BBC NEWS | Science/Nature | Warming 'very likely' human-made
Warming 'very likely' human-made
By Richard Black
Environment correspondent, BBC News website, Paris
Residents in New Orleans' 9th Ward in September 2005
The IPCC is likely to back a link from warming to stronger storms
Climatic changes seen around the world are "very likely" to have a human
cause, the Intergovernmental Panel on Climate Change (IPCC) will conclude.
By "very likely", the IPCC means greater than 90% probability.
This is a stronger position than the global organisation took in its
last major report in 2001.
IPCC scientists have yet to finalise other elements - including
forecasts of sea level rise - in their report due to be published on Friday.
Experts have been divided on whether to go with a conservative forecast
in the order of half a metre increase over the coming century, based on
computer models which exclude the melting of icecaps, or whether to
include estimates of how much water the Greenland and West Antarctic
sheets are likely to contribute.
The exact wording on projections of global temperature increase have
also yet to be finalised, though the agency is likely to say that by the
end of the century temperatures will rise by between about 2C and about
This week's deliberations in the French capital, Paris, will lead to a
summary of the current state of climate science, drawing on the work of
thousands of researchers.
Carbon dioxide concentrations have risen steadily in recent years
The full climate science report will be released later in the year, as
will other IPCC chapters looking at the probable impacts, options for
adapting to those impacts, and possible routes to reducing emissions of
But the climate science summary is attracting a huge amount of interest
from politicians, other scientists, and environment groups because the
IPCC's mandate is to state the definitive scientific position.
Speaking in Nairobi, United Nations Environment Programme (Unep)
executive director Achim Steiner told reporters the findings should be
"the full stop behind any arguments over what was causing global warming".
The IPCC is likely to give some backing to a theory which has proved
highly controversial in recent years by concluding that it is likely -
meaning a greater probability than 66% - that rising temperatures have
contributed to the development of more powerful tropical storms in some
areas of the world.