Past decade hottest on record, NOAA study says.
Christine Dell'Amore National Geographic News 28 Jul 10;
"Global warming is undeniable," and it's happening fast, a new U.S. government report says.
An in-depth analysis of ten climate indicators all point to a marked warming over the past three decades, with the most recent decade being the hottest on record, according to the latest of the U.S. National Atmospheric and Oceanic Administration's annual "State of the Climate" reports, which was released Wednesday. Reliable global climate record-keeping began in the 1880s.
The report focused on climate changes measured in 2009 in the context of newly available data on long-term developments.
(See "Heat Wave: 2010 to Be One of Hottest Years on Record.") For instance, surface air temperatures recorded from more than 7,000 weather stations around the world over the past few decades confirm an "unmistakable upward trend," the study says.
And for the first time, scientists put data from climate indicators—such as ocean temperature and sea-ice cover—together in one place. Their consistency "jumps off the page at you," report co-author Derek Arndt said.
"This is like going to the doctor and getting your respiratory test and circulatory test and your neurosystem test," said Arndt, head of the Climate Monitoring Branch of NOAA's National Climatic Data Center.
"It's testing all the parts, and they're all in agreement that the same thing's going on."
Global Warming Sparked Extreme Weather in 2009?
Three hundred scientists analyzed data on 37 climate indicators, but homed in on 10 that the study says are especially revealing.
Those indicators include:
* humidity,
* sea-surface temperature,
* sea ice cover,
* snow cover,
* ocean heat content,
* glacier cover,
* air temperature in the lower atmosphere,
* sea level,
* temperature over land,
* and temperature over oceans.
As scientists would predict in a hotter world, some of the indicators—such as ocean heat content and temperature over land—are increasing. Others, such as sea ice cover and snow cover, are decreasing.
The influx of greenhouses gases into the atmosphere has also hit oceans particularly hard, the NOAA report says. (See an interactive on the greenhouse effect and global warming.)
New evidence suggests that more than 90 percent of that heat trapped by greenhouses gases over the past 50 years has been absorbed into the oceans.
Because water expands as it warms, the added ocean heat is contributing to sea level rise as well as to the rapid melting of Arctic summer sea ice. That melting in 2010 is on track to be worse than 2007, when Arctic ice cover reached its lowest point on record.
Such climatic shifts are already ushering in extreme weather, which plagued much of the globe in 2009, according to the report. (See a world map of potential global warming impacts.) For instance, Australia experienced its third hottest year on record.
On one February 2009 day—labeled "Black Saturday"—in Australia, 400 wildfires swept across the state of Victoria, killing 173 people and destroying 3,500 buildings. (See pictures of the Australian fires.)
NOAA Climate Report Offers Real-World Data
The NOAA report—published in the Bulletin of the American Meteorological Society—is different from other climate publications, because it's based on observed data, not computer models, making it the "climate system's annual scorecard," the authors wrote. (Test your global warming knowledge.)
"It's telling us what's going on in the real world, rather than the imaginary world," said Kevin Trenberth, a senior scientist at the Boulder, Colorado-based National Center for Atmospheric Research.
Even so, the report "does not carry the authority of the IPCC [Intergovernmental Panel on Climate Change] by any means," Trenberth noted.
That's partially because IPCC reports—the latest of which came out in 2007 with a similar claim that warming is "unequivocal"—are produced on longer time scales, with more time for review.
And even with real-world data, "the theory with regard to global warming is still incomplete"—especially since the atmosphere is so complex, Trenberth cautioned.
This "can be seen at a glance," for example, "by looking out of the window at the wondrous, great variety in clouds."
Ten key indicators show global warming "undeniable"
Deborah Zabarenko, Reuters 29 Jul 10;
WASHINGTON (Reuters) - Melting glaciers, more humid air and eight other key indicators show that global warming is undeniable, scientists said on Wednesday, citing a new comprehensive review of the last decade of climate data.
Without addressing why this is happening, the researchers said there was no doubt that every decade on Earth since the 1980s has been hotter than the previous one, and that the planet has been warming for the last half-century.
This confirms the findings of the U.N. Intergovernmental Panel on Climate Change, which reported in 2007 with 90 percent certainty that climate change is occurring. The IPCC also said that human activities contribute to this phenomenon.
The new report was released after U.S. Senate Democrats delayed any possible legislation to curb climate change until September at the earliest. Prospects for U.S. climate change legislation this year are considered slim.
Released by the U.S. National Oceanic and Atmospheric Administration as "The 2009 State of the Climate Report," the new report draws on the work of 303 scientists from 48 countries, including data from last year.
The 10 key planet-wide indicators of a warming climate identified by the report are:
-- Higher temperatures over land
-- Higher temperatures over oceans
-- Higher ocean heat content
-- Higher near-surface air temperatures (temperatures in the troposphere, where Earth's weather occurs)
-- Higher humidity
-- Higher sea surface temperatures
-- Higher sea levels
-- Less sea ice
-- Less snow cover
-- Shrinking glaciers
The seven indicators expected to rise in a warming world rose over the last decade, the report said; the three indicators expected to decline did so over that same period.
With an almost daily flood of data on climate change, Peter Thorne of the Cooperative Institute for Climate and Satellites in Asheville, North Carolina, saw the need for a comprehensive look at the information to pick the most obvious signs of planetary warming.
"These are indicators from the top of the atmosphere to the bottom of the ocean that we would expect to be changing in a warming world," Thorne said at a telephone briefing for reporters.
"Each indicator is changing as we would expect if the world truly were warming," he said. "Not a single analysis disagrees that the global climate is changing. The bottom line conclusion that the world's been warming is simply undeniable."
The entire report can be seen online here http://www.ncdc.noaa.gov/bams-state-of-the-climate/2009.php
The report is being published in the Bulletin of the American Meteorological Society.
(Editing by Eric Walsh)
Scientists say global warming is continuing
Randolph E. Schmid, Associated Press 28 Jul 10;
WASHINGTON – Scientists from around the world are providing even more evidence of global warming, one day after President Barack Obama renewed his call for climate legislation.
"A comprehensive review of key climate indicators confirms the world is warming and the past decade was the warmest on record," the annual State of the Climate report declares.
Compiled by more than 300 scientists from 48 countries, the report said its analysis of 10 indicators that are "clearly and directly related to surface temperatures, all tell the same story: Global warming is undeniable."
Concern about rising temperatures has been growing in recent years as atmospheric scientists report rising temperatures associated with greenhouse gases released into the air by industrial and other human processes. At the same time, some skeptics have questioned the conclusions.
The new report, the 20th in a series, focuses only on global warming and does not specify a cause.
"The evidence in this report would say unequivocally yes, there is no doubt," that the Earth is warming, said Tom Karl, the transitional director of the planned NOAA Climate Service.
Deke Arndt, chief of the Climate Monitoring Branch at the National Climatic Data Center, noted that the 1980s was the warmest decade up to that point, but each year in the 1990s was warmer than the '80s average.
That makes the '90s the warmest decade, he said.
But each year in the 2000s has been warmer than the '90s average, so the first 10 years of the 2000s is now the warmest decade on record.
The new report noted that continuing warming will threaten coastal cities, infrastructure, water supply, health and agriculture.
"At first glance, the amount of increase each decade — about a fifth of a degree Fahrenheit — may seem small," the report said.
"But," it adds, "the temperature increase of about 1 degree Fahrenheit experienced during the past 50 years has already altered the planet. Glaciers and sea ice are melting, heavy rainfall is intensifying and heat waves are becoming more common and more intense."
Last month was the warmest June on record and this year has had the warmest average temperature for January-June since record keeping began, NOAA reported last week.
And a study by Princeton University researchers released Monday suggested that continued warming could cause as many as 6.7 million more Mexicans to move to the United States because of drought affecting crops in their country.
The new climate report, released by the National Oceanic and Atmospheric Administration and published as a supplement to the Bulletin of the American Meteorological Society, focused on 10 indicators of a warming world, seven which are increasing and three declining.
Rising over decades are average air temperature, the ratio of water vapor to air, ocean heat content, sea surface temperature, sea level, air temperature over the ocean and air temperature over land.
Indicators that are declining are snow cover, glaciers and sea ice.
The 10 were selected "because they were the most obviously related indicators of global temperature," explained Peter Thorne of the Cooperative Institute for Climate and Satellites, who helped develop the list when at the British weather service, known as the Met Office.
"What this data is doing is, it is screaming that the world is warming," Thorne concluded.
