Hot Times in the City?

Climate Central has an interactive feature at the Huffington Post allowing Americans to determine "How Hot Will Summer Be In Your City In 2100?"

Here is how Climate Central came up with their apocalyptic summer heat projections for the end of this century:

Summer high temperatures (average of daily maximum temperatures for June, July, and August) were calculated for 1,001 U.S. cities with 1986-2005 data from PRISM Climate Group, Oregon State University. The projected summer high temperatures were calculated for these cities for the period 2081-2099, based on the RCP8.5 emissions scenario (and the other scenarios in a subsequent analysis), which is the high emissions scenario used in the IPCC's 5th Assessment Report. This is essentially a continuation of our current emissions trends through the end of the century.

According to Climate Central, "warming in coastal San Diego will make it feel like Lexington, Ky., – and represents more than a 6°F temperature increase."  Well, that is fascinating.  Here are the summer high temperatures (average of daily maximum temperatures for June, July, and August) in the San Diego area using data from the NOAA National Weather Service database.

These results are inconvenient for the alarmists.  Since 1970, there has been a highly statistically significant declining – not increasing – trend in summer high temperatures for San Diego.  And remember, according to the National Climate Assessment, we should see the most pronounced increase – not decrease – in temperatures since 1970.  Yet, somehow, summer high temperatures in San Diego will increase by more than 6°F by the late 21st century.

We could try using the NOAA National Climatic Data Center database for San Diego's maximum temperatures during the summer, but there seems to be a problem.

That's hot.  An average maximum summertime temperature of 224°F!  And look at that warming between 1939 and 1940.  That there is some serious greenhouse gas forcing, all concentrated on a single year in southern California.  Still, there is some good news for San Diego residents.  According to the NOAA-NCDC database, these blistering summer temperatures have been declining since 1980, and it is looks like the trend might dip below the boiling point of water sometime in the next few decades.

What about this prediction for Sin City?

In some cases, summers will warm so dramatically that their best comparison is to cities in the Middle East. Take Las Vegas, for example. Summer highs there are projected to average a scorching 111°F, which is what summer temperatures are like today in Riyadh, Saudi Arabia.

Right. And here are the summer highs since records begin in 1937 for the Las Vegas area.

That's not convenient, either.  There has been absolutely no significant trend in summer high temperatures for the Las Vegas area since the start of the climate record.  Indeed, the correlation is actually negative.  And no significant trend since 1970 either, or since 1980, 1990, or 2000.  Looks like not only does Vegas not have the oil resources of Riyadh, Saudi Arabia, but it won't have the climate, either.

How about this prediction?

By the end of the century, assuming the current emissions trends, Boston's average summer high temperatures will be more than 10°F hotter than they are now, making it feel as balmy as North Miami Beach is today.

Uh-huh.  And here are Boston's summer high temperatures since 1970.

That would be no significant trend since 1970.  Again, the correlation is actually negative, not positive.

We could play this game all day and night, going through all the 1,001 U.S. cities that Climate Central did and comparing the predictions to historical trends, but the point has been made.  There seem to be some major problems with the coming summer heat apocalypse Climate Central is projecting.