does Glacier Ice tell us?
One strong line of evidence that it is comes from an
unlikely source – the vast ice sheets of Greenland
and Antarctica. As glacier ice is formed by compaction
of successive layers of snow, small bubbles of air become
trapped. When a sample of ice is drilled out, these
air bubbles can be dated quite accurately, and when
analysed, provide an archive of past atmospheric composition
– including the levels of CO2, CH4 and N2O. sets
the current situation in the context of ice-core data
that trace variations in the atmospheric concentrations
of these three gases over the past millennium.
Sun is the ultimate source of energy for the Earth's climate.
A planet such as the Earth will have a stable temperature
as long as there is a balance between the rate at which energy
comes in from the Sun and the rate at which it is returned
to space by the planet. If the two rates fail to match, the
planet will either warm up or cool down until a balance is
is no dispute about this central conclusion. Increasing the
atmospheric concentration of CO2, or any other greenhouse
gas, will force the global climate to warm up; it can be refered
to as ‘greenhouse forcing’. However, the weighty
tomes issued by the IPCC bear witness to the fact that ‘the
devil is in the detail’! In particular, there is still
major uncertainty about what is perhaps the most fundamental
question in the whole climate change debate: how much will
the Earth's temperature rise in response to a given amount
of greenhouse forcing?