Date: May 9, 2014 3:11 PM
Author: Jerry P. Becker
Subject: [ncsm-members] Gen'l Interest: U.S. Climate Has Already Changed, Study Finds
From The New York Times, Tuesday, May 6, 2014. See
U.S. Climate Has Already Changed, Study Finds, Citing Heat and Floods
By Justin Gillis
SIDEBAR MAP-ILLUSTRATION: Rising Temperatures
1991-2012 average temperature compared with 1901-1960 average ---
The effects of human-induced climate change are being felt in every
corner of the United States, scientists reported Tuesday, with water
growing scarcer in dry regions, torrential rains increasing in wet
regions, heat waves becoming more common and more severe, wildfires
growing worse, and forests dying under assault from heat-loving
Such sweeping changes have been caused by an average warming of less
than 2 degrees Fahrenheit over most land areas of the country in the
past century, the scientists found. If greenhouse gases like carbon
dioxide and methane continue to escalate at a rapid pace, they said,
the warming could conceivably exceed 10 degrees by the end of this
"Climate change, once considered an issue for a distant future, has
moved firmly into the present," the scientists declared in a major
new report assessing the situation in the United States.
"Summers are longer and hotter, and extended periods of unusual heat
last longer than any living American has ever experienced," the
report continued. "Winters are generally shorter and warmer. Rain
comes in heavier downpours. People are seeing changes in the length
and severity of seasonal allergies, the plant varieties that thrive
in their gardens, and the kinds of birds they see in any particular
month in their neighborhoods.
The report is the latest in a series of dire warnings about how the
effects of global warming that had been long foreseen by climate
scientists are already affecting the planet. Its region-by-region
documentation of changes occurring in the United States, and of
future risks, makes clear that few places will be unscathed - and
some, like northerly areas, are feeling the effects at a swifter pace
than had been expected.
Alaska in particular is hard hit. Glaciers and frozen ground in that
state are melting, storms are eating away at fragile coastlines no
longer protected by winter sea ice, and entire communities are having
to flee inland - a precursor of the large-scale changes the report
foresees for the rest of the United States.
The study, known as the National Climate Assessment, was prepared by
a large scientific panel overseen by the government and received
final approval at a meeting Tuesday. [See
The White House, which released the report, wants to maximize its
impact to drum up a sense of urgency among Americans about climate
change - and thus to build political support for a contentious new
climate change regulation that President Obama plans to issue in June.
But instead of giving a Rose Garden speech, President Obama spent
Tuesday giving interviews to local and national weather broadcasters
on climate change and extreme weather. The goal was to help Americans
connect the vast planetary problem of global warming caused by carbon
emissions from cars and coal plants to the changing conditions in
their own backyards. It was a strategic decision that senior White
House staff members had been planning for months.
Speaking to Al Roker of NBC News, in an interview scheduled to be
shown Wednesday morning on the "Today" show, Mr. Obama said "This is
not some distant problem of the future. This is a problem that is
affecting Americans right now. Whether it means increased flooding,
greater vulnerability to drought, more severe wildfires - all these
things are having an impact on Americans as we speak."
In the Northeast, the report found a big increase in torrential rains
and risks from a rising sea that could lead to a repeat of the kind
of flooding seen in Hurricane Sandy. In the Southwest, the water
shortages seen to date are likely just a foretaste of the changes to
come, the report found. In that region, the report warned, "severe
and sustained drought will stress water sources, already overutilized
in many areas, forcing increasing competition among farmers, energy
producers, urban dwellers and plant and animal life for the region's
most precious resource."
The report did find some benefits from climate change in the short
run, particularly for the Midwest, such as a longer growing season
for crops and a longer shipping season on the Great Lakes. But it
warned that these were likely to be countered in the long run by
escalating damages, particularly to agriculture.
"Yes, climate change is already here," said Richard B. Alley, a
climate scientist at Pennsylvania State University who was not
involved in writing the report. "But the costs so far are still on
the low side compared to what will be coming under business as usual
by late in this century."
The report was supervised and approved by a large committee
representing a cross section of American society, including
representatives of two oil companies. [see
http://www.nesdis.noaa.gov/NCADAC/People.html ] It is the third
national report in 14 years, and by far the most urgent in tone,
leaving little doubt that the scientists consider climate change an
incipient crisis. It is also the most slickly produced, with an
elaborate package of interactive graphics on the Internet.
One of the report's most striking findings concerned the rising
frequency of torrential rains. Scientists have expected this effect
for decades because more water is evaporating from a warming ocean
surface, and the warmer atmosphere is able to hold the excess vapor,
which then falls as rain or snow. But even the leading experts have
been surprised by the scope of the change.
The report found that the eastern half of the country is receiving
more precipitation in general. And over the past half-century, the
proportion of precipitation that is falling in very heavy rain events
has jumped by 71 percent in the Northeast, by 37 percent in the
Midwest and by 27 percent in the South, the report found.
"It's a big change," said Radley M. Horton, a climate scientist at
Columbia University in New York who helped write the report. He added
that scientists do not fully understand the regional variations.
In recent years, sudden intense rains have caused extensive damage.
For instance, large parts of Nashville were devastated by floods in
2010 after nearly 20 inches of rain fell in two days. [see
http://www.nytimes.com/2010/05/04/us/04flood.html ] Last year, parts
of Colorado flooded after getting as much rain in a week as normally
falls in a year.
[http://www.nytimes.com/2013/09/14/us/colorado-flooding.html ] Just
last week, widespread devastation occurred in the Florida Panhandle
from rains that may have exceeded two feet in 24 hours.[see
The new report emphasized that people should not expect global
warming to happen at a steady pace, nor at the same rate throughout
the country. Bitterly cold winters will continue to occur, the report
said, even as they become somewhat less likely. Warming, too, will
vary. While most of the country has warmed sharply over the past
century, the Southeast has barely warmed at all, and a section of
southern Alabama has even cooled slightly.
The report cited the likely role of climate change in causing an
outbreak of mountain pine beetles that has devastated millions of
acres of pine forest across the American West and the Canadian
province of British Columbia; warmer winters and longer summers have
let more of the beetles survive and reproduce at an exponential rate.
And the report warned of severe, long-lasting heat waves. For
instance, it cited research saying the type of record-breaking heat
that scorched Texas and Oklahoma in 2011 had become substantially
more likely because of the human release of greenhouse gases.[see
On rising sea levels, the new report went beyond warnings issued in
September by the United Nations Intergovernmental Panel on Climate
Change, which said that by the end of the century, sea levels could
rise by as much as three feet globally if emissions continue at a
]The American scientists said the rise could be anywhere from one to
four feet, and added that six feet could not be ruled out. Along much
of the East Coast, the situation will be worse than the global
average because the land there is sinking, the scientists said.
Historically, the United States was responsible for more emissions
than any other country. Lately, China has become the largest emitter
over all, though its emissions per person are still far below those
of the United States.
The report pointed out that while the country as a whole still had no
comprehensive climate legislation, many states and cities had begun
to take steps to limit emissions and to adapt to climatic changes
that can no longer be avoided. But the report found that these
efforts were inadequate.
"There is mounting evidence that harm to the nation will increase
substantially in the future unless global emissions of heat-trapping
gases are greatly reduced," the report warned.
SIDEBAR PHOTO: Residents of Pensacola, Fla., were ferried to safety
last month. Severe weather killed at least 38 people in eight states
in mid-April. Credit Bruce Graner/Pensacola News Journal, via
SIDEBAR Video: White House on Climate Change Report
In a video released by the White House, President Obama's science
adviser, John P. Holdren, discussed a new study on climate change.
SIDEBAR PHOTOGRAPHS: Rising Seas -- Some areas of the globe are
especially vulnerable to rising sea levels and inhabitants are being
forced to make stark changes in their lives.
Correction: May 6, 2014
An earlier version of a picture caption with this article
misidentified a town where overflow from the South Platte River in
Colorado submerged cars. It is Greeley, Colo., not Greenley.
Coral Davenport contributed reporting.
A version of this article appears in print on May 7, 2014, on page A1
of the New York edition with the headline: U.S. Climate Has Already
Changed, Study Finds, Citing Heat and Floods. Order Reprints|Today's