Sunday, March 28, 2010
Saturday, March 27, 2010
Thursday, March 25, 2010
The Economist on climate change science
Summary/excerpts of a recent Economist article on Climate change science, mostly for my own reference:
Full article here:
http://www.economist.com/displaystory.cfm?story_id=15719298
======
In any complex scientific picture of the world there will be gaps, misperceptions and mistakes. Whether your impression is dominated by the whole or the holes will depend on your attitude to the project at hand. You might say that some see a jigsaw where others see a house of cards. Jigsaw types have in mind an overall picture and are open to bits being taken out, moved around or abandoned should they not fit. Those who see houses of cards think that if any piece is removed, the whole lot falls down. When it comes to climate, academic scientists are jigsaw types, dissenters from their view house-of-cards-ists.
The defenders of the consensus tend to stress the general consilience of their efforts—the way that data, theory and modelling back each other up. Doubters see this as a thoroughgoing version of “confirmation bias”, the tendency people have to select the evidence that agrees with their original outlook.
No one doubts that carbon dioxide is a greenhouse gas, good at absorbing infra-red radiation. It is also well established that human activity is putting more of it into the atmosphere than natural processes can currently remove. Measurements made since the 1950s show the level of carbon dioxide rising year on year, from 316 parts per million (ppm) in 1959 to 387ppm in 2009. Less direct records show that the rise began about 1750, and that the level was stable at around 280ppm for about 10,000 years before that. This fits with human history: in the middle of the 18th century people started to burn fossil fuels in order to power industrial machinery. Analysis of carbon isotopes, among other things, shows that the carbon dioxide from industry accounts for most of the build-up in the atmosphere.
Disagreement is not with the level of C02 or that it comes from human activity. It is with the warming associated with a particular level of CO2. Problems:
Background natural climate cycles.
Climate is a complex non-linear system
Oceans can absorb heat and add inertia to the climate system, so atmosphere warms more slowly than expected.
On the data front: There are three records of land-surface temperature put together from thermometer readings in common use by climatologists, one of which is compiled at the Climatic Research Unit of e-mail infamy. They all show warming, and, within academia, their reliability is widely accepted. Various industrious bloggers are not so convinced.
Pure theory says that doubling Co2 will result in 1 degree C of warming, which is not so problematic. "climate sensitivity". However there are feedback effects that can increase this. The most important involve water vapour and clouds. Warming air will absorb water vapour (powerful greenhouse gas) which is a positive feedback loop for warming. There is scientific uncertainity about how much the water vapour adds, one estimate is 1.7 degrees C, up from the 1 degree C above.
Another point of contention: greenhouse warming should cause warming down below and cooling in the stratosphere. Earlier observations did not corraborate this, but now evidence is building up in favour.
Clouds have both a cooling effect (reflecting sunlight from the upper atmosphere), as well as a greenhouse effect. Sorting these two out to get the net is complicated.
Another source of evidence is the climate of the past, like ice ages and the associated CO2 and other factors that contributed to it. The temperature records of the past millenium is one particular hotspot of debate. Tree rings is one source of data. A 1998 Nature article found a 'hockey stick' shape for temperatures of the last century, mostly flat but with the blip towards the end of the 20th century. This paper is widely contested by sceptics. One contestation is that this curve does not account for the 'medieval warm period' ; when, it is believed, temperatures were as warm or warmer than now.
The most accurate recent climate data cannot be used easily for checking the quality of models because of complexities like aerosols in the atmosphere whose effects are not known well enough so their effect is parameterized in the model instead of being strictly modelled. This also leads to accusations that they are parameterised in such a way as to make the models show higher levels of warming.
Full article here:
http://www.economist.com/displaystory.cfm?story_id=15719298
======
In any complex scientific picture of the world there will be gaps, misperceptions and mistakes. Whether your impression is dominated by the whole or the holes will depend on your attitude to the project at hand. You might say that some see a jigsaw where others see a house of cards. Jigsaw types have in mind an overall picture and are open to bits being taken out, moved around or abandoned should they not fit. Those who see houses of cards think that if any piece is removed, the whole lot falls down. When it comes to climate, academic scientists are jigsaw types, dissenters from their view house-of-cards-ists.
The defenders of the consensus tend to stress the general consilience of their efforts—the way that data, theory and modelling back each other up. Doubters see this as a thoroughgoing version of “confirmation bias”, the tendency people have to select the evidence that agrees with their original outlook.
No one doubts that carbon dioxide is a greenhouse gas, good at absorbing infra-red radiation. It is also well established that human activity is putting more of it into the atmosphere than natural processes can currently remove. Measurements made since the 1950s show the level of carbon dioxide rising year on year, from 316 parts per million (ppm) in 1959 to 387ppm in 2009. Less direct records show that the rise began about 1750, and that the level was stable at around 280ppm for about 10,000 years before that. This fits with human history: in the middle of the 18th century people started to burn fossil fuels in order to power industrial machinery. Analysis of carbon isotopes, among other things, shows that the carbon dioxide from industry accounts for most of the build-up in the atmosphere.
Disagreement is not with the level of C02 or that it comes from human activity. It is with the warming associated with a particular level of CO2. Problems:
Background natural climate cycles.
Climate is a complex non-linear system
Oceans can absorb heat and add inertia to the climate system, so atmosphere warms more slowly than expected.
On the data front: There are three records of land-surface temperature put together from thermometer readings in common use by climatologists, one of which is compiled at the Climatic Research Unit of e-mail infamy. They all show warming, and, within academia, their reliability is widely accepted. Various industrious bloggers are not so convinced.
Pure theory says that doubling Co2 will result in 1 degree C of warming, which is not so problematic. "climate sensitivity". However there are feedback effects that can increase this. The most important involve water vapour and clouds. Warming air will absorb water vapour (powerful greenhouse gas) which is a positive feedback loop for warming. There is scientific uncertainity about how much the water vapour adds, one estimate is 1.7 degrees C, up from the 1 degree C above.
Another point of contention: greenhouse warming should cause warming down below and cooling in the stratosphere. Earlier observations did not corraborate this, but now evidence is building up in favour.
Clouds have both a cooling effect (reflecting sunlight from the upper atmosphere), as well as a greenhouse effect. Sorting these two out to get the net is complicated.
Another source of evidence is the climate of the past, like ice ages and the associated CO2 and other factors that contributed to it. The temperature records of the past millenium is one particular hotspot of debate. Tree rings is one source of data. A 1998 Nature article found a 'hockey stick' shape for temperatures of the last century, mostly flat but with the blip towards the end of the 20th century. This paper is widely contested by sceptics. One contestation is that this curve does not account for the 'medieval warm period' ; when, it is believed, temperatures were as warm or warmer than now.
The most accurate recent climate data cannot be used easily for checking the quality of models because of complexities like aerosols in the atmosphere whose effects are not known well enough so their effect is parameterized in the model instead of being strictly modelled. This also leads to accusations that they are parameterised in such a way as to make the models show higher levels of warming.
Wednesday, March 24, 2010
Saturday, March 13, 2010
Saturday, February 20, 2010
Kerala percussion
Vibhat was in India and invited us to join him while he was in Kerala. I went with Siddhu, since Priya and kid are at her parents place. Vibhat's mom organised a cool music concert at the house. The video of of this. As a matter of fact this is pretty rare footage. This particular instrument is not common and is rarely played in public. The musicians here are students from Kala Mandalam -- a university for traditional arts in Kerala. We visited the place later, pretty impressive.
Let me know what you think of the music:
Let me know what you think of the music:
Friday, February 19, 2010
The vegetable pushcart man as hero
As you drive on the streets of Bangalore you often come across vegetable pushcarts. These are flat 4 wheeled contraptions, loaded with vegetables and being trundled around the city. Sometimes its just piled high with tomatoes and potatoes, sometimes its a wide range of vegetables. Consider the life of the vegetable pushcart man:
-- the daily pollution and dust
-- being completely at the mercy of the weather ; from hot sun to sudden showers. Imagine trundling your way home maybe 5 kilometers away in one of Bangalore's thunderstorms in roads running full of water with your business day washed out.
-- reducing business as the big shops like Reliance undercut everyone else
-- negotiating Bangalore's traffic and intersections where to the man in the CAR the pedestrians and pushcarts are irritants to be honked angrily out of the way as they interrupt the smooth flow of traffic.
Despite all these obstacles, the pushcart man endures. Why does he do it? Does he go home to a loving family that makes it all worth it for him? Does he feel he has no choice? Or does drink do the trick? Where does he draw the strength from, to continue his useful but uneviable role? Does he fall prey at some point to the many options for a spiral into self-destruction that a city offers? Does he feel a proud sense of dignity in doing a honest day's work?
Vegetable pushcart man: I don't (yet) have the humanity to stop my vehicle and have a real conversation with you, so I just have to imagine all the above. But I salute you.
-- the daily pollution and dust
-- being completely at the mercy of the weather ; from hot sun to sudden showers. Imagine trundling your way home maybe 5 kilometers away in one of Bangalore's thunderstorms in roads running full of water with your business day washed out.
-- reducing business as the big shops like Reliance undercut everyone else
-- negotiating Bangalore's traffic and intersections where to the man in the CAR the pedestrians and pushcarts are irritants to be honked angrily out of the way as they interrupt the smooth flow of traffic.
Despite all these obstacles, the pushcart man endures. Why does he do it? Does he go home to a loving family that makes it all worth it for him? Does he feel he has no choice? Or does drink do the trick? Where does he draw the strength from, to continue his useful but uneviable role? Does he fall prey at some point to the many options for a spiral into self-destruction that a city offers? Does he feel a proud sense of dignity in doing a honest day's work?
Vegetable pushcart man: I don't (yet) have the humanity to stop my vehicle and have a real conversation with you, so I just have to imagine all the above. But I salute you.
Tuesday, February 09, 2010
Notes on "3 Idiots"
I saw it today, long after everyone else. (Impusively went to it Everest near our apartment ; was passing by at 9:20 pm and saw that they had a show at 9:30pm! I and Siddhu have been planning to go together sometime and he was genuinely shocked that I ditched him. I'll have to make it up).
Too long and loosely edited. Maybe I've just seen too many good movies but I get impatient easily at the movies.
Definitely didn't live up to the hype and good reviews. But was quite nice.
Stuck too much to stereotypes with Chatur Ramalingam and Suhas. Would have been interesting to make Chatur in particular much more serious and accomplished (that's what successful Indians in the US tend to be like) rather than an easy-to-dislike clown.
Nicely made its points about the education system including using old legends (urban or otherwise) like the NASA pen. We should have had this movie made 20 years ago, and maybe it would have saved me :-(. Delivery scene was far too contrived.
Scene where Farhan convinces his father was genuinely moving.
Gorgeous Ladakh scene at end. We don't need no Switzerland!
Would have made the movie lot more cool if they'd situated it in IIT like in the book. Campus they used looked very nice.
Kareena was weak in places and looked overawed at the star cast she was competing with.
Handling of Raju's parents was pretty good.
Song sequences were mostly a pain.
How do Aamir and Madhavan manage to look reasonably realistic as 20somethings ?!
After all the controversy with Chetan Bhagat ; I felt that while the movie was irrevocably situated in the ideas of the book, there was a huge amount of original stuff overall. Which doesn't say much I guess !
And they had some truly atrocious product placements. Shame on you Vidhu Vinod Chopra
Friday, January 29, 2010
Quote from "Catcher in the Rye"
J.D. Salinger also passed away yesterday. Here are two quotes from Catcher in the Rye:
"She was a pain in the ass but she was very good-looking" (from my memory)
"Anyway, I keep picturing all these little kids playing some game in this big field of rye and all. Thousands of little kids, and nobody's around - nobody big, I mean - except me. And I'm standing on the edge of some crazy cliff. What I have to do, I have to catch everybody if they start to go over the cliff - I mean if they're running and they don't look where they're going I have to come out from somewhere and catch them. That's all I do all day. I'd just be the catcher in the rye and all. I know it's crazy, but that's the only thing I'd really like to be."
More nice quotes: http://www.quotegarden.com/bk-cr.html
"She was a pain in the ass but she was very good-looking" (from my memory)
"Anyway, I keep picturing all these little kids playing some game in this big field of rye and all. Thousands of little kids, and nobody's around - nobody big, I mean - except me. And I'm standing on the edge of some crazy cliff. What I have to do, I have to catch everybody if they start to go over the cliff - I mean if they're running and they don't look where they're going I have to come out from somewhere and catch them. That's all I do all day. I'd just be the catcher in the rye and all. I know it's crazy, but that's the only thing I'd really like to be."
More nice quotes: http://www.quotegarden.com/bk-cr.html
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