Hello Gordon Keen,
Gordon Keen writes:
> Hi Martin
>
> If the climate is being changed by mankind's excessive use of
> hydrocarbons creating a "greenhouse" effect what caused the past climate
> changes when there was no human population?
An excellent question to which no one presently knows
the undisputed answer, but it is thought based on pretty good
evidence that the Earth's atmosphere used to be a lot different.
There was a lot more carbon dioxide and sulphur and less oxygen.
Actually, at one time, no oxygen at all.
Then one-celled plants began to live in the oceans and
that is the current theory on how we got oxygen.
Methane is another greenhouse gas that is many times
worse at trapping heat than carbon dioxide and it is found in
ice formations in some parts of the world. It is theorized that,
at one time, a huge amount of this stuff melted and released
methane in to the air in what some have called "the big belch"
That could have raised temperatures a whole lot, very fast.
> I read an article the other day which pointed out that the antarctic ice
> shelf which climate doommongers opined were shrinking had in fact grown
> over the past decade. ( raised eyebrow )
That's news to me but I am not saying it didn't happen.
> I'm not saying there is no climate change, I am just not convinced it is
> being caused by atmospheric carbon dioxide and may in fact be more to do
> with solar activity ( or the lack thereof ) that may be the guilty party
> and we are beating ourselves up over something which we have no control
> over.
That is quite possible but we do know for a fact that
carbon dioxide has almost doubled in the last 150 or maybe 175
years.
How do they know that? There is ice in mountainous
regions that has not melted for around ten-thousand years. It
contains air bubbles that were in the water when it last froze
and the CO2 level is fairly constant up until about 1800 or so
when we began burning coal on a huge scale in Europe and the
United States.
I think there are natural cycles and then we may be
hurrying things on a bit so we may get in trouble sooner, but
who knows for sure? I surely don't.
Astronomers say that our Sun is an average star and has
been putting out pretty much the same energy level for billions
of years. They also think it is middle-aged so it has about as
far to go as it has come. Of course it could wipe out all life
on Earth by getting just a little cooler or hotter or if our
orbit changed to bring us closer to the Sun or further away, but
it is more likely that climate changes here were caused by
atmospheric changes. It is pretty certain that an asteroid fell
to Earth in what is now North America and that impact raised
dust clouds that blotted out the Sun and did Heaven knows what
else, possibly killing off most of Earth's life but we don't
really know, obviously.
We may not know for sure if our use of petroleum is
changing climate, but the one thing we do know is that we will
run out of this stuff one day so that is the best argument for
figuring out other ways to power our lives while there is still
time.
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