Equine Health Update Issue 1 Volume 16 - Page 12

of about 125,000 years ago. This is the last interglacial period, when the North Atlantic was warmer, fresher and sea level was higher than it is today and looked a lot like what climate models predict it will look by the end of this century. “At that time, there were a series of sudden and large reductions in the influence of these North Atlantic waters in the deep ocean. These deep water reductions occurred repeatedly, each lasting for some centuries before bouncing back. The unstable circulation operated as if it was near a threshold and flickered back and forth across it,” says Eirik Vinje Galaasen, a PhD student and now researcher at UiB’s Department of Earth Science, who is the lead author of the paper published in the journal Science. cooling effect of ocean circulation changes. In any event, the super cooling or slide into the next ice age as popularised in a Hollywood blockbuster did not occur. Will this happen to the future Earth? Many models have actually predicted a slow and gradual decline in North Atlantic circulation over the next century. However, different models offer widely different scenarios for what will happen in the future. While the climate of the last interglacial is not exactly what will be the case in a future greenhouse world, it does share some features, including being fresher and warmer by a few degrees Celsius in the northern Atlantic. “These types of changes hadn’t been noticed before because they are so short-lived. Geologists hadn’t focused on century scale ocean changes because they are difficult to detect,” adds Professor Ulysses Ninnemann, from UiB’s Department of Earth Science and Galaasen’s PhD adviser. Training models, if models can capture the types of changes we see in the past, may also be doing a good job at predicting the future. The seafloor evidence suggests that there were large and fast changes in circulation the last time the ocean looked the way it may look by the end of this century. “Our study demonstrates that deep water formation can be disrupted by the fresheni