Open Eye: Pollen clues to secrets of the planet

TO SEE A World in a Grain of Sand... wrote Blake, unknowingly predicting the direction of one OU research study in which single pollen grains are being used to build a picture of what the planet looked like 120,000 years ago.

PhD student Siobhan McGarry is releasing the tiny particles of pollen from stalagmites in which they've been imprisoned in order to add to the mass of evidence science is accumulating in its urgent quest to understand what is happening with the earth's climate. By identifying the species from which each pollen grain comes, and matching it with what we know about particular plants' likes and dislikes, Siobhan is able to work out what climactic conditions were like the last time a 'brief' spell of warm weather interrupted the Ice Age.

While pollen studies have been done before, the fact that it is possible to date the age of stalagmites back some 350,000 years means this study should also provide evidence of climactic change. This will fuel the debate about whether the threat of global warming is a real one, something which would have occurred naturally anyway, or, alternatively, that we are at much greater risk of slipping back into another Ice Age.

Working from broken or donated stalagmites from two caves in Yorkshire, and a site in the Mendips, Siobhan has also discovered fungal spores and even the occasional piece of insect.

She explained: "From these little pieces of evidence we can work out soil, moisture, climactic conditions. I can say that 120,000 years ago there were oak trees growing over a cave in Yorkshire which indicates that the climate was warm and possibly a couple of degrees warmer than now, because there is only grass there now.

Her project's echoes of Jurassic Park have already caught the attention of the BBC who will feature Siobhan in a new programme at the end of this month: The Essential Guide to the Weather.

However, Siobhan is wary of making any great claims for the research, which is being done jointly by the OU and Exeter University. "You have got all these different clues and have to try to build them into a picture which helps us figure out the underlying effects. Is warming happening naturally - or are we putting off the next ice age?"