By Roger Highfield Science Editor
Last Updated: 3:18AM BST 15 May 2008
Researchers who analysed 30,000 academic studies dating back to 1970 said man was responsible for changes that ranged from the loss of ice sheets to the collapse in numbers of many species of wildlife.
"Humans are influencing climate through increasing greenhouse gas emissions, and the warming world is causing impacts on physical and biological systems," said Cynthia Rosenzweig, at the Nasa Goddard Institute for Space Studies.
The effects on living things include the earlier appearance of leaves on trees and plants; the movement of animals and birds to more northerly latitudes and to higher altitudes in the northern hemisphere; rapid advances in flowering time and earlier egg-laying in Britain; and changes in bird migrations in Europe, North America and Australia.
On a planetary scale the changes include the melting of glaciers on all continents; earlier spring river run-off; and the warming of oceans, lakes and rivers.
The study's conclusions go further than the most recent report by the Intergovernmental Panel on Climate Change, which concluded last year that man-made climate change was "likely" to have had a discernible effect on the planet.
It says natural climate variations cannot explain the changes to the Earth's natural systems.
In the study, published in the journal Nature, Miss Rosenzweig and researchers from 10 institutions across the world analysed data from published papers on 829 physical systems – such as glaciers and ice sheets – and 28,800 plant and animal systems. They produced a picture of the changes to each continent. The changes were most marked in North America, Asia and Europe but mainly because far more studies had been carried out there.
more:
http://www.telegraph.co.uk/news/worldnews/1955916/Mankind-is-the-Earths-biggest-threat.html