This is likely to have contributed to the spike in warmth in 1940, but there is insufficient BC
in glacial records at that time for it to be the primary explanation.
It compares them
with glacial records from nearby mountains to reveal how glaciers behave in extreme climates.
While this is controversial, in any case there must be some sort of feedback from temperature to atmospheric carbon to account for certain aspects of
the glacial record.
Emphasize that we are now matching the warmest climate seen in
the glacial record.