The annual cycle of extra-tropical surface air temperature is an important component of the Earth's climate system. Over the past decades, a reduced amplitude of this mode has been observed in some regions. Although attributed to anthropogenic forcing, it remains unclear when dampening of the annual cycle started. Here we use a residual series of tree-ring width and maximum latewood density from the Tibetan Plateau >4,000 m asl to reconstruct changes in temperature seasonality over the past three centuries. The new proxy evidence suggests that the onset of a decrease in summer-to-winter temperature difference over the Tibetan Plateau occurred in the 1870s. Our results imply that the influence of anthropogenic forcing on temperature seasonality might have started in the late nineteenth century, and that future human influence may further contribute to a weakening of the annual temperature cycle, with subsequent effects on ecosystem functioning and productivity.

Centre of International Development and Environmental Research Justus Liebig University of Giessen 35390 Giessen Germany

Chinese Academy of Meteorological Sciences 100081 Beijing China

Department of Geography Johannes Gutenberg University 55099 Mainz Germany

Department of Geography Justus Liebig University of Giessen 35390 Giessen Germany

Global Change Research Centre and Masaryk University 61300 Brno Czech Republic

Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China

National Climate Center China Meteorological Administration 100081 Beijing China

Oeschger Centre for Climate Change Research CH 3012 Bern Switzerland

State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences 100093 Beijing China

Swiss Federal Research Institute WSL 8903 Birmensdorf Switzerland

Zobrazit více v PubMed

Stine A. R., Huybers P. & Fung I. Y. Changes in the phase of the annual cycle of surface temperature. Nature 457, 435–440 (2009). PubMed

Thomson D. J. The seasons, global temperature, and precession. Science 268, 59–68 (1995). PubMed

Qian C. & Zhang X. B. Human influences on changes in the temperature seasonality in mid- to high-latitude land areas. J. Climate 28, 5908–5921 (2015).

Stine A. R. & Huybers P. Changes in the seasonal cycle of temperature and atmospheric circulation. J. Climate 25, 7362–7380 (2012).

Li Y., Huang Y., Bergelson J., Nordborg M. & Borevitz J. O. Association mapping of local climate-sensitive quantitative trait loci in Arabidopsis thaliana. Proc. Natl Acad. Sci. USA 197, 201007431 (2010). PubMed PMC

Porter W. P., Budaraju S., Stewart W. E. & Ramankutty N. Calculating climate effects on birds and mammals: impacts on biodiversity, conservation, population parameters, and global community structure. Am. Zool. 40, 597–630 (2000).

Vasseur D. A. et al.. Increased temperature variation poses a greater risk to species than climate warming. Proc. R. Soc. B 281, 20132612 (2014). PubMed PMC

Wang G. & Dillon M. E. Recent geographic convergence in diurnal and annual temperature cycling flattens global thermal profiles. Nat. Clim. Change 4, 988–992 (2014).

Mann M. E. & Park J. Greenhouse warming and changes in the seasonal cycle of temperature: Model versus observations. Geophys. Res. Lett. 23, 1111–1114 (1996).

Wallace C. J. & Osborn T. J. Recent and future modulation of the annual cycle. Climate Res. 22, 1–11 (2002).

Qiu J. China: the third pole. Nat. News 454, 393–396 (2008). PubMed

Yao T. D. et al.. Different glacier status with atmospheric circulations in Tibetan Plateau and surroundings. Nat. Clim. Change 2, 663–667 (2012).

Duan J. P., Li L. & Fang Y. J. Seasonal spatial heterogeneity of warming rates on the Tibetan Plateau over the past 30 years. Sci. Rep. 5, 11725 (2015). PubMed PMC

Zhu H. F., Fang X. Q., Shao X. M. & Yin Z. Y. Tree ring-based February-April temperature reconstruction for Changbai Mountain in Northeast China and its implication for East Asian winter monsoon. Clim. Past 5, 661–666 (2009).

Shi J. F. et al.. Tree-ring based winter temperature reconstruction for the lower reaches of the Yangtze River in southeast China. Clim. Res. 41, 169–175 (2010).

Duan J. P., Zhang Q. B., Lv L. X. & Zhang C. Regional-scale winter-spring temperature variability and chilling damage dynamics over the past two centuries in southeastern China. Clim. Dynam. 39, 919–928 (2012).

Duan J. P., Zhang Q. B. & Lv L. X. Increased variability in cold-season temperature since the 1930s in subtropical China. J. Climate 26, 4749–4757 (2013).

Shao X. M. & Fan J. M. Past climate on west Sichuan Plateau as reconstructed from ring-widths of dragon spruce (in Chinese). Quat. Sci. 1, 81–89 (1999).

Huang K. C., Xing P. & Duan J. P. Winter season temperature variation reconstructed from tree rings over the past 394 years in Qamdo of Tibet (in Chinese). J. Earth Environ. 3, 915–922 (2012).

Zhang R. B. et al.. Dendroclimatic reconstruction of autumn–winter mean minimum temperature in the eastern Tibetan Plateau since 1600 AD. Dendrochronologia 33, 1–7 (2015).

Pederson N., Cook E. R., Jacoby G. C., Peteet D. M. & Griffin K. L. The influence of winter temperatures on the annual radial growth of six northern range margin tree species. Dendrochronologia 22, 7–29 (2004).

Brauning A. & Mantwill B. Summer temperature and summer monsoon history on the Tibetan plateau during the last 400 years recorded by tree rings. Geophys. Res. Lett. 31, L24205 (2004).

Fan Z. X., Brauning A., Yang B. & Cao K. F. Tree ring density-based summer temperature reconstruction for the central Hengduan Mountains in southern China. Global Planet Change 65, 1–11 (2009).

Wang L., Duan J. P., Chen J., Huang L. & Shao X. M. Temperature reconstruction from tree-ring maximum density of Balfour spruce in eastern Tibet, China. Int. J. Climatol. 30, 972–979 (2010).

Duan J. P. & Zhang Q. B. A 449 year warm season temperature reconstruction in the southeastern Tibetan Plateau and its relation to solar activity. J. Geophys. Res. 119, 11578–11592 (2014).

Körner C. A re-assessment of high elevation treeline positions and their explanation. Oecologia 115, 445–459 (1998). PubMed

Peterson D. W. & Peterson D. L. Mountain hemlock growth responds to climatic variability at annual and decadal time scales. Ecology 82, 3330–3345 (2001).

Gedalof Z. & Smith D. J. Dendroclimatic response of mountain hemlock (Tsuga mertensiana) in Pacific North America. Can. J. Forest Res. 31, 322–332 (2001).

Peterson D. W., Peterson D. L. & Ettl G. J. Growth responses of subalpine fir to climatic variability in the Pacific Northwest. Can. J. Forest. Res. 32, 1503–1517 (2002).

Meko D. M., Touchan R. & Anchukaitis K. J. Seascorr: a MATLAB program for identifying the seasonal climate signal in an annual tree-ring time series. Comput. Geosci. 37, 1234–1241 (2011).

Wigley T. M. L., Briffa K. R. & Jones P. D. On the average value of correlated time-series, with applications in dendroclimatology and hydrometeorology. J. Clim. Appl. Meteorol. 23, 201–213 (1984).

Michaelsen J. Cross-validation in statistical climate forecast models. J. Clim. Appl. Meteorol. 26, 1589–1600 (1987).

Rodionov S. N. A sequential algorithm for testing climate regime shifts. Geophys. Res. Lett. 31, L09204 (2004).

Rangwala I., Miller J. R. & Xu M. Warming in the Tibetan Plateau: possible influences of the changes in surface water vapor. Geophys. Res. Lett. 36, L06703 (2009).

Hegerl G. et al.. Influence of human and natural forcing on European seasonal temperatures. Nat. Geosci. 4, 99–103 (2011).

Duan K. Q., Thompson L. G., Yao T., Davis M. E. & Mosley-Thompson E. A 1000 year history of atmospheric sulfate concentrations in southern Asia as recorded by a Himalayan ice core. Geophys. Res. Lett. 34, L01810 (2007).

Stine A. R. & Huybers P. Arctic tree rings as recorders of variations in light availability. Nat Commun 5, 3836 (2014). PubMed PMC

Hunter D. E., Schwartz S. E., Wagener R. & Benkovitz C. M. Seasonal, latitudinal, and secular variations in temperature trend - evidence for influence of anthropogenic sulfate. Geophys. Res. Lett. 20, 2455–2458 (1993).

Fischer H., Wagenbach D. & Kipfstuhl J. Sulfate and nitrate firn concentrations on the Greenland ice sheet - 2. Temporal anthropogenic deposition changes. J. Geophys. Res. 103, 21935–21942 (1998).

Mayewski P. A. et al.. Greenland ice core ‘signal' characteristics: an expanded view of climate change. J. Geophys. Res. 98, 12839–12847 (1993).

Schweingruber F. H., Bartholin T., Schar E. & Briffa K. R. Radiodensitometric-dendroclimatological conifer chronologies from Lapland (Scandinavia) and the Alps (Switzerland). Boreas 17, 559–566 (1988).

Melvin T. M. & Briffa K. R. CRUST: Software for the implementation of Regional Chronology Standardisation: Part 1. Signal-Free RCS. Dendrochronologia 32, 7–20 (2014).

Cook E. R. & Krusic P. J. ARSTAN-A Tree-Ring Standardization Program Based on Detrending and Autoregressive Time Series Modeling, with Interactive Graphics (Tree-Ring Laboratory, Lamont Doherty Earth Observatory of Columbia University, 2005).

Melvin T. M. & Briffa K. R. A ‘signal-free' approach to dendroclimatic standardisation. Dendrochronologia 26, 71–86 (2008).

Jones P. D. et al.. Hemispheric and large-scale land-surface air temperature variations: an extensive revision and an update to 2010. J. Geophys. Res. 117, D05127 (2012).

Cook E. R. & Kairiukstis L. A. Methods of Dendrochronology: Applications in the Environmental Sciences (Kluwer Academic, Dordrecht, The Netherlands, 1990).

Plants in the UK flower a month earlier under recent warming