Influence of Urban Heating on the Global Temperature Land Average using Rural Sites Identified from MODIS Classifications
Wickham C1 , Rohde R2 , Muller RA3,4 *, Wurtele J3,4 , Curry J5 , Groom D3 , Jacobsen R3,4 , Perlmutter S3,4 , Rosenfeld A3 and Mosher S6
The effect of urban heating on estimates of global average land surface temperature is studied by applying an urban-rural classification based on MODIS satellite data to the Berkeley Earth temperature dataset compilation of 36,869 sites from 15 different publicly available sources
We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.10 ± 0.24°C/100yr (2σ error) in the Berkeley Earth global land temperature average. The confidence interval is consistent with a zero urban heating effect, and at most a small urban heating effect (less than 0.14°C/100yr, with 95% confidence) on the scale of the observed warming (1.9 ± 0.1°C/100 yr since 1950 in the land average from Figure 5A).
Everyone knows there is an urban heat island effect. This has been understood for a couple of centuries. The weather forecaster says every night “a few degrees cooler in outlying areas.” Many cities have had studies done showing five to ten degrees warming in town relative to truly rural areas. Even tiny towns like Barrow, AK have 2-3C UHI effects
So how did Mosher and Curry come to a conclusion so utterly daft?
They made the standard climate science mistake of doing a bunch of math on a problem they don’t understand. Barrow would certainly appear as a rural site in their methodology, yet Barrow has 2-3C UHI.
I routinely observe 5 degrees F warming just going from open space on my bicycle into an adjacent neighborhood. The presence of any asphalt, brick, heated houses and snow removal in the area has a marked effect on temperature. How could they not have an effect?
Over the past hundred years suburban sprawl and pavement has spread everywhere. This has had a marked effect on the surface temperature record, and has nothing to do with urban lights. There is no reason to expect that downtown areas would have changed much over the past century, because they were already paved over. It is the semi-rural areas which have expanded and been paved over. Curry and Mosher see UHI warming in supposedly rural sites, but don’t recognize it as UHI warming – because their methodology is flawed.
Garbage in/garbage out. Standard fare for peer-reviewed climate science. Next I will show you what actual UHI science looks like.
I did a survey of the ten oldest stations in New South Wales And Victoria, circled below. Three rural stations were not included because of obvious problems with the data, but none showed any warming.
MELBOURNE REGIONAL OFFICE ASN00086071 DENILIQUIN (WILKINSON ST) ASN00074128 BATHURST GAOL ASN00063004 SYDNEY (OBSERVATORY HILL) ASN00066062
CAPE OTWAY LIGHTHOUSE GSN ASN00090015BOURKE POST OFFICE ASN00048013 WAGGA WAGGA (KOORINGAL) ASN00072151FORBES (CAMP STREET) ASN00065016 INVERELL COMPARISON ASN00056017GUNNEDAH POOL ASN00055023
The two urban stations at Melbourne and Sydney both showed strong warming, and both have disastrously poor siting of their thermometers in the middle of large cities.
By contrast, all of the rural stations show a long term cooling trend, with some recent warming. (Note that there is no data for the most recent years with some of the rural stations.)
The only conclusion which can be derived from this is that Australia has not warmed long-term, and that BOM claims of record temperatures are due to UHI and/or data tampering.
For all GHCN stations in Australia, there is no net warming since 1880
Curry and Mosher tell us that there is no UHI and no warming due to data tampering. First rate comedy.