that geography was weakened by being split into two disciplines instead of playing to its strengths as the only subject that can offer holistic study of pressing environmental concerns. "We have got this schism between physical geography and human geography," the Plymouth University academic said. "They don't often talk to teach other and use different methodologies and all the rest of it.
"But for a lot of the key issues that we deal with - climate change, shale gas - that dichotomy about whether it is about understanding the human system or the natural system is completely pointless. It is an artefact for the 20th century."
Professor Stewart believes that unless geography exploits its position as the most interdisciplinary subject, it risks being sidelined by rivals such as sociology and economics on the human side and geology and engineering on the physical side.
"Geography is going to end up being smeared out unless it captures that middle ground," the academic said. "It will end up losing its market share."
He made the same arguments to teachers at the Geographical Association conference in Guildford last week. Association chief executive Alan Kinder said: "I am more than in agreement. Geography is about teaching children to think in a holistic way."
Professor Stewart said teachers learned to fall into either the human or physical geography camp at university. And the divisions were perpetuated by materials such as the government's subject content for the new geography GCSE, which was "keeping these little pigeon holes going".
"This notion that the best thing to do is to separate our study into the human bit and the physical bit is not fit for the 21st century," he claimed.
The Geographical Association advised on the new national curriculum for England, Wales and Northern Ireland, in which the humanphysical split is maintained. But Mr Kinder said: "Teachers are going to need to put those elements together. We should be talking about a joined-up geography."
Professor Stewart has appeared in a string of TV documentary series on topics from the formation of the Earth's continents to tsunamis and avalanches. "When I started making programmes, I said I was a geologist. People across the table had no idea what geology was. It sounded boring - stones, for God's sake. But as soon as I showed them it wasn't that, it was about volcanoes and earthquakes, they go `Oh, that's really interesting'.
"The trouble was, you couldn't do that trick with geography because everyone thought they knew what geography was. In the public perception, geography is like a nice, comfortable pair of slippers. It is about the things you learned at school that weren't that important but were quite interesting."
Professor Stewart described series fronted by Michael Palin, Bruce Parry and Simon Reeve as travelogues that are "quite interesting but.not very substantive". He added: "The TV is the shop window. But if people stick their heads in, what more will draw them into the shop? It is our problem as geographers and if we sort ourselves out people will take us more seriously."
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To read more about changes to the primary and secondary geography curriculum, and to get involved in the debate, go to www.tesconnect.comgeographyweek