Post by charmbrights on Jul 17, 2014 21:15:50 GMT
This was advertised as:
I watched as much of this programme as I could stomach. It was based on three doubtful premises.
1 The assumption that the computer models of climate and weather as currently used are accurate.
2 The assumption that because we observe two phenomena to occur that one must cause the other - and in the relationship that these two experts agree.
3 The assumption that "in the future as the world warms" for which the historical data is very limited.
1 The assumption that computer models of very complex systems are accurate is at best naïve and at worst stupid. Vide the weather forecasts even a few hours ahead, let alone years. Even the modelling of relatively simple systems is very difficult - for example in a vacuum fix two magnets on a flat surface - hang a steel ball above them and exactly between them. Move it a tiny distance away from its equilibrium position above them - it is impossible to predict over which magnet it will come to rest.
2 Post hoc ergo propter hoc (Latin: "after this, therefore because of this") is a logical fallacy (of the questionable cause variety) that states "Since event Y followed event X, event Y must have been caused by event X."
3 We have had a series of "ice ages" (cycles of glaciation with ice sheets advancing and retreating on 40,000 and 100,000 year time scales) and, in the UK, "little ice ages" (conventionally defined as a period extending from the sixteenth to the nineteenth centuries, or alternatively, from about 1350 to about 1850). Even in the USA weather records are not considered accurate before about 1995, though limited data is available from 1948 (source National Climatic Data Center).
Over the last few years, our weather in Britain has become more extreme.
Last winter was the wettest ever recorded, as deadly storms battered the country for weeks on end. But previous winters have seen bitter lows of -22, as Britain was plunged into a deep freeze.
What everyone wants to know now is: why is our weather getting more extreme, can we expect to see more of it in the future, and has it got anything to do with climate change?
In this episode of Horizon, physicist Dr Helen Czerski and meteorologist John Hammond make sense of Britain's recent extreme weather and discover that there is one thing that connects all our recent extreme winters - the jet stream, an invisible river of air that powers along 10 km above us. What's worrying is that recently it has been behaving rather strangely.
Scientists are now trying to understand what is behind these changes in the jet stream. Helen and John find out if extreme winters are something we may all have to get used to in the future.
Last winter was the wettest ever recorded, as deadly storms battered the country for weeks on end. But previous winters have seen bitter lows of -22, as Britain was plunged into a deep freeze.
What everyone wants to know now is: why is our weather getting more extreme, can we expect to see more of it in the future, and has it got anything to do with climate change?
In this episode of Horizon, physicist Dr Helen Czerski and meteorologist John Hammond make sense of Britain's recent extreme weather and discover that there is one thing that connects all our recent extreme winters - the jet stream, an invisible river of air that powers along 10 km above us. What's worrying is that recently it has been behaving rather strangely.
Scientists are now trying to understand what is behind these changes in the jet stream. Helen and John find out if extreme winters are something we may all have to get used to in the future.
I watched as much of this programme as I could stomach. It was based on three doubtful premises.
1 The assumption that the computer models of climate and weather as currently used are accurate.
2 The assumption that because we observe two phenomena to occur that one must cause the other - and in the relationship that these two experts agree.
3 The assumption that "in the future as the world warms" for which the historical data is very limited.
1 The assumption that computer models of very complex systems are accurate is at best naïve and at worst stupid. Vide the weather forecasts even a few hours ahead, let alone years. Even the modelling of relatively simple systems is very difficult - for example in a vacuum fix two magnets on a flat surface - hang a steel ball above them and exactly between them. Move it a tiny distance away from its equilibrium position above them - it is impossible to predict over which magnet it will come to rest.
2 Post hoc ergo propter hoc (Latin: "after this, therefore because of this") is a logical fallacy (of the questionable cause variety) that states "Since event Y followed event X, event Y must have been caused by event X."
3 We have had a series of "ice ages" (cycles of glaciation with ice sheets advancing and retreating on 40,000 and 100,000 year time scales) and, in the UK, "little ice ages" (conventionally defined as a period extending from the sixteenth to the nineteenth centuries, or alternatively, from about 1350 to about 1850). Even in the USA weather records are not considered accurate before about 1995, though limited data is available from 1948 (source National Climatic Data Center).
