However, recent warming is the result of many natural and man - made factors, and it is extraordinarily difficult to assign all the
blame for current warming to man.
The other thing that bothers me is that if one of the lines of
evidence for the current warming having man's fingerprint is that the models without man's influence do not coincide with reality that is warmer.
The original topic of the conversation was whether Romm's graph made a convincing
case for the current warming being unusual and concerning in the context of Holocene history.
The charts I did are around pages 6 - 7 of the pdf, the ones showing the projected curve of global warming for various climate sensitivities, and backing into what that should
imply for current warming.
Using a time period when CO2 did not change at all, to support a general conclusion that «CO2 is not the driver of climate change» and hence is not
responsible for the current warming, is hardly logical.
The bottom line is that regardless of whether or not the D - O cycles are triggered by the Sun, the timing is clearly not right for this cycle to be responsible
for the current warming.
Bond et al. (1999) added further evidence that the timing of D - O events disqualifies them from being responsible
for the current warming, by showing that the most recent D - O event may have contributed to the Little Ice Age (LIA):
Raypierre and also Chris (comment 29) noted that «sceptics» should not just magically forget about or omit the established greenhouse gas physics when trumpeting exotic solar explanations
for current warming.
Using a time period when CO2 did not change at all, to support a general conclusion that «CO2 is not the driver of climate change» and hence is not responsible
for the current warming, is hardly logical.
I don't see how anyone can still cling to the cosmic ray theory of climate change (at least as an explanation
for current warming) given these facts.
If it is so, then how can we give any credence to the theory that human CO2 output, alone, is responsible
for current warming?
The bottom line is that regardless of whether or not the D - O cycles are triggered by the Sun, the timing is clearly not right for this cycle to be responsible
for the current warming.
Bond et al. (1999) added further evidence that the timing of D - O events disqualifies them from being responsible
for the current warming, by showing that the most recent D - O event may have contributed to the Little Ice Age (LIA):