I've come across this, written by an American called Steve Mann. I just want to focus on two of his points, which I think do not help the global warming arguments.
There are factors concerning global climate in which climatologists have high confidence.
4) The global climate has warmed nearly 0.7°C (+/- 0.2°C) in the last 100 years. NASA's Goddard Institute for Space Studies (GISS) has collected data since about 1880 and the UK's Hadley Center Climate Research Unit since 1850. Their results have substantiated each other.
(9) With the exception of a couple of downswings, global sea surface temperatures have been rising for about 100 years.
First, I do think there is global warming, so don't think I'm one of those skeptical folk!
I have to say that data from 100 years ago - while important in not contradicting the thesis - is likely to be more localised, and less accurate than modern data collection. To make a statement about "global" sea temperatures, taking data from 1908, does make me shudder. What does "global" mean in this context? How many temperature readings, over what part of the globe, and over what periods of time, at what months, days, hours of the day, constituted these early readings, and what sampling error can we assume given the limitations of measurement at the time? And how can we be sure than the measurements taken were comparative to modern readings. Bold statements like this seem fine, but are so generalised as not to rate "high confidence" statistically.
What I would prefer to see is an argument which stated that the samples of data which we have from 1908 support the thesis of global warming, and do not contradict it, and this is further confirmed by readings taken from a more modern period, perhaps post-war (I assume global sea temperatures were not much on the agenda during 1940-1945 - unless the Japanese kept their own records for their part of the globe!!!).
Generalising from local measurements to global ones is fraught at the best of times, and when possible differences in measurement at different times are taken into account (1908 compared to 2008), it is setting up a target ready for the skeptics to take easy pot shots at.
There are factors concerning global climate in which climatologists have high confidence.
4) The global climate has warmed nearly 0.7°C (+/- 0.2°C) in the last 100 years. NASA's Goddard Institute for Space Studies (GISS) has collected data since about 1880 and the UK's Hadley Center Climate Research Unit since 1850. Their results have substantiated each other.
(9) With the exception of a couple of downswings, global sea surface temperatures have been rising for about 100 years.
First, I do think there is global warming, so don't think I'm one of those skeptical folk!
I have to say that data from 100 years ago - while important in not contradicting the thesis - is likely to be more localised, and less accurate than modern data collection. To make a statement about "global" sea temperatures, taking data from 1908, does make me shudder. What does "global" mean in this context? How many temperature readings, over what part of the globe, and over what periods of time, at what months, days, hours of the day, constituted these early readings, and what sampling error can we assume given the limitations of measurement at the time? And how can we be sure than the measurements taken were comparative to modern readings. Bold statements like this seem fine, but are so generalised as not to rate "high confidence" statistically.
What I would prefer to see is an argument which stated that the samples of data which we have from 1908 support the thesis of global warming, and do not contradict it, and this is further confirmed by readings taken from a more modern period, perhaps post-war (I assume global sea temperatures were not much on the agenda during 1940-1945 - unless the Japanese kept their own records for their part of the globe!!!).
Generalising from local measurements to global ones is fraught at the best of times, and when possible differences in measurement at different times are taken into account (1908 compared to 2008), it is setting up a target ready for the skeptics to take easy pot shots at.
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