You’re confusing climate and weather. Average temperatures have remained about the same, average maximum temperatures have remained about the same, average minimum temperatures have remained about the same. The absolute lowest temperature recorded was recorded in 99.
Incidentally, CO2 should show the strongest effects on daily minimums, not daily maximums, owing to the mechanisms of its forcing. (Something which turns up in temperature records throughout the rest of the nation, incidentally.)
Your criticism would be correct if addressed to Thomas’s post. The argument there was of the form “If X, then Y” … with the implication of not-Y and therefore not-X. My post was just establishing that Y.
Not necessarily. Can’t find the paper now, but a team which analyzed nationwide temperature measurement stations found that stations with good placement (that is, not placed right next to an air conditioning unit, or next to a runway, or somewhere else where external heat sources messed with the measurements) experienced considerably increases in daily minimums, but only minute differences in daily maximums; a trend which produces a higher average relative to the maximum than might be expected.
Typical estimates of current global warming rate are on the order of 0.015 K per year.
Least-squares fitting of a straight line to the monthly average temperatures in Death Valley from the site above, after subtracting off month-by-month averages to avoid getting confused by ordinary seasonal variation, gives a rate of increase of 0.027 degrees F per year, or … 0.015 K per year.
So it looks to me as if the Death Valley figures fit perfectly with the consensus view of global warming. In particular, it is not true that “average temperatures have remained about the same” unless you count the current consensus view of global warming as saying that global average temperatures have remained about the same.
Similar fits for the other statistics in that table, in order of appearance there, all in K/year: monthly lowest temp +0.010, monthly highest temp +0.044, monthly highest daily min temp −0.020 (!), monthly lowest daily max temp +0.018, monthly avg daily min temp +0.0004, monthly avg daily max temp +0.029.
Could you say more in support of your claim that CO2 should show its strongest effect on daily minima rather than maxima? I had a quick look with Google and all I found was some anti-AGW website saying that increases in daily minima are not an indication of global warming because they’re all to do with urban heat islands.
(Fair enough if the answer is that you don’t feel like paying the karma tax for replying to something downstream of a severely downvoted comment.)
Unfortunately it appears the field has undergone a lot of changes in the past five years. When I last researched the matter, it was considered good evidence -for- AGW (albeit evidence for a “lukewarmist” position), and attention had just been focused to it by the products of a skeptical initiative to document the conditions of temperature stations and a subsequent paper which attempted to de-bias the UHI effect out of the temperature record—given that the de-bias attempt is what -produced- the attention on daily minima (which it found to have increased substantially, with only a statistically insignificant increase in daily maxima), I’m slightly suspicious of any claim that an increase in daily minima has to do with the UHI effect. (Namely, correcting for the UHI -produces- a stronger trend in daily minima compared to daily maxima or averages; if the UHI were -responsible- for this trend, we’d expect the reverse.)
But I have no idea what happened to the original papers, which were substantially better than what I can find today.
You’re confusing climate and weather. Average temperatures have remained about the same, average maximum temperatures have remained about the same, average minimum temperatures have remained about the same. The absolute lowest temperature recorded was recorded in 99.
Incidentally, CO2 should show the strongest effects on daily minimums, not daily maximums, owing to the mechanisms of its forcing. (Something which turns up in temperature records throughout the rest of the nation, incidentally.)
Your criticism would be correct if addressed to Thomas’s post. The argument there was of the form “If X, then Y” … with the implication of not-Y and therefore not-X. My post was just establishing that Y.
Your post is establishing Z, actually, a largely unrelated temperature phenomenon—maximum temperature. Hence my second paragraph.
Average temperature is relevant in this context, as average temp goes up we should expect the maximum to go up as well.
Not necessarily. Can’t find the paper now, but a team which analyzed nationwide temperature measurement stations found that stations with good placement (that is, not placed right next to an air conditioning unit, or next to a runway, or somewhere else where external heat sources messed with the measurements) experienced considerably increases in daily minimums, but only minute differences in daily maximums; a trend which produces a higher average relative to the maximum than might be expected.
Typical estimates of current global warming rate are on the order of 0.015 K per year.
Least-squares fitting of a straight line to the monthly average temperatures in Death Valley from the site above, after subtracting off month-by-month averages to avoid getting confused by ordinary seasonal variation, gives a rate of increase of 0.027 degrees F per year, or … 0.015 K per year.
So it looks to me as if the Death Valley figures fit perfectly with the consensus view of global warming. In particular, it is not true that “average temperatures have remained about the same” unless you count the current consensus view of global warming as saying that global average temperatures have remained about the same.
Similar fits for the other statistics in that table, in order of appearance there, all in K/year: monthly lowest temp +0.010, monthly highest temp +0.044, monthly highest daily min temp −0.020 (!), monthly lowest daily max temp +0.018, monthly avg daily min temp +0.0004, monthly avg daily max temp +0.029.
Could you say more in support of your claim that CO2 should show its strongest effect on daily minima rather than maxima? I had a quick look with Google and all I found was some anti-AGW website saying that increases in daily minima are not an indication of global warming because they’re all to do with urban heat islands.
(Fair enough if the answer is that you don’t feel like paying the karma tax for replying to something downstream of a severely downvoted comment.)
The number of data points in that sample, at least, probably don’t support that degree of precision.
As for the minima versus maxima claim, I can only point you in the right direction; Google “declining DTR”.
Unfortunately the science is a lot more all-over-the-place than I had anticipated; the NOAA appears to agree, more or less, with the skeptical claim there (see http://www.nws.noaa.gov/ost/climate/STIP/FY11CTBSeminars/lzhou_052511.htm ), whereas the IPCC appears to disagree (see http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=422 ) . Then you have people making claims at odds with both of them (see http://www.co2science.org/articles/V3/N33/C3.php )
Unfortunately it appears the field has undergone a lot of changes in the past five years. When I last researched the matter, it was considered good evidence -for- AGW (albeit evidence for a “lukewarmist” position), and attention had just been focused to it by the products of a skeptical initiative to document the conditions of temperature stations and a subsequent paper which attempted to de-bias the UHI effect out of the temperature record—given that the de-bias attempt is what -produced- the attention on daily minima (which it found to have increased substantially, with only a statistically insignificant increase in daily maxima), I’m slightly suspicious of any claim that an increase in daily minima has to do with the UHI effect. (Namely, correcting for the UHI -produces- a stronger trend in daily minima compared to daily maxima or averages; if the UHI were -responsible- for this trend, we’d expect the reverse.)
But I have no idea what happened to the original papers, which were substantially better than what I can find today.