Now new research led by Cardiff University, with scientists in the UK and US, reveals that these ocean circulation changes may have been more dramatic than previously thought. The findings, published January 14, 2011 in the journal Science, show that as the last Ice Age came to an end (10,000 -- 20,000 years ago) the formation of deep water in the North-East Atlantic repeatedly switched on and off. This caused the climate to warm and cool for centuries at a time.