Data from end of the last Ice Age confirm effects of climate change on oceans.
Data from end of the last Ice Age confirm effects of climate
change on oceans
The first comprehensive study of changes in the oxygenation of
oceans at the end of the last Ice Age (between about 10 to 20,000
years ago) has implications for the future of our oceans under
global warming. The study, which was co-authored by Eric Galbraith,
of McGill's Department of Earth & Planetary Sciences, looked at
marine sediment and found that that the dissolved oxygen
concentrations in large parts of the oceans changed dramatically
during the relatively slow natural climate changes at the end of
the last Ice Age. This was at a time when the temperature of
surface water around the globe increased by approximately 2 °C over
a period of 10,000 years. A similar rise in temperature will result
from human emissions of heat-trapping gases within the next 100
years, if emissions are not curbed, giving cause for concern.
Most of the animals living in the ocean, from herring to tuna,
shrimp to zooplankton, rely on dissolved oxygen to breathe. The
amount of oxygen that seawater can soak up from the atmosphere
depends on the water temperature at the sea surface. As
temperatures at the surface increase, the dissolved oxygen supply
below the surface gets used up more quickly. Currently, in about 15
per cent of the oceans - in areas referred to as dead zones -
dissolved oxygen concentrations are so low that fish have a hard
time breathing at all. The findings from the study show that these
dead zones increased significantly at the end of the last Ice
"Given how complex the ocean is, it's been hard to predict how
climate change will alter the amount of dissolved oxygen in water.
As a result of this research, we can now say unequivocally that the
oxygen content of the ocean is sensitive to climate change,
confirming the general cause for concern."
This research was funded by the Natural Sciences and Engineering
Research Council of Canada (NSERC) and the Canadian Institute for
Advanced Research (CIFAR).
The results of this study were published in Nature
PHOTO: Dead Sea by David Shankman (Wikipedia)