UHI Proves Global Warming!

By Paul Homewood


It’s summer time in the Northern Hemisphere, and it’s hot in places, but according to  Jason Samenow of the Washington Post, you must blame it global warming!

Reposted from the NZ Herald:


From the normally mild summer climes of Ireland, Scotland and Canada to the scorching Middle East, numerous locations in the Northern Hemisphere have witnessed their hottest weather ever recorded over the past week.

Large areas of heat pressure or heat domes scattered around the hemisphere led to the sweltering temperatures.

No single record, in isolation, can be attributed to global warming. But collectively, these heat records are consistent with the kind of extremes we expect to see increase in a warming world.

Let’s take a tour around the world of the recent hot-weather milestones.

North America

A massive and intense heat dome has consumed the eastern two-thirds of the United States and southeast Canada since late last week. It’s not only been hot but also exceptionally humid. Here are some of the notable all-time records set:

• Denver tied its all-time high-temperature record of 40.5 Celsius on Thursday.

• Mount Washington, New Hampshire, tied its all-time warmest low temperature of 15.5C on Monday.

• Burlington, Vermont, set its all-time warmest low temperature ever recorded of 26.6C on Monday.

• Montreal recorded its highest temperature in recorded history, dating back 147 years, of 36.6C on Monday. The city also posted its most extreme midnight combination of heat and humidity.

• Ottawa posted its most extreme combination of heat and humidity on Sunday.


Excessive heat torched the British Isles late last week. The stifling heat caused roads and roofs to buckle, the Weather Channel reported, and resulted in multiple record highs:

• Scotland provisionally set its hottest temperature on record. The UK Met Office reported Motherwell, about 20km southeast of Glasgow, hit 33.2C on Thursday, passing the previous record set in August 2003 at Greycrook. Additionally, Glasgow had its hottest day on record, hitting 31.9.

• In Ireland, on Thursday, Shannon hit 32C, its record.

• In Northern Ireland, Belfast hit 29.5C on Thursday, its record, and Castlederg hit 30.1C on Friday, its record


A large dome of high pressure, or heat dome, has persistently sat on top of Eurasia over the past week, resulting in some extraordinarily hot weather:

• In Tbilisi, Georgia, on Wednesday, the capital city soared to 40.5C, its all-time record.

• In Yerevan, Armenia, on Monday, the capital city soared to 42C, a record high for July and tying its record for any month.


So how do his claims stack up?

1) Denver

You will note that Samenow likes to quote big city sites, which are heavily affected by UHI. The record of 105F was registered at Denver International Airport, according to NWS.

Yet the all-time State record temperatures for Colorado were set in 1933 and 1954, long before Denver International Airport was opened in 1995.



In fact, if we check all the US State records, we find that the vast majority were set in the 1930s. Only two occur this century, S Carolina and S Dakota, and the latter only ties 1936 anyway.








It is extremely dishonest to use heavily UHI affected sites to claim temperatures are increasing because of global warming.

2) Montreal

For Montreal, read Denver, except the temperature reading was in the city itself, rather than the airport, which would make UHI worse still.

As with the US, nearly all of Canada’s all time state records occurred in the 1930s.

There is no coincidence about this. The infamous heatwaves of the dustbowl years were not simply localised events over a couple of summers, as is sometimes suggested. They affected most of North America throughout the decade.


Samenow talks dramatically about “heatdomes”, but these are simply areas of high pressure. As Environment Canada explained in a previous heatwave in 2011:

The heat dome phenomenon happens every few summers.”


And if he wants to blame single weather events on global warming, he might like to explain why Montreal suffered its coldest February in history – just three years ago.


UK & Ireland

As we know, that “Scottish record temperature claim” has had to be withdrawn, much to the embarrassment of alarmists.

In England, the CET series showed last month as only the 10th warmest June, with the hottest occurring as long ago as 1846.

The highest temperature in N Ireland was 30.1C, well below the record of 30.8C set in 1976 and 1983.

As for Ireland, Shannon International Airport may have set a record of 32C, confirmed by the Ireland Met Office as the  highest temperature anywhere in the country last month. But this was also well below the all-time record at Kilkenny in 1887, not to mention the 20thC record of 32.5C in 1976.





Samenow also quotes records at a couple of places in Asia, but both Tblisi and Yerevan, which he refers to, have both expanded massively in recent decades, both in terms of population and infrastructure.

Yerevan, for instance, has an estimated population of 1.1m, five times the size in 1939. The temperature is measured slap bang in the middle of an extremely built up city.





Tblisi too has grown in leaps and bounds, with population rising from 500K in 1939 to an estimated 1.5m now.

Hot Weather

Nobody would deny that there has been a lot of hot weather around in the UK, US and doubtless other places lately.

But they are certainly not unprecedented, and temperatures have been consistently well below other notoriously hot summers in the past.

To pretend that city and airport sites, where UHI artificially raises temperatures significantly, are representative of some sort of new climate is junk science, which meteorologists like Jason Samenow should be ashamed of peddling.



July 7, 2018 at 09:15AM

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