WORLD
CLIMATE REPORT on: A Sea Surface Story
22 May 2008
OCEANCLIMATE
and related websites (see: Bottom Box) are looking for explanation why
global temperatures had run into a significant cooling for three decades,
starting in winter 1939/40 and being back to pre-WWII level only in the
1990s. (Details: Here).
Now
WORLD CLIMATE REPORT discusses a recent work by Hobson et al.
with the title “Ocean surface warming: The North Atlantic remains within
the envelope of previous recorded conditions”, concluding that “the
real world is not cooperating with expectations from predictions from
numerical climate models”.
According
Hobson et al: “The North Atlantic has undergone a net warming since
1976, and this recent warming parallels similar warming from 1910 to 1945.
Between these two recent warming eras the North Atlantic cooled by 1°C.”,
as indicated in the figure, which shows the mean latitudinal position of
the isotherms over varying time intervals based on data availability
thresholds.
Figure:
The mean latitudinal position north for the 12°C (black, from 1911
to 2005), 15°C (blue, from 1856 to 2005) and 18°C (red, from 1876 to
2005) isotherms. The length of timescale varies because of variations in
data availability.
WORLD
CLIMATE REPORT comments this as follows: Guess what year had the most
northerly extent of the isotherms – 1932!!! The second highest ranking
year was …. 1898! The remaining years ranked third to tenth were 2005,
1952, 1998, 2001, 1939, 1899, 1936, and 2003. These results, along with
others, led the team to conclude “We have shown that the current ‘warm
era conditions’ do not eclipse prior ‘warm’ conditions during the
instrumental record.” Furthermore, they write “In short, our analyses
suggest in recent years the position of summer isotherms in the North
Atlantic has not moved markedly beyond the window of previous values.”
OCEANCLIMATE
welcomes the clear sign that the scientific community is paying more and
more attention to the role of the oceans within the climate system. This
may pave the way to present also the reasons for the global cooling from
1940- ca. 1980 one day, and to acknowledge that climate
is - properly understood –
the blueprint of the oceans and seas.
Hobson, V.J., C.R. McMahon, A. Richardson, G.C. Hays. 2008. Ocean
surface warming: The North Atlantic remains within the envelope of
previous recorded conditions. Deep-Sea Research, 55,
155–162.