Originally posted by Metal Brain
Our climate is not even close to being as warm as the Pliocene. CO2 is not the primary factor driving global warming. If it was we would be a lot warmer than we are.....period. Anybody can pretend this inconvenient fact does not exist, but it does. All you do is post web links that don't prove anything. Why is that? Is that the best you can do?
This is a common trope of yours. And it's unbelievably stupid.
Imagine you are lying on your bed, it's freezing cold an you are shivering.
So you do what any sensible person would do, and you get under the duvet.
The duvet adds a layer of insulation between you and the cold air in your room,
and traps a layer of air around you.
However, the duvet is also cold, as is the air you have just trapped.
The added insulation has not made you instantly warm.
However as your body emits heat, the air and duvet warm up, and the temperature
under the duvet slowly climbs to the equilibrium temperature for a person lying under
that much insulation for the given temperature of the room.
Adding CO2 to the atmosphere is analogous to adding insulation [although it's a lot
more complicated] and in the same way it doesn't instantly make it hotter.
What it does is introduce an energy imbalance [that can be, and has been measured]
that will continue to raise the temperatures [heat content] until a new equilibrium is reached.
Some examples:
1) Heating the atmosphere over the oceans increases the rate of heat flow from the air into
the oceans. This causes the oceans to heat up.
However, just as putting a pan of cold water onto a stove does not cause it to instantly boil,
so increasing the rate of heat flow into the oceans doesn't cause them to instantly heat up
to equilibrium point. The oceans being unbelievably massive, and water having an impressively
high heat capacity. [much greater than that of the atmosphere]
This means that the oceans suck heat out of the atmosphere and lead to lower atmospheric temperatures
until the oceans have warmed up. [similarly with rocks/the earth but to a much less extent]
2) Their are large land and ocean ice caps/glaciers. These huge lumps of ice take energy to heat them
up and then even more energy to convert them from zero degree ice to zero degree water.
This is why having ice in you drink keeps it cool, the heat melts the ice instead of raising the temperature.
Additionally, the white surface reflects far more light than the oceans or rocks underneath and thus
reduce the amount of heating that region receives. As the ice 'slowly' melts it exposes more land/ocean
surface which increases the amount of heat energy the Earth absorbs further warming the planet.
This is a feedback loop, where warming causes further warming.
This process takes time, there are million and millions of cubic km of ice to melt.
As this ice melts, it dumps huge quantities of freezing water into the oceans, cooling them down.
This acts to slow the oceans temperature rise introducing another delay on the system reaching
a new equilibrium.
3) A large [majority] of the warming caused by an increase in CO2 levels is both predicted and observed
to be caused by an increase in the water vapour content of the air [water vapour being a much stronger
greenhouse gas] caused by the increase in the water carrying capacity of the warmer air. This is another
positive feedback loop. Such feedback loops take time to steadily build and are not instantaneous.
That will do for now.
In short the idea that the planet should have warmed to the temperatures of the Pliocene when we reached the
'same' CO2 concentrations last year, given the vast thermal capacity of the Earth's climate system, is idiotic
and absurd in the extreme.
And is not a sentiment that any real scientist of any stripe could possibly contemplate.