is global warming our fault; caused by carbon or is it just that the earth has been warming up ever since the ice age?

Modern day volcanoes, i.e. the last few thousand years seem to be responsible for noticable cooling effects on the climate, i.e. Mount Pinatoba, Tambora etc.  This is i assume is down to dust, ash and sulphur dioxide been spewed into the air and reflecting incoming solar radiation.

 Although it seems volcanism in earths geological history appear to be responsible for notable warming events, attributed to greenhouse gas emmisions.  I know the residence time of greenhouse gasses are usualy longer than ash, dust and sulphur aerosols, however continued eruptions i would imagine would keep a constant supply of sulphur in the atmosphere thus cooling the planet.

Please explain this contradiction.

Thanks

Mark

As the polar ice caps melt the sea levels are predicted to rise. My question is why? When you place an ice cube in a glass of water the water level rises, but if the ice cube is already there and then it melts the water level does not rise, due to the initial displacement of the water by the ice. Surely the same principle must be true of the ice caps. Why, therefore, are melting polar ice caps leading to a rise in sea levels?

 Glaciers flow across landscapes carrying boulders and debris e.t.c. Until recently I always assumed they travelled downhill, but I hear they can carry boulders uphill. How is this gravity defying feat possible?

Ian Jones, Solihull, UK

I've heard that most of the earth's energy comes from the sun (oil, wind, solar etc). Where does the rest of it come from?

If water could be pressurised, how low would the sea level be due to the pressurising weight of the overlying water?

If you look at a map, around Thera/Santorini there is a rough circle bounded by Crete & Rhodes to the South, with Thera itself near the centre, in the Cyclades. Is it possible that this area marks an enormous “supervolcano”? I know Santorini itself is proposed as the remains of a huge volcanic explosion, but I’ve only seen this applied to Santorini’s crater, not to a wider area.

After reading about the precession of the equinoxes and the change of the seasons over thousands of years, I was wondering if the equinoxes and solstice dates are actually getting earlier or later to compensate for this phenomena?  I've always known them to be on the 21st December and 21st June (with a bit of fluctuation), I also know the Gregorian calendar changed from the Julian calendar, was this because of this phenomena, please help.

Why 'on earth' do we see only one side of the moon ?