, carbon sequestration, advanced batteries, advanced transmission systems, geothermal, tidal, other energy systems, energy efficiency research, and even urban planning research.
4) International engagement: Obviously, entering a post-2012 Kyoto would work, but a "harmonized" set of national policies could be an alternative.
Other issues involve other gases, black carbon, albedo issues, education, improved climate research, etc.
Tuesday, February 24, 2009
Saturday, February 7, 2009
Inconvenient Truth Review
Review ported over from my personal blog. Caveat: the review was written at the time the movie came out, and other than deleting one paragraph for mentioning specific people I know, I haven't updated any of the science.
Title: An Inconvenient Truth
Director: David Guggenheim
Star: Al Gore
Website: www.climatecrisis.net
I'm going to concentrate mostly on the science here, though I will start with a few sentences on the non-science. The first 30 seconds of the movie Gore's monotone voice over about placid waters and peaceful trees made me worry that the movie was going to be very very painful. Fortunately, that got a _lot_ better fast. For the most part I felt that the interludes about Gore's life and family were good for giving the documentary a human feel, though not so relevant to climate change. And I felt the political touches were only a little bit too much, though if I were Gore I would have tried to err the other way in hopes that it didn't turn off conservatives/republicans. And Gore really came through as human, touching, humorous, thoughtful, and all those characteristics I'd want in a president. Alas. Sigh. But then, I always liked Gore even back when the media somehow all came to the weird conclusion that he was wooden and robotic (he gave a fine graduation speech at MIT).
Okay. To the science! First: The Sally&Global Warming story was _great_. Oddly, I think it was a better explanation than the graphic that came before it of sun beams bouncing off the planet and getting trapped by the greenhouse gas (GHG) barrier. But then, one of the things that is on my todo list is to come up with an actually correct description of the greenhouse effect, which is harder than you think, because step 1: the greenhouse effect is totally unlike an actual greenhouse. It is more important that greenhouses stop convection than that they trap radiation. A "thin layer" being "thickened" which is a description that Gore uses is kind of correct, in that one description of the effect is that you radiate heat to space from a higher altitude when you have more GHGs - of course, the graphic was misleading, but anyway. Minor point.
Two: Of course Gore showed the Mauna Loa CO2 graph. You've got to. But his explanation about the earth breathing in was a little wrong: he pointed out correctly that the northern hemisphere has more landmass and therefore vegetation than the southern. Which would lead one to naturally assume (as does Gore) that the northern hemisphere seasonal signal would dominate the southern one: except it turns out that there is a mixing period on the scale of a year or two between the two hemispheres. So that if you actually look at the data, at Mauna Loa there is a CO2 peak in May and a trough in September or so (eg, breathe in as plants grow, breathe out as they decay), and in the southern hemisphere while the cycle is much smaller and sometimes disappears in the noise, it looks like there is an October peak and a March trough. Note that my estimation comes from eyeballing the data, and I didn't subtract the linear trend out. But, anyway, minor point.
Three: Lots of pretty pictures (or depressing pictures) of disappearing glaciers. Of course, any individual glacier isn't evidence: glaciers advance and retreat all the time. Its the statistics, and he didn't show the statistics. But that is fine, because the statistics do support his point, which is that the vast majority of glaciers are retreating fast, and people should do their glacier tourism now because by the time we're all retired they'll be a lot harder to find. He also showed calving glaciers, and implied that that was global warming caused, whereas all glaciers calve on occasion. The point is that global warming is accelerating the process, so here is one of the cases where he didn't _state_ a lie, but the implication was misleading, but the takeaway point was true.
The "40% of the world's population gets their water from spring systems which are half glacier fed" is a frightening statistic. I knew the "big picture" argument (eg, a lot of countries depend on the Himalayas for their fresh water) but I hadn't internalized the numbers before.
Ice cores give a yearly record of CO2 trapped in bubbles, and Temperature records by oxygen isotope analysis. True. (there's some art in the temperature reconstruction, since basically what you are measuring is the O18:O16 ratio in historical snowfall, and that ratio is determined in part by condensation at the poles, and in part by evaporation in the oceans, and depending on air circulation patterns you are measuring the ocean surface temperature at different locations on the globe, but anyway. Cool science).
He claims you can see the Clean Air Act in Antarctic ice cores. Realclimate.org claims this is false, and I believe them.
He shows a 1000 year Northerm Hemisphere temperature reconstruction. He doesn't show the uncertainty bars on it (there are several reconstructions). Again, it is true that the reconstruction exists, and it is true that we are (almost certainly) warmer than any time in the past 1000 years and getting even warmer fast, but it would be more accurate to show a whole bunch of overlaid reconstructions because proxy temperature analysis is _hard_ and different people get different results (though they all have the same general final conclusion). More iffy is that he says "look - CO2 and temperature both go up at the end of the 1000 year period", when our best attribution work suggests that the 1880 to 1940 warming was mostly natural, and only the 1970 to present warming is mostly CO2 induced.
When he shows 650,000 years of history he _states_ that the CO2 and temperature relationship is very complicated, but so quickly that I think most viewers would miss it. At the end of the period, he shows CO2 rising to 2050 - while there are no #s on the graph, it looks suspiciously like CO2 reaches 500 ppm by 2050, which is on the high end of projections. (edit: looking at a paper I'm coauthor on, we actually project 400 to 600 ppm in the business as usual case, so if my guess of 500 from looking at Gore's graph was right, then in fact, he was right on the money). Anyway, he then _implies_ but does not state that if a 60 ppm difference (220 to 280) is the difference between an Ice Age and an interglacial, then what is the _huge_ difference between 280 ppm and 500 ppm going to do? Which is again, right in big picture - we are going into seriously uncharted atmospheric territory - but it is very unlikely that 500 ppm will actually cause a temperature change as big as the Ice Age/interglacial difference, which, after all, is dependent on all sorts of things like orbital radiative forcing changes and serious feedbacks from retreating ice caps of a magnitude that we can't see because there just isn't that much ice left. Of course, we aren't likely to stop at 500, so we may very well see by a world "one ice age to interglacial unit" warmer by 2200 or so... which is kind of scary...
He cites 2005 as the hottest year in recorded history. It is actually kind of tied with 1998. Of course, 1998 was an El Nino year, and so expected to be anomalously hot, whereas 2005 was a "normal" year, and so the heat is more disturbing. Minor point.
The chart he showed of ocean temperatures was, well, kind of ick in my opinion The first graph was "predicted natural variability" using a model. The 2nd was "predicted temperatures under greenhouse warming". The 3rd (falling inside the 2nd, of course) was experimental data. Basically, my issue is that our ocean heat models aren't so good. I'm perfectly fine with the conclusion: the evidence is the ocean is warming to an extent that can't be explained with natural variability, but I don't think we need to resort to model data for that.
His hurricane stuff was mostly good: obviously we can't attribute any individual hurricane to global warming, but we do for the most part expect hurricanes to get more powerful with warmer oceans, though it is complicated. His citation of 10 typhoons hitting Japan was not as good, as I believe we currently have little evidence that _frequency_ of Pacific cyclones have increased. The _intensity_ of Pacific cyclones _has_ gone up, and both the intensity and frequency of _Atlantic_ cyclones have gone up (statistically), but this research is kind of new and still not fully accepted.
Increase in precipitation (on average), likely increase in high precipitation single events, shifting of precipitation such that you get both more floods and more drought: all matches the current expectations, though regional predictions and precipitation in specific are all really hard to do.
He _shouldn't_ in my opinion have showed the "damage from severe weather events" graph, as that is probably more due to increase in property to _be_ damaged than increase in actual events. (the "increase in major flood events in Europe" graph was fine, though, as long as "major flood" is measured by water levels and not by economic impact)
I don't know if we attribute the sub-Saharan drought to global warming. Neither did he, exactly, but he implied it. I would certainly believe it is related, but again, our regional predictions are for the most part pretty bad.
His "tundra travel days" chart is misleading because I believe that it isn't that it is physically impossible to drive across the tundra when it isn't frozen, but rather that environmental regulations restrict travel on non-frozen tundra because it permanently damages the ecosystem. He kind of implied it was from trucks getting stuck in mud. Which I'm sure happens, but there is technology to deal with that. This does, of course, still show how much the arctic is warming...
He cited 5 degrees fahrenheit as the low end of predictions. I would have said 3-4 degrees as the low end for 2100. He didn't state a date. (in fact, that was a recurrent weakness: he often didn't give time scales for impacts) (the high end for 2100 would be on the order of 10-12 degrees, with a median of 7 or so)
Arctic Ocean ice free in the summers by 2050: I can believe that. I also hear that the portion of the Arctic where they released navy sub data on ice thickness was nicknamed "the Gore Box" because it was Gore's pet project.
He talked about the thermohaline collapse, and the Younger Dryas event. He implied we might need to worry about Greenland causing a recurrence. While I do worry about the thermohaline circulation shutting down, I don't think we need to worry about it causing a European ice age: if anything, it will counteract warming in Europe and keep Europe's climate more temperate. I worry more about the massive changes in regional weather patterns and ocean ecosystems that would occur after such a collapse.
His invasive species graph in Switzerland was misleading, though we do believe that invasive species thrive in disrupted environments which changing climate will cause. But today most of the disruptions are caused by non-global changes, or by people physically carrying the disruptive species from one part of the world to another. (bark beetles in Alaska is an exception)
He also listed infectious diseases and didn't ever draw a clear link to global warming. Probably because there aren't clear links, with the except of some issues like the mosquitoes and high altitude city issue.
Example of a caveat: Coral reefs bleaching will occur because of "warming and other factors". So the "other factors" is in there, but if you aren't watching for it, you won't notice it. Of course, enough warming and we won't need other factors to kill off the coral, but right now coral is dying because of warming on top of other strains.
He spends a lot of time showing the impacts of 20 feet of sea level rise. Most of the science he talks about is good, but he doesn't mention the time scale: it is highly unlikely that we will see more than 3 feet of sea level rise this century. Of course, Greenland is kind of precarious in that the reason why the center of Greenland is cold enough to maintain an ice cap is because there is so much ice there that the top of the cap is at a high (and therefore cold) altitude. Which means that if the center of Greenland ever warms enough to start general melting... well, then you get a decrease in height, followed by warming because it is at lower elevation, followed by... well, you get the picture. One professor I know thinks that once that process starts, all of Greenland will go in "a few decades" which is a scary thought. But again, I don't think that will happen this century. Then again, if you'd asked me 3 years ago, I would have said the net contribution to sea level rise from Greenland and Antarctica would be near zero, and recent evidence (which Gore cites: the whole water tunneling down and lubricating the bottom of the ice) suggests that in fact they will contribute several centimeters or more to the sea level rise that we'd predicted from thermal expansion and glacial melt (which was 20 cm to 1 m or so).
Then he talks about the scientific consensus. Again, big picture is true: there is a pretty overwhelming scientific consensus which is _not_ reflected in the popular press which often hunts a skeptic down for "equal time" quotes. But the study he cites which surveyed 960 studies and found no negative evidence (Noami Oreskes, Science or Nature, I think) - well, I read that study when it came out and despite agreeing with the conclusion I found the methodology dubious.
When Gore got to talking about "choosing between the economy and the environment" I thought he was being a bit disingenous when he said that doing the right thing would generate jobs and wealth. While there probably are a few real "negative cost" options out there, and while certainly individual companies can profit greatly off of environmental standards, and while there may be a significant amount of "low-hanging fruit" that we could grab if there was just a small carbon price, to really deal with the climate problem will take significant resources which, even if it doesn't hurt the economy directly (which it might, through higher energy prices) will at the least be drawing resources from other research areas and problems. Of course, we'd be improving the economy of the future by delaying the necessity of moving 100 million plus people out of coastal cities in the 22nd century. But anyway.
He compared US mileage standards to Chinese mileage standards. I wonder if Chinese vehicles are actually meeting those standards? But yes, the US fleet average should be _much_ higher than it is, we're just being wasteful. But I would prefer a regulation that didn't look like CAFE, which regulates "fleet average", which ironically means for every high mileage car a company sells it can sell a low mileage one. I'd prefer a regulation that penalized low mileage cars/subsidized high mileage cars regardless of what the fleet average was. But if CAFE is all we have, we should raise CAFE. Especially on SUVs. Anyway...
Gore then went into optimistic mode, which I think is good because you want to make people leave the movie thinking that they can do something, because going "from disbelief to despair" isn't very useful. However, his citation of the "wedge paper" (Pacala & Socolow, Science, 2005) was... well... okay, _everyone_ cites the paper now because it entered the popular scientific consciousness, but I think it downplays the difficulties in a) implementing the wedges, and b) going beyond 2050. I was interested to see that 1) Gore didn't include any of the nuclear wedges from the paper, but 2) he _did_ include CO2 sequestration and even drew attention to it by saying "we'll see more of this". CO2 sequestration (at the gigaton scale) is basically taking CO2 from coal plants and shoving it underground. Controversial in some environmental circles. Most of the people I know accept it as part of a "bridging strategy" to slow down CO2 growth in the next few decades until we get better solutions.
He also talked about "reducing personal carbon emission to zero". This is practically impossible, unless he is talking about using carbon offsets like Carbonfund.org, which are... kind of fuzzy. Though better than nothing, I guess. I occasionally think about starting to buy them myself, but haven't yet. I think that real personal reductions and persuading government to make regulations are both much better than offsets, if possible.
"At stake: our ability to live on this earth and continue as a civilization": I think this statement was exaggerated. Global warming might be very, very bad but I don't think it will be civilization ending.
Other notes:
Good quotes from Churchill, Mark Twain, and someone else famous (Sinclair?). I wish I had been fast enough to write them down.
The tobacco analogy I thought was powerful: we don't like admitting that we're doing something wrong until it really slams us in the face, and of course it the tobacco issue was very personal in his case. The frog analogy was also good, though I have heard that frogs don't actually behave that way.
Good question about "How do we react when we hear warnings?"
Did Marburger really teach Gore in 6th grade???
Overall Impression:
Facts Cited: Good
Caveats Used: Fairly Good
Big Picture, eg, Man is Causing Global Warming, it will be bad, we should work on stopping it: Good, though I might have put in a little more uncertainty (it is _very likely_ to be bad)
Some of the implied bits in between the facts and the big picture, on the other hand, were kind of misleading. Also, while the caveats were good, you had to be paying attention to catch them.
Movie Overall: Good, well worth watching, and mostly scientifically accurate.
Title: An Inconvenient Truth
Director: David Guggenheim
Star: Al Gore
Website: www.climatecrisis.net
I'm going to concentrate mostly on the science here, though I will start with a few sentences on the non-science. The first 30 seconds of the movie Gore's monotone voice over about placid waters and peaceful trees made me worry that the movie was going to be very very painful. Fortunately, that got a _lot_ better fast. For the most part I felt that the interludes about Gore's life and family were good for giving the documentary a human feel, though not so relevant to climate change. And I felt the political touches were only a little bit too much, though if I were Gore I would have tried to err the other way in hopes that it didn't turn off conservatives/republicans. And Gore really came through as human, touching, humorous, thoughtful, and all those characteristics I'd want in a president. Alas. Sigh. But then, I always liked Gore even back when the media somehow all came to the weird conclusion that he was wooden and robotic (he gave a fine graduation speech at MIT).
Okay. To the science! First: The Sally&Global Warming story was _great_. Oddly, I think it was a better explanation than the graphic that came before it of sun beams bouncing off the planet and getting trapped by the greenhouse gas (GHG) barrier. But then, one of the things that is on my todo list is to come up with an actually correct description of the greenhouse effect, which is harder than you think, because step 1: the greenhouse effect is totally unlike an actual greenhouse. It is more important that greenhouses stop convection than that they trap radiation. A "thin layer" being "thickened" which is a description that Gore uses is kind of correct, in that one description of the effect is that you radiate heat to space from a higher altitude when you have more GHGs - of course, the graphic was misleading, but anyway. Minor point.
Two: Of course Gore showed the Mauna Loa CO2 graph. You've got to. But his explanation about the earth breathing in was a little wrong: he pointed out correctly that the northern hemisphere has more landmass and therefore vegetation than the southern. Which would lead one to naturally assume (as does Gore) that the northern hemisphere seasonal signal would dominate the southern one: except it turns out that there is a mixing period on the scale of a year or two between the two hemispheres. So that if you actually look at the data, at Mauna Loa there is a CO2 peak in May and a trough in September or so (eg, breathe in as plants grow, breathe out as they decay), and in the southern hemisphere while the cycle is much smaller and sometimes disappears in the noise, it looks like there is an October peak and a March trough. Note that my estimation comes from eyeballing the data, and I didn't subtract the linear trend out. But, anyway, minor point.
Three: Lots of pretty pictures (or depressing pictures) of disappearing glaciers. Of course, any individual glacier isn't evidence: glaciers advance and retreat all the time. Its the statistics, and he didn't show the statistics. But that is fine, because the statistics do support his point, which is that the vast majority of glaciers are retreating fast, and people should do their glacier tourism now because by the time we're all retired they'll be a lot harder to find. He also showed calving glaciers, and implied that that was global warming caused, whereas all glaciers calve on occasion. The point is that global warming is accelerating the process, so here is one of the cases where he didn't _state_ a lie, but the implication was misleading, but the takeaway point was true.
The "40% of the world's population gets their water from spring systems which are half glacier fed" is a frightening statistic. I knew the "big picture" argument (eg, a lot of countries depend on the Himalayas for their fresh water) but I hadn't internalized the numbers before.
Ice cores give a yearly record of CO2 trapped in bubbles, and Temperature records by oxygen isotope analysis. True. (there's some art in the temperature reconstruction, since basically what you are measuring is the O18:O16 ratio in historical snowfall, and that ratio is determined in part by condensation at the poles, and in part by evaporation in the oceans, and depending on air circulation patterns you are measuring the ocean surface temperature at different locations on the globe, but anyway. Cool science).
He claims you can see the Clean Air Act in Antarctic ice cores. Realclimate.org claims this is false, and I believe them.
He shows a 1000 year Northerm Hemisphere temperature reconstruction. He doesn't show the uncertainty bars on it (there are several reconstructions). Again, it is true that the reconstruction exists, and it is true that we are (almost certainly) warmer than any time in the past 1000 years and getting even warmer fast, but it would be more accurate to show a whole bunch of overlaid reconstructions because proxy temperature analysis is _hard_ and different people get different results (though they all have the same general final conclusion). More iffy is that he says "look - CO2 and temperature both go up at the end of the 1000 year period", when our best attribution work suggests that the 1880 to 1940 warming was mostly natural, and only the 1970 to present warming is mostly CO2 induced.
When he shows 650,000 years of history he _states_ that the CO2 and temperature relationship is very complicated, but so quickly that I think most viewers would miss it. At the end of the period, he shows CO2 rising to 2050 - while there are no #s on the graph, it looks suspiciously like CO2 reaches 500 ppm by 2050, which is on the high end of projections. (edit: looking at a paper I'm coauthor on, we actually project 400 to 600 ppm in the business as usual case, so if my guess of 500 from looking at Gore's graph was right, then in fact, he was right on the money). Anyway, he then _implies_ but does not state that if a 60 ppm difference (220 to 280) is the difference between an Ice Age and an interglacial, then what is the _huge_ difference between 280 ppm and 500 ppm going to do? Which is again, right in big picture - we are going into seriously uncharted atmospheric territory - but it is very unlikely that 500 ppm will actually cause a temperature change as big as the Ice Age/interglacial difference, which, after all, is dependent on all sorts of things like orbital radiative forcing changes and serious feedbacks from retreating ice caps of a magnitude that we can't see because there just isn't that much ice left. Of course, we aren't likely to stop at 500, so we may very well see by a world "one ice age to interglacial unit" warmer by 2200 or so... which is kind of scary...
He cites 2005 as the hottest year in recorded history. It is actually kind of tied with 1998. Of course, 1998 was an El Nino year, and so expected to be anomalously hot, whereas 2005 was a "normal" year, and so the heat is more disturbing. Minor point.
The chart he showed of ocean temperatures was, well, kind of ick in my opinion The first graph was "predicted natural variability" using a model. The 2nd was "predicted temperatures under greenhouse warming". The 3rd (falling inside the 2nd, of course) was experimental data. Basically, my issue is that our ocean heat models aren't so good. I'm perfectly fine with the conclusion: the evidence is the ocean is warming to an extent that can't be explained with natural variability, but I don't think we need to resort to model data for that.
His hurricane stuff was mostly good: obviously we can't attribute any individual hurricane to global warming, but we do for the most part expect hurricanes to get more powerful with warmer oceans, though it is complicated. His citation of 10 typhoons hitting Japan was not as good, as I believe we currently have little evidence that _frequency_ of Pacific cyclones have increased. The _intensity_ of Pacific cyclones _has_ gone up, and both the intensity and frequency of _Atlantic_ cyclones have gone up (statistically), but this research is kind of new and still not fully accepted.
Increase in precipitation (on average), likely increase in high precipitation single events, shifting of precipitation such that you get both more floods and more drought: all matches the current expectations, though regional predictions and precipitation in specific are all really hard to do.
He _shouldn't_ in my opinion have showed the "damage from severe weather events" graph, as that is probably more due to increase in property to _be_ damaged than increase in actual events. (the "increase in major flood events in Europe" graph was fine, though, as long as "major flood" is measured by water levels and not by economic impact)
I don't know if we attribute the sub-Saharan drought to global warming. Neither did he, exactly, but he implied it. I would certainly believe it is related, but again, our regional predictions are for the most part pretty bad.
His "tundra travel days" chart is misleading because I believe that it isn't that it is physically impossible to drive across the tundra when it isn't frozen, but rather that environmental regulations restrict travel on non-frozen tundra because it permanently damages the ecosystem. He kind of implied it was from trucks getting stuck in mud. Which I'm sure happens, but there is technology to deal with that. This does, of course, still show how much the arctic is warming...
He cited 5 degrees fahrenheit as the low end of predictions. I would have said 3-4 degrees as the low end for 2100. He didn't state a date. (in fact, that was a recurrent weakness: he often didn't give time scales for impacts) (the high end for 2100 would be on the order of 10-12 degrees, with a median of 7 or so)
Arctic Ocean ice free in the summers by 2050: I can believe that. I also hear that the portion of the Arctic where they released navy sub data on ice thickness was nicknamed "the Gore Box" because it was Gore's pet project.
He talked about the thermohaline collapse, and the Younger Dryas event. He implied we might need to worry about Greenland causing a recurrence. While I do worry about the thermohaline circulation shutting down, I don't think we need to worry about it causing a European ice age: if anything, it will counteract warming in Europe and keep Europe's climate more temperate. I worry more about the massive changes in regional weather patterns and ocean ecosystems that would occur after such a collapse.
His invasive species graph in Switzerland was misleading, though we do believe that invasive species thrive in disrupted environments which changing climate will cause. But today most of the disruptions are caused by non-global changes, or by people physically carrying the disruptive species from one part of the world to another. (bark beetles in Alaska is an exception)
He also listed infectious diseases and didn't ever draw a clear link to global warming. Probably because there aren't clear links, with the except of some issues like the mosquitoes and high altitude city issue.
Example of a caveat: Coral reefs bleaching will occur because of "warming and other factors". So the "other factors" is in there, but if you aren't watching for it, you won't notice it. Of course, enough warming and we won't need other factors to kill off the coral, but right now coral is dying because of warming on top of other strains.
He spends a lot of time showing the impacts of 20 feet of sea level rise. Most of the science he talks about is good, but he doesn't mention the time scale: it is highly unlikely that we will see more than 3 feet of sea level rise this century. Of course, Greenland is kind of precarious in that the reason why the center of Greenland is cold enough to maintain an ice cap is because there is so much ice there that the top of the cap is at a high (and therefore cold) altitude. Which means that if the center of Greenland ever warms enough to start general melting... well, then you get a decrease in height, followed by warming because it is at lower elevation, followed by... well, you get the picture. One professor I know thinks that once that process starts, all of Greenland will go in "a few decades" which is a scary thought. But again, I don't think that will happen this century. Then again, if you'd asked me 3 years ago, I would have said the net contribution to sea level rise from Greenland and Antarctica would be near zero, and recent evidence (which Gore cites: the whole water tunneling down and lubricating the bottom of the ice) suggests that in fact they will contribute several centimeters or more to the sea level rise that we'd predicted from thermal expansion and glacial melt (which was 20 cm to 1 m or so).
Then he talks about the scientific consensus. Again, big picture is true: there is a pretty overwhelming scientific consensus which is _not_ reflected in the popular press which often hunts a skeptic down for "equal time" quotes. But the study he cites which surveyed 960 studies and found no negative evidence (Noami Oreskes, Science or Nature, I think) - well, I read that study when it came out and despite agreeing with the conclusion I found the methodology dubious.
When Gore got to talking about "choosing between the economy and the environment" I thought he was being a bit disingenous when he said that doing the right thing would generate jobs and wealth. While there probably are a few real "negative cost" options out there, and while certainly individual companies can profit greatly off of environmental standards, and while there may be a significant amount of "low-hanging fruit" that we could grab if there was just a small carbon price, to really deal with the climate problem will take significant resources which, even if it doesn't hurt the economy directly (which it might, through higher energy prices) will at the least be drawing resources from other research areas and problems. Of course, we'd be improving the economy of the future by delaying the necessity of moving 100 million plus people out of coastal cities in the 22nd century. But anyway.
He compared US mileage standards to Chinese mileage standards. I wonder if Chinese vehicles are actually meeting those standards? But yes, the US fleet average should be _much_ higher than it is, we're just being wasteful. But I would prefer a regulation that didn't look like CAFE, which regulates "fleet average", which ironically means for every high mileage car a company sells it can sell a low mileage one. I'd prefer a regulation that penalized low mileage cars/subsidized high mileage cars regardless of what the fleet average was. But if CAFE is all we have, we should raise CAFE. Especially on SUVs. Anyway...
Gore then went into optimistic mode, which I think is good because you want to make people leave the movie thinking that they can do something, because going "from disbelief to despair" isn't very useful. However, his citation of the "wedge paper" (Pacala & Socolow, Science, 2005) was... well... okay, _everyone_ cites the paper now because it entered the popular scientific consciousness, but I think it downplays the difficulties in a) implementing the wedges, and b) going beyond 2050. I was interested to see that 1) Gore didn't include any of the nuclear wedges from the paper, but 2) he _did_ include CO2 sequestration and even drew attention to it by saying "we'll see more of this". CO2 sequestration (at the gigaton scale) is basically taking CO2 from coal plants and shoving it underground. Controversial in some environmental circles. Most of the people I know accept it as part of a "bridging strategy" to slow down CO2 growth in the next few decades until we get better solutions.
He also talked about "reducing personal carbon emission to zero". This is practically impossible, unless he is talking about using carbon offsets like Carbonfund.org, which are... kind of fuzzy. Though better than nothing, I guess. I occasionally think about starting to buy them myself, but haven't yet. I think that real personal reductions and persuading government to make regulations are both much better than offsets, if possible.
"At stake: our ability to live on this earth and continue as a civilization": I think this statement was exaggerated. Global warming might be very, very bad but I don't think it will be civilization ending.
Other notes:
Good quotes from Churchill, Mark Twain, and someone else famous (Sinclair?). I wish I had been fast enough to write them down.
The tobacco analogy I thought was powerful: we don't like admitting that we're doing something wrong until it really slams us in the face, and of course it the tobacco issue was very personal in his case. The frog analogy was also good, though I have heard that frogs don't actually behave that way.
Good question about "How do we react when we hear warnings?"
Did Marburger really teach Gore in 6th grade???
Overall Impression:
Facts Cited: Good
Caveats Used: Fairly Good
Big Picture, eg, Man is Causing Global Warming, it will be bad, we should work on stopping it: Good, though I might have put in a little more uncertainty (it is _very likely_ to be bad)
Some of the implied bits in between the facts and the big picture, on the other hand, were kind of misleading. Also, while the caveats were good, you had to be paying attention to catch them.
Movie Overall: Good, well worth watching, and mostly scientifically accurate.
Sunday, February 1, 2009
Ocean Acidification
"However, the role of acidification in this decline is far from settled. In the laboratory, Alina Szmant, a coral physiological ecologist at the University of North Carolina, Wilmington, and her colleagues found that neither low pH nor a lowered calcium carbonate concentration (which results from increased acidity and is considered key to calcification) slowed coral growth. Instead, calcium bicarbonate proved key, her team reported at ICRS. She faults previous lab studies because they used hydrochloric acid, not carbon dioxide, to lower the pH of the water in the calcification studies. Hydrochloric acid and carbon dioxide have different effects on seawater chemistry and bicarbonate concentration, she says. Her conclusion: "It's not clear that carbon dioxide enrichment will have negative effects on calcification rates.""
On the other hand, Glenn De'ath (what a name!) has done studies showing that corals are slowing growth:
A large-scale study in Australia's Great Barrier Reef has revealed that the rate at which corals absorb calcium from seawater to calcify their hard skeletons has declined precipitously in the past 20 years, slowing coral growth. The report, on page 116, provides empirical data that fuels concerns that increased carbon dioxide in the air is putting these diverse marine ecosystems at risk (Science, 4 May 2007, p. 678).
So, ocean acidification: this has become a favorite argument at WattsUp and other skeptic places:
1) "acidification" _is_ the appropriate term for something become more acidic, regardless of whether the pH is below or above 7. "today was 2 degrees warmer than yesterday" regardless of whether yesterday was -30 or 80. "becoming less alkaline" would also be correct, but is kind of awkward. "neutralization" is less awkward, but I would argue less correct than "acidification" because there is an end state of pH 7 implied by neutralization. (those who don't believe me, look up the term "urine alkalinization" in which raising urine's pH to 6.5 is called alkalinization).
2) as the oceans warm, CO2 becomes less soluble: all other things being equal, warming would result in natural alkanization. However, Henry's Law states than in equilibrium, ocean CO2 is proportional to atmospheric CO2 over Henry's coefficient. The coefficient hasn't increased nearly as much as atmospheric CO2 has, so the ocean is still a sink. (see the carbon cycle argument in this blog).
3) there are many examples in biochemistry and biology of pH sensitive organisms. The argument between the Szmants and the De'aths basically comes down to whether there are enough organisms sensitive to the rate of change we expect over the next decades to lead to significant ecosystem degradation. And even if acidification by itself doesn't reach a tipping point, there is still a question of whether it will add on top of other stressors like temperature changes and anoxia events and overfishing... I think the magnitude of this additional stress is still uncertain, but my guess is that it is large enough to be significant. More Szmant type studies would calm me down, though.
On the other hand, Glenn De'ath (what a name!) has done studies showing that corals are slowing growth:
A large-scale study in Australia's Great Barrier Reef has revealed that the rate at which corals absorb calcium from seawater to calcify their hard skeletons has declined precipitously in the past 20 years, slowing coral growth. The report, on page 116, provides empirical data that fuels concerns that increased carbon dioxide in the air is putting these diverse marine ecosystems at risk (Science, 4 May 2007, p. 678).
So, ocean acidification: this has become a favorite argument at WattsUp and other skeptic places:
1) "acidification" _is_ the appropriate term for something become more acidic, regardless of whether the pH is below or above 7. "today was 2 degrees warmer than yesterday" regardless of whether yesterday was -30 or 80. "becoming less alkaline" would also be correct, but is kind of awkward. "neutralization" is less awkward, but I would argue less correct than "acidification" because there is an end state of pH 7 implied by neutralization. (those who don't believe me, look up the term "urine alkalinization" in which raising urine's pH to 6.5 is called alkalinization).
2) as the oceans warm, CO2 becomes less soluble: all other things being equal, warming would result in natural alkanization. However, Henry's Law states than in equilibrium, ocean CO2 is proportional to atmospheric CO2 over Henry's coefficient. The coefficient hasn't increased nearly as much as atmospheric CO2 has, so the ocean is still a sink. (see the carbon cycle argument in this blog).
3) there are many examples in biochemistry and biology of pH sensitive organisms. The argument between the Szmants and the De'aths basically comes down to whether there are enough organisms sensitive to the rate of change we expect over the next decades to lead to significant ecosystem degradation. And even if acidification by itself doesn't reach a tipping point, there is still a question of whether it will add on top of other stressors like temperature changes and anoxia events and overfishing... I think the magnitude of this additional stress is still uncertain, but my guess is that it is large enough to be significant. More Szmant type studies would calm me down, though.
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