In their study, scientists compared sea-surface temperatures in the southwest Atlantic to their index of the yearly calving success of whales that breed off the Argentine coast.
Researchers found a strong correlation between the number of right whale calves born and changes in sea-surface temperature in the autumn of the preceding year.
Other experts say the study results are convincing. Charles H. Greene, professor of earth and atmospheric science at Cornell University in Ithaca, New York, said: "The authors provide compelling evidence that South Atlantic right whale calving rates are correlated with climate variability, once one takes into account the appropriate time lags."
The study authors were able to chart the sea-surface temperature against whale calf output for the years 1983-2000, and the results were clear: As the water temperatures rise from the norm, calf output declines.