Convert value set with ON UPDATE CURRENT_TIMESTAMP to UTC - mysql

Question

In MySQL a field was created with ON UPDATE CURRENT_TIMESTAMP designation. This saves the record update date in the server's timezone. I want to convert this time to UTC time.
The server is hosted in an account that doesn't have access to the server administration or the MySQL administration so I can't set the timezone on the server or MySQL directly through command line interfaces or startup files or any other way. This includes the SET time_zone command or the my.cnf file.
I also found a suggestion to use ON UPDATE UTC_TIMESTAMP but found this gives a syntax error and is not supported in the documentation.
So what I am trying to do now is to find a select clause that converts the value saved by ON UPDATE CURRENT_TIMESTAMP, which is saved in the server's current timezone, and convert it to UTC time.
Ideally this clause would detect the server's timezone so the value is not hardcoded and works with whatever timezone the server is set to.

Answer 1

Since nobody answered this question here is the workaround I ended up using:
Since I access mySQl from php I used php to solve the problem by calculating the difference in seconds from server time to UTC then subtracting that amount in the SQL statement.
Here is the PHP function to calculate the difference in seconds from server time to utc:
function utcOffset() {
$serverTime = new DateTime('NOW');
return $serverTime->getOffset();
}
Here is how I built the SQL statement in PHP to select time in utc in seconds since 1-1-1970:
$sql .= "SELECT TIMESTAMPDIFF(SECOND, '1970-01-01', myServerTimeStampField)-".utcOffset()." AS timeInUTCSeconds FROM myTable";