Looking at my local
rural temperature records for the past 100 years (and not the databases of NOAA, GISS, etc), there is no hockey - stick effect.
Not exact matches
On the other hand Plimer cited evidence that
rural centres used to
record long - term
temperatures, mostly tended downwards.
These include that the land, borehole and marine
records substantially agree; and the fact that there is little difference between the long - term (1880 to 1998)
rural (0.70 °C / century) and full set of station
temperature trends (actually less at 0.65 °C / century).
On the other hand Plimer cited evidence that
rural centres used to
record long - term
temperatures, mostly tended downwards.
Back in ’88 there was still quite a debate about whether the world was in fact warming or whether the
temperature record had been contaminated by the urban heat island effect of cities springing up around former
rural weather stations.
This is one of the main challenges with the urban heat island problem — it is harder to keep enough staff to maintain a continuous
temperature record at an isolated
rural location for a century (or longer) than in the heart of a thriving metropolis.
If you only use linear trends for analysing the
temperature record for Valentia Observatory, you might mistakenly conclude, «it shows a «warming trend», and it's
rural, so even the
rural stations show «unusual global warming»».
Most of the
rural cities in my state show no warming at all since 1890 - 1895 when the
records began but this is but one area and maybe it has some special properties that protect it, or shield it, from this assumed increase in accumulated global energy (therefore a raising of
temperature) but in physics I learned that is not possible over a century of time even in a system even as large as the entire Earth.
In other words, it is one of our only
rural station
records that we can use for studying long - term
temperature trends.
For the rest of the world, the Historical Climatology Network datasets didn't actually have enough
rural stations with sufficiently long
records to estimate global
temperature trends.
The most likely explanation being that the land based thermometer
record has become inaccurate due to station drop out, particularly high latitude drop out, a biasing towards airport stations, poor station siting and a failure to properly allow for UHI which is having an ever increasing impact upon post 1960s
temperatures because of not simply an increase in urbanisation but also the drop out of
rural stations and the ever increasing percentage of airport stations and airports have so greatly changed during the 1970s and 1980s.
There does seem to be enough
rural stations with long
records to be reasonably confident about the U.S.
temperature trends for the 20th century, but not for the rest of the world.
The most likely explanation being that teh land based thermometer
record has become inaccurate due to station drop out, particularly high latitude drop out, a biasing towards airport stations, poor station siting and a failure to properly allow for UHI which is having an ever increasing impact upon post 1960s
temperatures because of not simply an increase in urbanisation but also the drop out of
rural stations and the ever increasing percentage of airport stations and airports have so greatly changed during the 1970s and 1980s.
You don't seem to understand that the
temperature records are calibrated to correct for urban effects, and the very close match between DFW and a nearby
rural station shows that this is accurately done.
The stations locations are surfacing the property price wave, where the conurbation is spreading, the stations are pushed fastest, always
recording the rapid
rural to urban
temperature profile.
There are some stable
rural temperature stations with long term
records of zero warming in the industrial era.
Seven
rural temps in western europe with long term
temperature records show zero warming.
Some of the
temperature increases shown by Dr Jones in fact are caused by
temperature recording stations that were once in
rural locations on the outskirts of cities now being affected by the Urban Heat Island effect as urban development surrounded the weather stations.
The moral of the story is, find any
rural station with an odd
temperature record and I will show you nearby urban stations with a head - scratching adjustment.
They effectively replace the
temperature record of all urban stations with the distance - weighted average of nearby
rural stations.
Although the global network nominally contains
temperature records for a large number of
rural stations, most of these
records are quite short, or are missing large periods of data.
How about
rural good stations with MMTS having substantially lower trend that good
rural CRS (if I am not wrong, the MMTSs do not have any TOBS issues, since they automatically
record the highest and lowest
temperature for a given day?)?
According to the U.S. Environmental Protection Agency, urban areas regularly
record air
temperatures as much as 6 ° Celsius (10 ° Fahrenheit) hotter than the surrounding suburban and
rural areas.
As the trend in the US
rural stations, which at least until very recently employed these min / max stations, has been from early evening observation (5 pm or 7 pm in most of the sources I've found) to early morning observation (usually 7 am), this has been presumed to put an artificial cooling bias into the
temperature record, so a net positive, and increasing as more stations have been converted, correction has been added to the raw data.
One issue of the
temperature data related to Urban / suburban /
rural is that, given no microsite bias, all three
temperature records are valid.
The fact that the raw data in long term
rural reporting stations always show a long term flat
temperature (or a decline) while the interpolated anomaly shows warming is going to tend to inform me that people are fudging the
records.
Temperature records from around the world — from weather stations in both urban and
rural areas, and from weather balloons and satellites — tell us the world is warming.
Over time, some weather stations that once
recorded temperatures in
rural areas have been surrounded by cities and suburbs.
I'm monitoring the monthly
temperature averages for the period of
record in the regions for each of the NWS Cooperative Climate Stations (
rural, forested and small town areas) and creating average monthly
temperature plots because I think someone needs to be doing this.
There have been a number of studies suggesting that ground - based data is severely compromised by urban heat island effects, inappropriate placement of monitors that increase
recorded temperatures over what they would have been if the instruments had been properly cited, and the drop - out of a large number of
rural stations in the 1970s.