U.S. Department of the Interior
U.S. Geological Survey
News Release
March 15, 2006 Thomas Huntington 207-622-8201 ext.110 thunting@xxxxxxxx
Diane Noserale 703-648-4333 dnoseral@xxxxxxxx
Century of Data Shows Intensification
of Water Cycle but No Increase in Storms or Floods
Editors: Copies of the
report “Evidence for intensification of the global water cycle: Review
and synthesis,” are available to reporters from the author.
A review of the findings from more
than 100 peer-reviewed studies shows that although many aspects of the
global water cycle have intensified, including precipitation and evaporation,
this trend has not consistently resulted in an increase in the frequency
or intensity of tropical storms or floods over the past century. The USGS
findings, which have implications on the effect of global climate change,
are published today in the Journal of Hydrology.
“A key question in the global
climate debate is if the climate warms in the future, will the water cycle
intensify and what will be the nature of that intensification,” said USGS
scientist Thomas Huntington, who authored the study. “This is important
because intensification of the water cycle could change water availability
and increase the frequency of tropical storms, floods, and droughts, and
increased water vapor in the atmosphere could amplify climate warming.”
For the report, Huntington reviewed
data presented in more than 100 scientific studies. Although data are not
complete, and sometimes contradictory, the weight of evidence from past
studies shows on a global scale that precipitation, runoff, atmospheric
water vapor, soil moisture, evapotranspiration, growing season length,
and wintertime mountain glacier mass are all increasing. The key
point with the glaciers is that there is more snowfall resulting in more
wintertime mass accumulation – another indication of intensification.
“This intensification has been
proposed and would logically seem to result in more flooding and more intense
tropical storm seasons. But over the observational period, those
effects are just not borne out by the data in a consistent way,” said
Huntington.
Huntington notes that the long
term and global scale of this study could accommodate significant variability,
for example, the last two Atlantic hurricane seasons.
“We are talking about two possible
overall responses to global climate warming: first an intensification
of the water cycle being manifested by more moisture in the air, more precipitation,
more runoff, more evapotranspiration, which we do see in this study; and
second, the potential effects of the intensification that would include
more flooding and more tropical storms which we don’t see in this study,”
said Huntington.
The USGS serves the nation by providing
reliable scientific information to: describe and understand the Earth;
minimize loss of life and property from natural disasters; manage water,
biological, energy, and mineral resources; and enhance and protect our
quality of life.
*** USGS ***
Diane Noserale
Media Relations, Eastern Region
U.S. Geological Survey
150 National Center
Reston, VA 20192
phone: 703-648-4333
fax: 703-648-4588
