Log In Register Now Help HOME PAGETODAY'S PAPERVIDEOMOST POPULARU.S. Edition
Search All NYTimes.com
Environment
WORLD U.S. N.Y. / REGION BUSINESS TECHNOLOGY SCIENCE ENVIRONMENTSPACE & COSMOSHEALTH SPORTS OPINION ARTS STYLE TRAVEL JOBS REAL ESTATE AUTOS
Advertise on NYTimes.com
Carbon Dioxide Level Passes Long-Feared Milestone
Jonathan Kingston/Aurora Select, for The New York Times
A view from the top of the Mauna Loa Observatory in Hawaii. The site has long been ground zero for monitoring the worldwide carbon dioxide trend.
By JUSTIN GILLIS
Published: May 10, 2013 357 Comments
FACEBOOK
TWITTER
GOOGLE+
SAVE
E-MAIL
SHARE
PRINT
SINGLE PAGE
REPRINTS
The level of the most important heat-trapping gas in the atmosphere, carbon dioxide, has passed a long-feared milestone, scientists reported on Friday, reaching a concentration not seen on the earth for millions of years.
Temperature Rising
Articles in this series focus on the central arguments in the climate debate and examine the evidence for global warming and its consequences.
Multimedia
Graphic
Crossing a Line
Related in Opinion
Dot Earth Blog: Milestone Nears on Curve Charting the Human Imprint on the Atmosphere (May 2, 2013)
Connect With Us on Social Media
@nytimesscience on Twitter.
Environment Reporters on Twitter
Like the science desk on Facebook.
Enlarge This Image
Jonathan Kingston/Aurora Select, for The New York Times
A plaque adorns the building dedicated to Charles David Keeling, who started measuring atmospheric carbon dioxide at the site in 1958.
Readers’ Comments
Share your thoughts.
Post a Comment »
Read All Comments (357) »
Scientific monitors reported that the gas had reached an average daily level that surpassed 400 parts per million — just an odometer moment in one sense, but also a sobering reminder that decades of efforts to bring human-produced emissions under control are faltering.
The best available evidence suggests the amount of the gas in the air has not been this high for at least three million years, before humans evolved, and scientists believe the rise portends large changes in the climate and the level of the sea.
“It symbolizes that so far we have failed miserably in tackling this problem,” said Pieter P. Tans, who runs the monitoring program at the National Oceanic and Atmospheric Administration that reported the new reading.
Ralph Keeling, who runs another monitoring program at the Scripps Institution of Oceanography in San Diego, said a continuing rise could be catastrophic. “It means we are quickly losing the possibility of keeping the climate below what people thought were possibly tolerable thresholds,” he said.
The new measurement came from analyzers high atop Mauna Loa, the volcano on the big island of Hawaii that has long been ground zero for monitoring the worldwide carbon dioxide trend.
Devices there sample clean, crisp air that has blown thousands of miles across the Pacific Ocean, producing a record of rising carbon dioxide levels that has been closely tracked for half a century.
Carbon dioxide above 400 parts per million was first seen in the Arctic last year, and had also spiked above that level in hourly readings at Mauna Loa. But the average reading for an entire day surpassed that level at Mauna Loa for the first time in the 24 hours that ended at 8 p.m. Eastern Daylight Time on Thursday, according to data from both NOAA and Scripps.
Carbon dioxide rises and falls on a seasonal cycle and the level will dip below 400 this summer, as leaf growth in the Northern Hemisphere pulls about 10 billion tons of carbon out of the air. But experts say that will be a brief reprieve — the moment is approaching when no measurement of the ambient air anywhere on earth, in any season, will produce a reading below 400.
“It feels like the inevitable march toward disaster,” said Maureen E. Raymo, a Columbia University earth scientist.
From studying air bubbles trapped in Antarctic ice, scientists know that going back 800,000 years, the carbon dioxide level oscillated in a tight band, from about 180 parts per million in the depths of ice ages, to about 280 during the warm periods between. The evidence shows that global temperatures and CO2 levels are tightly linked.
For the entire period of human civilization, roughly 8,000 years, the carbon dioxide level was relatively stable near that upper bound. But the burning of fossil fuels has caused a 41 percent increase in the heat-trapping gas since the Industrial Revolution, a mere geological instant, and scientists say the climate is beginning to react, though they expect far larger changes in the future.
Governments have been trying since 1992 to rein in emissions, but far from slowing, emissions are rising at an accelerating pace, thanks partly to rapid economic growth in developing countries. Scientists fear the level of the gas could triple or even quadruple before being brought under control.
Indirect measurements suggest that the last time the carbon dioxide level was this high was at least three million years ago, during an epoch called the Pliocene. Geological research shows that the climate then was far warmer than today, the world’s ice caps were smaller, and the sea level might have been as much as 60 or 80 feet higher.
Experts fear that humanity may be precipitating a return to such conditions — except this time, billions of people are in harm’s way.
“It takes a long time to melt ice, but we’re doing it,” Dr. Keeling said. “It’s scary.”
1 2 NEXT PAGE »
This article has been revised to reflect the following correction:
Correction: May 10, 2013
An earlier version of this article misstated the amount of carbon dioxide in the air as of Thursday’s reading from monitors. It is .04 percent, not .0004 percent.
SAVE
E-MAIL
SHARE
357 Comments
Share your thoughts.
ALLREADER PICKSNYT PICKS
Newest
Write a Comment
Get Free E-mail Alerts on These Topics
Carbon Dioxide Global Warming
Greenhouse Gas Emissions National Oceanic and Atmospheric Administration
Ads by Google what's this?
Prostate Cancer Brockton
Get a 2nd Opinion Before Making any
Prostate Cancer Treatment Decisions
ResearchProstateCancer.com/Brockton
Log In With Facebook
Log in to see what your friends are sharing on nytimes.com. Privacy Policy | What’s This?
What’s Popular Now
Cyberthieves Looted A.T.M.’s of $45 Million in Just Hours
For Office Workers, Lunchtime Dance Parties
Advertise on NYTimes.com
MOST E-MAILEDRECOMMENDED FOR YOU
4 articles in the past month
All Recommendations
1.
Iraq’s Worsening Sunni Protests Revolve Around Antiterrorism Tactics
2.
Iraq: At Least 17 People Killed in Baghdad Attacks
3.
Iran Warns Syrian Rebels After Report of Shrine Desecration
4.
Hezbollah Takes Risks by Fighting Rebels in Syria
5.
ARTSBEAT
Opponents Rally Against New York Public Library Plan
6.
A Place to Hang Out (Read, Too)
7.
CITY ROOM
At Brooklyn Library's New Center, Books Are Secondary
8.
F.B.I. Did Not Tell Police in Boston of Russian Tip
9.
Anti-Blasphemy Protests in Bangladesh Turn Violent
10.
LETTERS
When Museums Decide to Return Looted Art
Go to Your Recommendations »
What’s This? | Don’t Show
Ads by Google what's this?
2013 Best Skin Tighteners
An Unbiased Review List of The Top
Performing Skin Tighteners In 2013
www.SkinCareSearch.com/FaceLifting INSIDE NYTIMES.COM
TRAVEL »
36 Hours in Las Vegas
DANCE »
New York City Ballet Season Gala
OPINION »
Taking Note: The Latest G.O.P. Temper Tantrum
Republican senators boycotted the vote for the president’s E.P.A. nominee.
THEATER »
‘On Your Toes,’ With Christine Baranski
OPINION »
Letters: The Health Law and Its Incentives
MAGAZINE »
How Does Shonda Rhimes Keep Making Hits?
U.S. »
Citrus Disease With No Cure Is Ravaging Florida
SPORTS »
The Coach Who Stands Above Them All
ART & DESIGN »
Made for ‘Ugh,’ Appropriated for ‘Oooh’
OPINION »
Op-Ed: How to Heal Balkan Wounds for Good
Minority rights are the key to dissolving the enmity between Serbia and Kosovo.
BUSINESS »
Challenge to Dogma on Owning a Home
OPINION »
Op-Ed: The Next Pandemic Is Close
© 2013 The New York Times CompanySite MapPrivacyYour Ad ChoicesAdvertiseTerms of SaleTerms of ServiceWork With UsRSSHelpContact UsSite Feedback