Too hot… too cold… just right: new book explains Earth’s finely balanced climate

Posted by mjs76 at Mar 27, 2012 11:50 AM |
Author signing at the University Bookshop this Thursday.

Two Leicester geologists have a new popular science book out which documents “the four billion year story of Earth’s climate”. The Goldilocks Planet takes its name from a phrase coined a couple of years ago to describe extrasolar worlds which fall into a ‘habitable zone’ around their parent star. And the most prominent, best-known Goldilocks planet is, of course, this one.

Mars is too far away from the Sun and therefore too cold. It may have had primitive life once but there is nothing there now unless some microbes have survived, frozen in the ice caps. Venus is too close to the Sun and way too hot. But Earth is like Baby Bear’s porridge: just right.*

Furthermore, the Earth has been ‘just right’ for about 3.8 billion years, through all manner of changes to the land, the oceans, the ice caps, the atmosphere, the biomass of flora and fauna thereon and the warmth provided by the Sun, not to mention the occasional damn great meteorite whacking into the planet and causing mass extinction.

This new book has been written by Dr Jan Zalasiewicz and Dr Mark Williams from our Department of Geology. Jan is a field geologist, palaeontologist, and stratigrapher who specialises in researching fossil ecosystems and environments; his previous critically acclaimed works include The Earth After Us and The Planet in a Pebble. For this volume he has teamed up with Mark, a former British Antarctic Survey scientist who has published dozens of papers on how the climate has changed over geological timescales.

‘Climate change’ is a hot potato today, both scientifically and politically, but to understand how human activity is affecting the climate one must first grasp how the climate has changed since, well, since we first had a climate. And, crucially, the ways in which the climate has, up to now, stayed basically the same, enabling the great diversity of life on Earth to flourish (the occasional meteorite notwithstanding).

Earth climate from 4.56 billion years ago to present. The Earth’s earliest climate state may, perhaps, have been super-warm. Icehouse climates began during the Archaean. Long-term intervals of greenhouse climate were punctuated by glaciations in the early and late Proterozoic that may have been Snowball Earth events. The glaciations of the Phanerozoic were less extensive, never extending to within 30° of the equator.

Jan and Mark’s book is therefore essential reading for anyone with an interest in climate change, and it is eminently readable and accessible to anyone with a lay interest in science. Published by OUP, The Goldilocks Planet has a cover price of £16.99 but is available from the University Bookshop for just £13.99 and if you come along to the Bookshop this Thursday you can get a signed copy.

Jan will be signing the book in the University Bookshop (located within our David Wilson Library) from 5.30pm on Thursday 29 March 2012. Mark, unfortunately, is out of the country on that date.

And once you’re here, why not take in one of three events happening at 6.00pm on Thursday? You have a choice of lectures: the Rattray Lecture Theatre for a talk on our 1960s Engineering Building, or the Ken Edwards Building for a talk on English castles. Or just up the road in St Stephen’s Church our Chaplaincy presents readings and music to celebrate Easter. Something for everyone at the University of Leicester this week.

Also worth noting is that the term ‘Goldilocks Planet’ is set to receive widespread awareness this summer as it is a major plot point of Hollywood’s latest alien invasion epic Battleship. Which can’t hurt sales of the book…

Peering through the rubble of three billion years to try to find indications of Archaean climate is a little like the challenge scientists faced in trying to understand Mars, before our spacecraft reached that planet. As little as half a century back, the dark patches on this planet could be seriously interpreted as vegetation—vast spreads of lichen, perhaps—from the pattern of their spectra as analysed by the best Earth-based telescopes. And only a hundred years ago, there was not only serious scientifi c discussion of the possibility of canals on that planet, but speculation that teams of windmills could pump water into their upper reaches, to make and store power for an ancient Martian civilization.

We are similarly groping with patchy, inadequate data to try to make sense of the climate of the early Earth. We know, at least, that the climate could not have been ice-bound. But, even if we also know that the oceans did not boil away—just how hot could it have been, three billion years ago?
The Goldilocks Planet by Jan Zalasiewicz and Mark Williams


*The scientific flaw in the Three Bears story is that a larger bowl means greater surface area so faster cooling. Therefore the sequence should be: Daddy Bear’s porridge too cold, Baby Bear’s porridge too hot, Mummy Bear’s porridge just right.