Plants and animals are fleeing the effects of climate change far faster than experts suspected, new research has shown.
Scientists estimate that species are moving away from the Earth's warm equatorial belt at a rate equivalent to 20 centimetres (8in) per hour.
Migration towards the poles since the early 1970s has been three times more rapid than earlier studies indicated.
Movements up hills and mountains, to cooler higher altitudes, have been twice as fast.
A team of British-led scientists uncovered the trend after analysing data on more than 2,000 responses by plant and animal species.
The researchers calculated that every ten years on average species had moved 17.6 kilometres in the direction of the poles.Shifts to higher elevations were at the rate of 12.2 metres per decade.
Lead scientist and conservation biologist Professor Chris Thomas, from the University of York, said: "These changes are equivalent to animals and plants shifting away from the equator at around 20 centimetres per hour, for every hour of the day, for every day of the year. This has been going on for the last 40 years and is set to continue for at least the rest of this century."
The study, reported in the journal Science, shows a clear link between species migrations and climate change. Plants and animals in regions most affected by global warming are those that have moved the furthest, say the researchers.
Co-author Dr I-Ching Chen, from the Academia Sinica in Taiwan, said: "We have for the first time shown the amount by which the distributions of species have changed is correlated with the amount the climate has changed in that region."
At the individual level, the study revealed wide variation between the movement patterns of different species.
Some species had moved more slowly than expected and others had stayed put, while a proportion had retreated instead of expanded.
But a number of species had raced away, possibly driven by a particular aspect of climate change or other alterations in the environment.
Dr David Roy, another team member from the University of York's Centre for Ecology & Hydrology, said: "In Britain, the high brown fritillary butterfly might have been expected to expand northwards into Scotland if climate warming was the only thing affecting it, but it has in fact declined because its habitats have been lost. Meanwhile, the comma butterfly has moved 220 kilometres northwards from central England to Edinburgh, in only two decades."
Similar variation had taken place in other animal groups. Cetti's warbler, a small brown bird with a loud voice, moved north in Britain by 150 kilometres while the Cirl bunting retreated south by 120 kilometres.
Professor Thomas said: "Realisation of how fast species are moving because of climate change indicates that many species may indeed be heading rapidly towards extinction, where climate conditions are deteriorating.
"On the other hand, other species are moving to new areas where the climate has become suitable, so there will be some winners as well as many losers."