"Jim Webster" wrote in message
...

"Pete B" wrote in message
...

The weather and even more so, the financial worlds, are littered with
total
failed forecasts based on statistical predictions from the recent past.
What
statistics forecast the Stockmarket crashes just as the markets were,
unbeknown to even experts, peaking back in the late '90's? In the mid
1970's, climate statistics suggested a trend heading back downwards in
global temperature and the media hype was all about new ice ages. That
all
looks very silly now doesn't it? I have little faith in statistics as a
future forecasting tool, the climate will do what nature dictates
whatever
statistics may indicate about it.


Yes, I must confess that every so often, when someone lectures me on
future
trends, I look at the foreword to my AA Atlas of Great Britain (1967)
which
talks of the coming ice age

After reading that one adopts a properly detached view :-))


AIUI, the predictions of a forthcoming ice age were based not just on a
short-term temperature drop, but on the changing nature of the earth's orbit
around the sun. I was at school in the 1960s and early 1970s and remember
such things as writing a speculative essay on continental drift (not
confirmed until well into the 1970s) and also the "Ice Age" scare when the
Milankovitch theory was still being explored. During the same period we
were also speculating on whether Venus was an ocean planet or a desert
because there was no information - these were the days largely before robot
exploration of other planets.

Those less than a certain age (about 40 or so) may find it hard to
understand how little was known before the late 1960s compared to what is
known today.

There are some fairly obvious comments on the observations which started
this thread:

1) The CO2 level in the atmosphere is now getting on for twice the
undisturbed level. As temperature changes in the past have been correlated
with CO2 levels for periods of millions of years, it seems hard to believe
that our modification of the atmosphere is having no effect.

2) I believe the record warm year was associated with a large "El Nino"
event. These warm the whole globe by an amount larger than the currently
observed trend. In other words, 1998 may have been a "spike" sticking out
above the noise. It may need another large El Nino or a decade or two of
steady temperature rise before this record is broken.

3) There are other factors which may cause natural variations of a few
degrees on various timescales. Should one of these be now causing
temperatures to drop, this might mask a steady warming for some period of
time until there is a renewed, and possibly quite sharp, temperature rise.


But as has so rightly been said, you have to be so careful with statistics,
especially short period ones. 24 years of local weather records appear to
show a warming trend of about 0.25C since 1980. But superimposed on this is
annual variability of the order of 1.5C. Also, my records started (1980)
around the end of one of the coldest spells of recent times, so the apparent
"warming" trend could be due to irregular bunching of cold and warm years.

The blunt fact of the matter is that we currently have insufficient
information to say exactly what is happening with the climate beyond all
reasonable doubt. So we have conflicting stories about heat and drought or
about arctic Britain, depending on whose article you read. This gives
ammunition to the vested interests (on both sides) and allows the
politicians an excuse to do little but make token gestures.

The bad news is that by the time we *do* know beyond all reasonable doubt
what is happening, it may be too late...
--
- Yokel -
oo oo
OOO OOO
OO 0 OO
) ( I ) (
) ( /\ ) (
Yokel @ Ashurst New Forest
SU 336 107 17m a.s.l.

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