My original post was about clouds and gliding. Should choose subject heading
more carefully.
These roll clouds occur more frequently than we realise.
John.
----- Original Message -----
From: Nick Gilbert
To: Discussion of issues relating to Soaring in Australia.
Sent: Wednesday, December 05, 2007 7:40 AM
Subject: Re: [Aus-soaring] Climate change.
I saw the word 'Cloud' in that one - we must be getting closer to talking
about Gliding again.
On Dec 5, 2007 1:29 AM, Mike Cleaver < [EMAIL PROTECTED]> wrote:
At 02:35 5/12/2007, you wrote:
> > There is "Climate Change", there always has been "Climate Change".
> > there was an Ice Age and the earth is going through a warming cycle
> > that has been going on since the last Ice Age. (Geoff, as
> recently as 1982 scientists thought we were heading for a new ice
> age caused by global cooling!)
>
>..... and the Earth continues to warm up (by insolation)...
>
>..... until it is hit by a big meteor which throws dirt into the air
blocking
>insolation and causing cooling (as in the last ice age). This wipes out
>many species.
Not that simple, even for a neonatologist. But there is one simple
concept nobody has raised here yet (or in the popular science
debates). That was the old paradigm.
Left to its own devices, the earth stays in rough balance by
radiating out the energy it receives. However, (1) it takes time to
achieve equlibrium; (2) the rate of radiation is less if there is
more cloud or more greenhouse gases to trap the heat by re-reflecting
it back to earth; (3) the rate of sunlight (energy) getting in
depends on the amount of cloud reflecting it back and the amount of
particulates stopping the sunlight getting to the surface and heating
the atmosphere.
HOWEVER, this assumes that no extra heat (energy) is released at the
surface. It is patently obvious that humans are now using energy at
such a rate as to affect the overall balance, and all energy
eventually defaults to heat - hence the earth's surface warms as the
waste product energy accumulates until it can be re-radiated to space
as long-wave radiation. Unlike other historical events, we cannot
tell yet if that effect is self-correcting.
The only way to radiate more energy (as a very rough approximation to
a black-body radiator) is to radiate it from a hotter source - hence
the planet MUST warm up if it is to radiate the excess energy being
generated at the surface.
If we suspect that this is an undesirable situation, we must STOP
RELEASING SO MUCH ENERGY. Ideally we will do this by being more
efficient and not wasting it, but the fact remains that in the end it
will raise the temperature ON AVERAGE. This is where Australia, as a
amall buttechnologically smart country, can help significantly BY
REDUCING WASTING ENERGY AND MAKING THE TECHNOLOGY AVAILABLE TO ALL.
In the long term, we must also reduce the global human population if
we are to reduce the number of sources of waste. Risk managers
consider number of fatalities against frequency to decide if a risk
is unacceptable - a single cause killing 1000 people at the same time
is not tolerable more than once in about 10 years. By extrapolation,
killing 5 billion people once in 5 billion years is also intolerable
- so half the planet's population being killed by a nearby star going
supernova once in the current age of the universe is intolerable. The
only factor we have any control over (apart from rewriting what
probability we accept) is to reduce the global population! (not in
the way one loony candidate party at the recent election has
proposed, either - by a solution akin to myxo or calici virus for
rabbit control, or relying on war and famine as we did in past generations).
The problem goes deeper than just greenhouse gas emissions - it is
ENERGY USAGE at a rate beyond our capacity to maintain the
environment in a range where we KNOW FOR SURE that we can survive it,
and which probably takes us outside the range of geological history
caused by variations in solar output in any time-scale we can
reliably infer from the up-front evidence.
CO2 is only a minor part of the overall equation, but it is the
political flavour of the year.
Wombat
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