The proportion of 15-year-olds taking geography GCSE fell from 37.4 to 30.6 per cent between 2000 and 2004, when it attracted fewer candidates than history for the first time.
The Royal Geographical Society and the Geographical Association say that while the subject is still popular, it has suffered from a lack of expert teaching and a failure to keep up with world events.
"Geography in the popular imagination is 'What is the capital of this country?' or 'What is the longest river?'," said David Lambert, the Geographical Association's chief executive.
"But it can be far more stimulating - climate change, global warming, the future of the Middle East. It has the power to help people understand all these things and has never been as important as it is today."
Now the two organisations are hoping the two-year scheme they have devised with the Government will improve teaching and make the subject a more popular GCSE and A-level option.
Ministers launched the plan by sending a copy of Mr Palin's best-selling book Himalaya to every English secondary school.
Mr Palin said: "You can travel the seas, poles, and deserts and see nothing. To really understand the world you need to get under the skin of the people and places. In other words, learn about geography. I cannot imagine a subject more relevant in schools."
Beyond the celebrity endorsement there is a new chartered geography teacher status and a website for teachers to be known as Geography Teaching Today.
The plan also aims to support teachers through extra training and resources to help make the subject more enjoyable. But Alex Standish, from Rutgers university, New Jersey, claims it fails to address the problem that ethics are replacing knowledge as the subject's cornerstone.
"The geography curriculum has become laden with topics of environmental protection, preservation and respect for traditional and primitive cultures, and stories of the downtrodden," he writes in The TES this week.
"Empathy and respect have replaced moral judgment and the pursuit of truth as curricular goals."
Weaknesses in geography teaching have been identified by Ofsted at primary and key stage 3. Rita Gardner, RGS director, who together with Mr Lambert has been appointed geography adviser to the Education Secretary, explained this was because a quarter of geography lessons for 11 to 14-year-olds were taught by non-specialists.
She added: "The curriculum has not been changed since the 1980s and is frankly not the most exciting to teach."
The plan aims to stimulate pupil interest by giving teachers the information they need to teach the geography of their own areas.
Many teachers in Hampshire already devise their own lesson plans, helped by county geography adviser Jeff Stanfield. At Yateley infants, even young pupils are encouraged to get out and about, progressing from following teddy bear trails around school to visiting the seaside town of Southsea.
Natalie Magee, seven, said: "I like going outside because you go to places you've not been to before and find out new things."
The national action plan, to be in place by September, will include a geography ambassadors programme, in which students who have studied or are studying the subject at university promote it in at least 500 schools.