[BEIJING] Many physical and ecological systems are being affected by the world's warming climate, researchers say.
Scientists from across the world applied statistical models to published data on changes in 829 physical systems and around 28,800 plant and animal systems —on both global and continental scales — some with data going back to 1970.
Their analysis, published in Nature last week (15 May), looked at whether these changes were related to temperature increase, other factors such as land use change, or simply natural variability.
Around 95 per cent of the physical systems studied responded to the world's warming trend. The analysis found that glaciers in every continent have been shrinking, permafrost is melting, the peak of river levels in spring is shifting, and lake and river temperatures are rising.
And 90 per cent of the changes in plants and animals were consistent with responses to temperature rise, including earlier blooming and leaf unfolding.
The authors found little evidence that natural variability or other environmental factors were significant, and conclude that climate change is affecting these systems.
Their findings are largely consistent with the report by the second working group of the Intergovernmental Panel on Climate Change (IPCC WG-2), which says more than 89 per cent of the significant changes in physical and biological systems are consistent with global warming. The IPCC fourth assessment report concluded it is "likely" that global warming is human-induced.
Cynthia Rosenzweig, lead author and scientist at the US-based NASA Goddard Institute for Space Studies, told SciDev.Net that the study expanded the work by IPCC WG-2, extending the analysis to the continental scale.
The researchers also call for more sensitive observation networks documenting responses to warming, especially in tropical and subtropical regions.
Co-author Liu Chunzen, from the China Water Information Centre, says that, in China, "delicate studies on the nuances of changes in plants and animals responding to the warming are severely lacking."
Nature 453, 353 (2008)