MARRAKESH - Most life on Earth is already being changed by the warming climate, even though the rise in global temperature since pre-industrial times has been rather slight, researchers warned on Thursday.
The study in the journal Science found that 82 percent of key ecological processes -- including genetic diversity and migration patterns -- are being altered by global warming.
These effects extend to land, oceans and freshwater environments, even though temperatures have risen just about 1.87 degrees Fahrenheit (1 degree Celsius) over pre-industrial times due to fossil fuel burning.
"We now have evidence that, with only about one degree C of warming globally, major impacts are already being felt," said lead study author Brett Scheffers, member of the International Union for Conservation of Nature Climate Change Specialist Group and assistant professor at the University of Florida.
"These range from individual genes changing, significant shifts in species' physiology and physical features such as body size, and species moving to entirely new areas."
These changes will affect humans by causing disease outbreaks, inconsistent crop yields and cutting down on fishery productivity, threatening food security, experts said.
The study, which analyzed 94 ecological processes as documented in peer-reviewed literature, also warned that the more ecosystems change, the less likely they may be to guard against the harshest effects of climate change.
Unhealthy forests will no longer be able to sequester large amounts of carbon, for instance.
Increasingly warm oceans will no longer act as a an effective buffer against temperature rise, and climate-related floods, sea-level rise and cyclones will get worse.
Since people depend on healthy ecosystems for food and clean water, the more the natural environment changes, the more people's livelihoods will be at risk.
"We are simply astonished at the level of change we observed, which many of us in the scientific community were not expecting for decades," said senior author James Watson from the University of Queensland and Wildlife Conservation Society, member of the IUCN Climate Change Specialist Group.
"It is no longer sensible to consider this a concern for the future, and if we don't act quickly to curb emissions it is likely that every ecosystem across Earth will fundamentally change in our lifetimes."