Global temperature change and its uncertainties since 1861

We present the first analysis of global and hemispheric surface warming trends that attempts to quantify the major sources of uncertainty. We calculate global and hemispheric annual temperature anomalies by combining land surface air temperature and sea surface temperature (SST) through an optimal averaging technique. The technique allows estimation of uncertainties in the annual anomalies resulting from data gaps and random errors. We add independent uncertainties due to urbanisation, changing land‐based observing practices and SST bias corrections. We test the accuracy of the SST bias corrections, which represent the largest source of uncertainty in the data, through a suite of climate model simulations. These indicate that the corrections are likely to be fairly accurate on an annual average and on large space scales. Allowing for serial correlation and annual uncertainties, the best linear fit to annual global surface temperature gives an increase of 0.61±0.16°C between 1861 and 2000.


Suggested citation or credit:

Folland, C. K., et al. (2001), Global temperature change and its uncertainties since 1861, Geophys. Res. Lett., 28(13), 2621–2624, doi:10.1029/2001GL012877


Additional credits:

N. A. Rayner (Met Office, Hadley Centre)

S. J. Brown (Met Office, Hadley Centre)

T. M. Smith (National Climatic Data Center)

S. S. P. Shen (Dept. Mathematical Sciences,  Univ. Alberta)

D. E. Parker (Met Office, Hadley Centre)

I. Macadam (Met Office, Hadley Centre)

P. D. Jones (Climatic Research Unit, Univ. East Anglia)

R. N. Jones (Commonwealth Sci. and Indust. Res. Org)

N. Nicholls (Bureau of Meteorology Research Centre)

D. M. H. Sexton (Met Office, Hadley Centre)


Source: Geophysical Research Letters

Publication Date: April 2001

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