Skip to main content

Main menu

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
    • Front Matter Portal
    • Journal Club
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses
  • Submit
  • Submit
  • About
    • Editorial Board
    • PNAS Staff
    • FAQ
    • Accessibility Statement
    • Rights and Permissions
    • Site Map
  • Contact
  • Journal Club
  • Subscribe
    • Subscription Rates
    • Subscriptions FAQ
    • Open Access
    • Recommend PNAS to Your Librarian

User menu

  • Log in
  • My Cart

Search

  • Advanced search
Home
Home
  • Log in
  • My Cart

Advanced Search

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
    • Front Matter Portal
    • Journal Club
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses
  • Submit
Letter

Inferring the anthropogenic contribution to local temperature extremes

Dáithí A. Stone, Christopher J. Paciorek, Prabhat, Pardeep Pall, and Michael Wehner
  1. aComputational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
  2. bDepartment of Statistics, University of California, Berkeley, CA 94720

See allHide authors and affiliations

PNAS April 23, 2013 110 (17) E1543; https://doi.org/10.1073/pnas.1221461110
Dáithí A. Stone
aComputational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: dstone@lbl.gov
Christopher J. Paciorek
bDepartment of Statistics, University of California, Berkeley, CA 94720
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Prabhat
aComputational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Pardeep Pall
aComputational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Michael Wehner
aComputational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & SI
  • Info & Metrics
  • PDF
Loading

In PNAS, Hansen et al. (1) document an observed planet-wide increase in the frequency of extremely hot months and a decrease in the frequency of extremely cold months, consistent with earlier studies (2). This analysis is achieved through aggregation of gridded monthly temperature measurements from all over the planet. Such aggregation is advantageous in achieving statistical sampling power; however, it sacrifices regional specificity. In that light, we find the conclusion of Hansen et al. (1) that “the extreme summer climate anomalies in Texas in 2011, in Moscow in 2010, and in France in 2003 almost certainly would not have occurred in the absence of global warming” to be unsubstantiated by their analysis.

Observations show different areas of the planet warming at different rates, in line with projections from computer models (3). This effect is noticeable in the frequency distributions shown by Hansen et al. (1), in which the spread of the aggregated values increases in recent decades. Hansen et al. also include maps that show the local data feeding their global analysis. Noticeably, Moscow and Texas stand out as areas exhibiting little anomalously warm activity during recent years, barring the single summers of 2010 and 2011, respectively. In contrast, France does appear to be experiencing anomalously warm summers recently.

To quantify local changes in high temperature extremes, we apply extreme value theory methods to the same GISTEMP (Goddard Institute for Space Studies surface temperature analysis) data used by Hansen et al. (1) for the summer months of 1950–2009 (June-July-August in the north and December-January-February in the south) by fitting a time-varying extreme value distribution to the tails of the local frequency distributions (4). A field significance test of our analyses confirms the assertion by Hansen et al. (1) that changes in extreme summer temperatures are globally significant at the P < 0.002 level. Fig. 1 shows z-scores (estimated changes divided by their standard errors) for the differences between the expected 60-y maximum summer mean temperature in the 2009 and 1950 climate states. Results are consistent with Hansen et al. (1). There is no indication of increasingly hot summers near Moscow, and Texas exhibits larger but spatially incoherent changes. On the other hand, France does show large positive changes. Changes near Texas and Moscow are increased if the 2010 and 2011 years are included, but that uses the observation of an event’s occurrence as evidence of its cause; the results for France are insensitive to the inclusion of 2003.

Fig. 1.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 1.

The z-scores (estimated changes divided by their SEs) for the differences between the expected 60-y maximum summer mean temperature in the 2009 and 1950 era climate states in France (Left), Texas (Center), and regions surrounding Moscow (Right).

This analysis is far from definitive, lacking, for example, a physically based counterfactual world. We feel that more defensible analyses than presented by either Hansen et al. (1) or us in this letter are necessary to claim causal evidence between individual regional extreme events and anthropogenic changes to the climate system (5).

Footnotes

  • ↵1To whom correspondence should be addressed. E-mail: dstone{at}lbl.gov.
  • Author contributions: D.A.S., P.P., and M.W. designed research; C.J.P. and P. contributed new analysis tools; C.J.P. analyzed data; and D.A.S. and M.W. wrote the paper.

  • The authors declare no conflict of interest.

References

  1. ↵
    1. Hansen J,
    2. Sato M,
    3. Ruedy R
    (2012) Perception of climate change. Proc Natl Acad Sci USA 109(37):E2415–E2423.
    OpenUrlAbstract/FREE Full Text
  2. ↵
    1. Field CB,
    2. et al.
    1. Seneviratne SI,
    2. et al.
    (2012) in Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation, Changes in climate extremes and their impacts on the natural physical environment, ed Field CB, et al. (Cambridge Univ Press, Cambridge, UK), pp 109–230.
  3. ↵
    1. Solomon S,
    2. et al.
    1. Hegerl GC,
    2. et al.
    (2007) in Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Understanding and attributing climate change, ed Solomon S, et al. (Cambridge Univ Press, Cambridge, UK), pp 663–745.
  4. ↵
    1. Coles S
    (2001) An Introduction to Statistical Modeling of Extreme Values (Springer, London).
  5. ↵
    1. Asrar GR,
    2. Hurrell JW
    1. Stott PA,
    2. et al.
    (2013) in Climate Science for Serving Society: Research, Modelling and Prediction Priorities, Attribution of weather and climate-related events, eds Asrar GR, Hurrell JW (Springer), in press.
PreviousNext
Back to top
Article Alerts
Email Article

Thank you for your interest in spreading the word on PNAS.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Inferring the anthropogenic contribution to local temperature extremes
(Your Name) has sent you a message from PNAS
(Your Name) thought you would like to see the PNAS web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Human contribution to local temperature extremes
Dáithí A. Stone, Christopher J. Paciorek, Prabhat, Pardeep Pall, Michael Wehner
Proceedings of the National Academy of Sciences Apr 2013, 110 (17) E1543; DOI: 10.1073/pnas.1221461110

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Request Permissions
Share
Human contribution to local temperature extremes
Dáithí A. Stone, Christopher J. Paciorek, Prabhat, Pardeep Pall, Michael Wehner
Proceedings of the National Academy of Sciences Apr 2013, 110 (17) E1543; DOI: 10.1073/pnas.1221461110
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Mendeley logo Mendeley

Article Classifications

  • Physical Sciences
  • Earth, Atmospheric, and Planetary Sciences

This Letter has a Reply and related content. Please see:

  • Relationship between Letter and Reply - March 19, 2013
  • Perception of climate change - August 06, 2012
  • Perception of climate change - August 06, 2012
Proceedings of the National Academy of Sciences: 110 (17)
Table of Contents

Submit

Sign up for Article Alerts

Jump to section

  • Article
    • Footnotes
    • References
  • Figures & SI
  • Info & Metrics
  • PDF

You May Also be Interested in

Water from a faucet fills a glass.
News Feature: How “forever chemicals” might impair the immune system
Researchers are exploring whether these ubiquitous fluorinated molecules might worsen infections or hamper vaccine effectiveness.
Image credit: Shutterstock/Dmitry Naumov.
Reflection of clouds in the still waters of Mono Lake in California.
Inner Workings: Making headway with the mysteries of life’s origins
Recent experiments and simulations are starting to answer some fundamental questions about how life came to be.
Image credit: Shutterstock/Radoslaw Lecyk.
Cave in coastal Kenya with tree growing in the middle.
Journal Club: Small, sharp blades mark shift from Middle to Later Stone Age in coastal Kenya
Archaeologists have long tried to define the transition between the two time periods.
Image credit: Ceri Shipton.
Illustration of groups of people chatting
Exploring the length of human conversations
Adam Mastroianni and Daniel Gilbert explore why conversations almost never end when people want them to.
Listen
Past PodcastsSubscribe
Panda bear hanging in a tree
How horse manure helps giant pandas tolerate cold
A study finds that giant pandas roll in horse manure to increase their cold tolerance.
Image credit: Fuwen Wei.

Similar Articles

Site Logo
Powered by HighWire
  • Submit Manuscript
  • Twitter
  • Facebook
  • RSS Feeds
  • Email Alerts

Articles

  • Current Issue
  • Special Feature Articles – Most Recent
  • List of Issues

PNAS Portals

  • Anthropology
  • Chemistry
  • Classics
  • Front Matter
  • Physics
  • Sustainability Science
  • Teaching Resources

Information

  • Authors
  • Editorial Board
  • Reviewers
  • Subscribers
  • Librarians
  • Press
  • Cozzarelli Prize
  • Site Map
  • PNAS Updates
  • FAQs
  • Accessibility Statement
  • Rights & Permissions
  • About
  • Contact

Feedback    Privacy/Legal

Copyright © 2021 National Academy of Sciences. Online ISSN 1091-6490