Its very true that the argument has weakened. Note "weakened" doesn't mean "very weak", just "weaker than it was previously". You seem to be reading "weakened", as "destroyed the argument". That's not what the word means, or what I mean by using it.
First of all, more years in recent years have been records or in the top ten of hot years then at any other time in the last 100 years.
Almost meaningless. Most of the coldest years where in or around the 70s, does that mean that the world was about to enter in to a decisive cooling trend starting at that point? Apparently not. Temperatures are variable, within a day, within a year, within a decade, a century, a thousand years, and a million. Do I think that temperatures are warming now and that human emission of CO2 contributes to this? Yes, that's what the best evidence available suggest, but its not reasonable to say that the combination of this adjustment against the perceived trend doesn't weaken the evidence, the debate is only about how much, you might argue it trivially weakens it. I'd say its more than trivial. I'm not saying it destroys the argument or even close.
Secondly, 1934 was a hot year for the US, not necessarily the globe.
Yes the revision only covers the US, but the US had more readings to rely on than most of the globe, and weaknesses in the recording, organizing, and analyzing the US data also point to the possibility of weaknesses in other areas. There are reasons even to think some of the current US data is distorted or unreliable. (See norcalblogs.com and norcalblogs.com for a couple of examples, I could show a bunch of other ones if you really wanted me to)
Also there is concern that in many cases the trend in temperatures only becomes an upward one after upward adjustments have been made. Now there may be very good reasons to make those upward adjustments but the details and methodology behind the adjustments has not been made public so it can't be independently analyzed. Also many of the well known factors that would require adjustments, such as the urban heat island effect would suggest that downward adjustments should be made.
Thirdly, if you understand the theory behind global warming, you know that GW is caused by an increase of CO2 in the atmosphere. That didn't start in the last ten years or even in the 1930s. In fact, CO2 levels began to rise in the mid 19th century and were exceeding historical norms by the beginning of the 20th century. Therefore its not surprising that the 1930s or even the 1920s were starting to heat up.
But a lot more CO2 was emitted in 70s which where notably cooler than either the 30s or today. Also while records going back in to the 1800s are less reliable apparently we where warming before CO2 emissions where high enough to be a major factor. None of which is serious evidence for the argument that current CO2 emissions aren't causing a warming effect, only that the issue is complex and not a simple cut and dried "Inconvenient Truth". |
