A survey of 26 mountain summits over 3,000 metres above sea level has shown a dramatic increase in the number of plants able to survive at high altitudes.
Scientists believe the movement is the direct result of an increase in temperature of less than one degree Celsius over the same period. They also believe the trend could soon lead to many species becoming extinct as the summits become increasingly crowded.
As fast-growing plants from lower slopes move higher, the slow-growing species that grow at higher altitudes become overwhelmed, said Georg Grabherr, professor of ecology at Vienna University: 'They are finished because there is nowhere left. Their only chance is to go to heaven.'
Professor Grabherr and his colleagues Michael Gottfried and Harald Pauli compared the number of species now living on the high slopes with those recorded between 70 and 90 years ago.
Their research, published in this week's Nature, concluded: 'There is no doubt that even moderate warming induces migration processes, and that this process is under way . . . global warming is already having a significant effect on alpine plant ecology.'
'Even in situations where plants must move upwards, the warming is sufficient to stimulate migration, and may cause disastrous extinctions in these environments.' The scientists have calculated some species are moving up at a rate of about four metres a decade. Mr Pauli said the average annual temperature rise over the past 70 to 90 years of 0.7C was responsible for the upward movement.
'The limiting factor for plant growth in higher regions of the Alps is temperature. Less than one degree may not seem much but it is enough to make some plants able to survive higher up.'Reuse content