Monday, April 15, 2013

Bob G Returns to Normalcy

Bob Grumbine has a couple of posts( #1 and #2) asking when was the climate normal.  His conclusion is

  • Climate was 'normal' only between 1936-1977
  • Every year 1987-present has been warmer than any year before that
  • 1976 was warmer than any year before 1926
  • 1978 (next coldest year of the recent run) was warmer than any year before 1940
  • 1937 is much warmer than all the preceding years.
In #2, Bob makes some important points about why this matters.  Further, those who insist that GISS needs to redefine its base period for anomalies (1951-1980) might take heed and GISS itself might want to shade a couple of years off. 


Anonymous said...

This is interesting.

By proclaiming 1936 part of normal, it is a declaration that the 'Dust Bowl' was part of normal climate - which it was, of course, but something to remember on what 'normal' climate includes.

GISS used to have a good chart ( that they don't offer anymore ) that looked like this:

Northern lats were abnormally cold from 1880 to 1920, abnormally warm from 1930 to 1960. Little time at all has been 'normal' poleward of 55 degrees.

Similarly, the IPCC produced this chart of precipitation which demonstrates the global variation over time. Climate has NEVER been normal.

One cannot turn the clock back to a previous period and not piss someone off because their region isn't hotter or colder, drier or wetter than average.


Anonymous said...

Climate has NEVER been normal.

Climate is not weather, it is the symplectic trajectory of weather. You're supposed to be familiar with these basic concepts before you post here, and if you aren't - then ask.

Thanks in advance.

EliRabett said...

Oklahoma never was and never will be normal

Gaz said...

Changing the base would attract a wave of ill-informed or dishonest accusations from the usual crowd of deniosaurs.

Not worth the trouble.

metzomagic said...

Willard Tony would just *love it* if you changed the baseline period to a later one because then the anomalies would be smaller. He'd get years of extra mileage at being not only wrong out of that :-)

Robert Grumbine said...

If GISS, et al., were to shift to my 'normal' period, then there'd be much whinage from the usual corners, as Gaz suggests. 1936-77 was much cooler than 1981-2010 (the should-be reference now, by usual NOAA + WMO practice+recommendation).

As usual, you shouldn't make too much out of the end years. It's 1937-1976 if I chose to round differently.

kt: I'm accustomed to hearing symplectic in connection with Hamiltonians. What is climate's Hamiltonian?

Anonymous said...

What is climate's Hamiltonian?

From afar, a very complicated transformation in a very complicated Hilbert space. If you look at any part of it very closely most likely you will have to revert to statistical mechanics, and then statistics. It's something you construct, compare with reality, and then construct again. It's not real, it's a model of reality. Mathematics is weird that way. It's both discrete and continuous but neither discrete nor continuous, oh ... forget it. Which came first, mathematics or physics?