Earth's Climate Evolution - a New (Geological) Perspective
Speaker: Dr Colin P. Summerhayes (Emeritus Associate, Scott Polar Research Institute)
The statement that ‘the climate is always changing’ is only meaningful if we know the drivers of that change, which we can find from studies of the geological record. Moreover, as Scottish geologist James Hutton pointed out in 1795, knowing the past will help us to predict the future if past conditions recur. What we find in the rocks will support or disprove what climate models tell us.
Scientists began speculating about climate change late in the 18th century. Subsequent scientific and technological developments have led to formulation of a coherent theory of climate change. We have come a long way from the notion that erratic blocks of rock on British hills were deposited by Noah's flood. The past 30 years have seen dramatic advances in our knowledge of the variability of past climate change and its causes, enabling us to understanding what our climate is doing now and may do next.
Much of what we know comes from examining cores of marine sediment, along with ice cores, stalactites, tree rings and corals. Over the past one million years our climate has operated within narrow envelopes governed by orbital change and solar change. Over the past 2000 years those natural changes drove us into the Little Ice Age. Present orbital and solar properties are like those of the Little Ice Age, yet temperatures have begun rising.
The only driver we can find to explain that divergence, in keeping with what we know of the drivers of past change, is the rise in CO2 emissions. One is reminded of the saying that those who ignore the past are doomed to repeat it.
About the speaker
Colin Summerhayes is a marine geochemist expert in determining past climates by studying marine sediments. An Emeritus Associate at the Scott Polar Research Institute of Cambridge University, he has been Executive Director of the International Council for Science's Scientific Committee on Antarctic Research (SCAR), Director of the Global Ocean Observing System (GOOS) Project Office at UNESCO's Intergovernmental Oceanographic Commission in Paris, Director of the UK's Institute of Oceanographic Sciences Deacon Laboratory (Wormley), and Deputy Director of the Southampton (now National) Oceanography Centre. He has worked in academia, government and industry (BP and EXXON). His books include "Oceanography - an Illustrated Guide", "Antarctic Climate Change and the Environment", and "Earth's Climate Evolution"