% This file contains a brief summary of the changes in Earth's global average % surface temperature estimated by combining the Berkeley Earth land-surface % temperature field with a reinterpolated version of the HadSST ocean temperature % field. % % Two versions of this average are reported. These differ in how they treat % locations with sea ice. In the first version, temperature anomalies in the % presence of sea ice are extrapolated from land-surface air temperature anomalies. % In the second version, temperature anomalies in the presence of sea ice are % extrapolated from sea-surface water temperature anomalies (usually collected % from open water areas on the periphery of the sea ice). For most of the % ocean, sea-surface temperatures are similar to near-surface air temperatures; % however, air temperatures above sea ice can differ substantially from the water % below the sea ice. The air temperature version of this average shows larger % changes in the recent period, in part this is because water temperature changes % are limited by the freezing point of ocean water. We believe that the use of air % temperatures above sea ice provides a more natural means of describing changes in % Earth's surface temperature. % % The percent coverage of sea ice was taken from the HadISST dataset and varies % by month and location. In the typical month, between 3.5% and 5.5% of the % Earth's surface is covered with sea ice. Prior to 1900, the ice field merely % repeats a seasonal climatology and is not directly constrained by observations. % For more information on the processing and use of HadISST and HadSST refer to % the description file for the combined gridded data product. % % Temperatures are in Celsius and reported as anomalies % relative to the Jan 1951-Dec 1980 average. Uncertainties represent the 95% confidence % interval for statistical and spatial undersampling effects as well as ocean biases. % % Estimated Jan 1951-Dec 1980 global mean temperature (C) % Using air temperature above sea ice: 14.176 +/- 0.048 % Using water temperature below sea ice: 14.723 +/- 0.048 % % % Land + Ocean anomaly using air temperature above sea ice Land + Ocean using water temperature below sea ice % Year, Annual Anomaly, Annual Unc., Five-year Anomaly, Five-year Unc., Annual Anomaly, Annual Unc., Five-year Anomaly, Five-year Unc. 1850 -0.532 0.181 NaN NaN -0.482 0.161 NaN NaN 1851 -0.402 0.188 NaN NaN -0.368 0.166 NaN NaN 1852 -0.399 0.167 -0.427 0.138 -0.356 0.150 -0.386 0.122 1853 -0.426 0.158 -0.390 0.118 -0.387 0.141 -0.349 0.106 1854 -0.373 0.142 -0.404 0.105 -0.337 0.127 -0.362 0.095 1855 -0.347 0.122 -0.446 0.097 -0.298 0.112 -0.401 0.087 1856 -0.475 0.127 -0.454 0.088 -0.433 0.114 -0.409 0.081 1857 -0.608 0.131 -0.460 0.082 -0.550 0.119 -0.415 0.076 1858 -0.465 0.120 -0.484 0.086 -0.426 0.111 -0.442 0.081 1859 -0.403 0.129 -0.504 0.093 -0.369 0.119 -0.461 0.089 1860 -0.469 0.121 -0.514 0.114 -0.432 0.114 -0.468 0.107 1861 -0.575 0.160 -0.505 0.128 -0.526 0.153 -0.457 0.123 1862 -0.657 0.202 -0.515 0.133 -0.586 0.185 -0.466 0.129 1863 -0.421 0.187 -0.490 0.137 -0.375 0.182 -0.441 0.136 1864 -0.454 0.142 -0.431 0.131 -0.414 0.135 -0.385 0.132 1865 -0.342 0.157 -0.353 0.123 -0.307 0.156 -0.317 0.128 1866 -0.281 0.147 -0.322 0.116 -0.244 0.146 -0.288 0.120 1867 -0.266 0.146 -0.286 0.112 -0.245 0.146 -0.254 0.115 1868 -0.270 0.128 -0.288 0.098 -0.228 0.127 -0.258 0.100 1869 -0.270 0.119 -0.306 0.087 -0.248 0.113 -0.274 0.088 1870 -0.354 0.105 -0.322 0.077 -0.325 0.100 -0.287 0.077 1871 -0.370 0.111 -0.330 0.077 -0.324 0.104 -0.297 0.074 1872 -0.344 0.115 -0.351 0.079 -0.310 0.107 -0.320 0.075 1873 -0.312 0.128 -0.365 0.081 -0.277 0.117 -0.330 0.076 1874 -0.376 0.113 -0.378 0.081 -0.364 0.105 -0.344 0.076 1875 -0.424 0.099 -0.318 0.082 -0.376 0.092 -0.286 0.077 1876 -0.433 0.105 -0.245 0.077 -0.392 0.098 -0.219 0.073 1877 -0.046 0.106 -0.227 0.073 -0.023 0.101 -0.196 0.070 1878 0.056 0.098 -0.210 0.077 0.059 0.094 -0.181 0.072 1879 -0.289 0.092 -0.173 0.075 -0.250 0.086 -0.145 0.070 1880 -0.341 0.112 -0.226 0.071 -0.297 0.101 -0.192 0.066 1881 -0.246 0.096 -0.309 0.070 -0.215 0.087 -0.269 0.064 1882 -0.310 0.085 -0.355 0.068 -0.258 0.080 -0.310 0.063 1883 -0.359 0.089 -0.385 0.062 -0.327 0.081 -0.338 0.058 1884 -0.519 0.080 -0.442 0.059 -0.455 0.075 -0.390 0.057 1885 -0.492 0.084 -0.490 0.060 -0.437 0.081 -0.435 0.058 1886 -0.531 0.081 -0.489 0.060 -0.475 0.081 -0.432 0.058 1887 -0.549 0.087 -0.430 0.061 -0.480 0.083 -0.379 0.060 1888 -0.355 0.083 -0.434 0.063 -0.310 0.077 -0.384 0.061 1889 -0.225 0.086 -0.409 0.065 -0.190 0.084 -0.360 0.063 1890 -0.512 0.092 -0.389 0.066 -0.462 0.089 -0.346 0.064 1891 -0.405 0.093 -0.407 0.068 -0.355 0.089 -0.365 0.065 1892 -0.451 0.089 -0.448 0.068 -0.413 0.086 -0.404 0.064 1893 -0.440 0.090 -0.419 0.066 -0.403 0.084 -0.378 0.063 1894 -0.433 0.084 -0.391 0.066 -0.388 0.080 -0.349 0.062 1895 -0.367 0.089 -0.349 0.066 -0.330 0.085 -0.310 0.062 1896 -0.263 0.092 -0.350 0.065 -0.212 0.084 -0.310 0.061 1897 -0.242 0.089 -0.318 0.063 -0.218 0.086 -0.281 0.059 1898 -0.444 0.082 -0.277 0.062 -0.405 0.077 -0.245 0.059 1899 -0.273 0.078 -0.272 0.060 -0.242 0.073 -0.247 0.057 1900 -0.164 0.083 -0.300 0.058 -0.147 0.082 -0.271 0.055 1901 -0.239 0.085 -0.306 0.056 -0.222 0.080 -0.280 0.054 1902 -0.379 0.080 -0.356 0.056 -0.341 0.078 -0.330 0.055 1903 -0.476 0.077 -0.395 0.053 -0.450 0.074 -0.367 0.052 1904 -0.522 0.079 -0.406 0.052 -0.492 0.077 -0.376 0.052 1905 -0.360 0.073 -0.423 0.052 -0.333 0.071 -0.392 0.052 1906 -0.290 0.074 -0.425 0.053 -0.264 0.074 -0.395 0.052 1907 -0.469 0.079 -0.429 0.052 -0.423 0.076 -0.397 0.050 1908 -0.484 0.082 -0.460 0.053 -0.461 0.077 -0.425 0.050 1909 -0.542 0.077 -0.508 0.053 -0.501 0.069 -0.476 0.050 1910 -0.514 0.072 -0.507 0.052 -0.476 0.069 -0.476 0.049 1911 -0.529 0.071 -0.494 0.050 -0.518 0.070 -0.461 0.047 1912 -0.466 0.076 -0.436 0.049 -0.425 0.070 -0.406 0.046 1913 -0.421 0.070 -0.370 0.050 -0.386 0.066 -0.341 0.047 1914 -0.252 0.073 -0.351 0.051 -0.222 0.069 -0.316 0.048 1915 -0.184 0.078 -0.365 0.052 -0.153 0.076 -0.329 0.050 1916 -0.430 0.078 -0.359 0.054 -0.395 0.076 -0.321 0.053 1917 -0.537 0.080 -0.369 0.057 -0.487 0.078 -0.335 0.056 1918 -0.390 0.081 -0.389 0.058 -0.346 0.077 -0.359 0.056 1919 -0.305 0.082 -0.346 0.058 -0.294 0.080 -0.319 0.056 1920 -0.285 0.078 -0.300 0.055 -0.271 0.076 -0.279 0.053 1921 -0.212 0.076 -0.279 0.054 -0.196 0.072 -0.265 0.052 1922 -0.307 0.072 -0.273 0.051 -0.288 0.069 -0.258 0.049 1923 -0.286 0.070 -0.263 0.050 -0.274 0.067 -0.247 0.048 1924 -0.275 0.067 -0.240 0.049 -0.261 0.065 -0.222 0.047 1925 -0.236 0.070 -0.221 0.048 -0.215 0.067 -0.202 0.047 1926 -0.096 0.068 -0.200 0.048 -0.070 0.065 -0.181 0.046 1927 -0.209 0.065 -0.219 0.049 -0.189 0.062 -0.196 0.047 1928 -0.185 0.067 -0.201 0.049 -0.172 0.064 -0.180 0.046 1929 -0.371 0.069 -0.199 0.049 -0.337 0.066 -0.182 0.047 1930 -0.144 0.067 -0.182 0.051 -0.134 0.064 -0.169 0.047 1931 -0.084 0.070 -0.209 0.051 -0.078 0.066 -0.193 0.048 1932 -0.128 0.072 -0.170 0.052 -0.124 0.065 -0.159 0.047 1933 -0.316 0.071 -0.185 0.052 -0.293 0.066 -0.171 0.047 1934 -0.176 0.068 -0.201 0.050 -0.166 0.063 -0.184 0.046 1935 -0.220 0.066 -0.175 0.048 -0.193 0.063 -0.162 0.044 1936 -0.167 0.063 -0.110 0.046 -0.146 0.060 -0.106 0.043 1937 0.006 0.065 -0.079 0.046 -0.009 0.061 -0.073 0.043 1938 0.007 0.066 -0.020 0.046 -0.014 0.063 -0.021 0.043 1939 -0.023 0.071 0.023 0.047 -0.002 0.068 0.023 0.045 1940 0.077 0.072 0.024 0.050 0.064 0.070 0.029 0.050 1941 0.049 0.075 0.032 0.056 0.075 0.074 0.038 0.056 1942 0.009 0.084 0.065 0.061 0.019 0.085 0.066 0.062 1943 0.047 0.086 0.053 0.064 0.035 0.086 0.060 0.066 1944 0.142 0.086 0.032 0.061 0.138 0.088 0.038 0.063 1945 0.016 0.083 0.038 0.056 0.033 0.085 0.036 0.057 1946 -0.055 0.082 0.016 0.055 -0.037 0.083 0.021 0.056 1947 0.043 0.084 -0.033 0.056 0.009 0.085 -0.023 0.058 1948 -0.064 0.086 -0.071 0.060 -0.038 0.089 -0.063 0.061 1949 -0.102 0.072 -0.060 0.057 -0.082 0.072 -0.055 0.059 1950 -0.174 0.067 -0.055 0.054 -0.168 0.068 -0.045 0.055 1951 -0.003 0.064 -0.015 0.051 0.002 0.064 -0.014 0.051 1952 0.070 0.068 -0.008 0.050 0.059 0.067 -0.012 0.050 1953 0.133 0.067 0.004 0.048 0.119 0.066 -0.003 0.048 1954 -0.066 0.065 -0.031 0.046 -0.074 0.066 -0.043 0.046 1955 -0.112 0.061 -0.032 0.045 -0.124 0.061 -0.040 0.044 1956 -0.180 0.053 -0.045 0.043 -0.194 0.054 -0.047 0.042 1957 0.066 0.071 -0.025 0.042 0.072 0.063 -0.024 0.040 1958 0.065 0.056 -0.005 0.039 0.083 0.055 -0.002 0.038 1959 0.036 0.050 0.045 0.038 0.040 0.052 0.053 0.037 1960 -0.012 0.051 0.037 0.038 -0.010 0.051 0.043 0.036 1961 0.072 0.048 0.037 0.037 0.081 0.049 0.042 0.036 1962 0.026 0.057 -0.010 0.037 0.022 0.053 -0.002 0.035 1963 0.065 0.052 -0.029 0.037 0.076 0.053 -0.021 0.036 1964 -0.202 0.049 -0.050 0.037 -0.181 0.050 -0.044 0.036 1965 -0.103 0.049 -0.054 0.035 -0.102 0.051 -0.049 0.035 1966 -0.037 0.049 -0.079 0.034 -0.034 0.051 -0.073 0.034 1967 0.006 0.047 -0.020 0.032 -0.006 0.048 -0.019 0.032 1968 -0.057 0.044 0.006 0.031 -0.044 0.046 0.009 0.031 1969 0.089 0.044 -0.007 0.030 0.089 0.046 -0.003 0.030 1970 0.027 0.044 -0.010 0.030 0.041 0.045 -0.004 0.029 1971 -0.100 0.045 0.023 0.029 -0.098 0.046 0.028 0.028 1972 -0.008 0.044 -0.017 0.028 -0.008 0.045 -0.017 0.027 1973 0.109 0.040 -0.034 0.028 0.113 0.042 -0.038 0.027 1974 -0.113 0.044 -0.046 0.027 -0.134 0.043 -0.051 0.026 1975 -0.057 0.044 -0.018 0.027 -0.062 0.044 -0.026 0.026 1976 -0.162 0.044 -0.038 0.026 -0.161 0.043 -0.047 0.025 1977 0.133 0.040 0.003 0.024 0.117 0.041 0.002 0.023 1978 0.007 0.040 0.057 0.023 0.005 0.041 0.055 0.022 1979 0.096 0.032 0.141 0.023 0.114 0.032 0.131 0.022 1980 0.213 0.034 0.124 0.024 0.198 0.035 0.118 0.023 1981 0.258 0.037 0.170 0.024 0.219 0.038 0.163 0.023 1982 0.045 0.039 0.165 0.025 0.051 0.040 0.151 0.024 1983 0.238 0.039 0.134 0.025 0.231 0.039 0.121 0.024 1984 0.071 0.036 0.105 0.025 0.054 0.036 0.096 0.024 1985 0.059 0.032 0.145 0.025 0.049 0.032 0.133 0.024 1986 0.111 0.034 0.156 0.025 0.094 0.034 0.141 0.025 1987 0.246 0.034 0.177 0.026 0.237 0.034 0.161 0.026 1988 0.292 0.037 0.238 0.028 0.269 0.036 0.219 0.028 1989 0.175 0.037 0.286 0.029 0.157 0.037 0.264 0.029 1990 0.367 0.039 0.270 0.031 0.340 0.040 0.250 0.031 1991 0.351 0.040 0.250 0.032 0.317 0.041 0.232 0.033 1992 0.167 0.041 0.265 0.034 0.166 0.043 0.249 0.035 1993 0.193 0.044 0.270 0.036 0.178 0.045 0.250 0.036 1994 0.246 0.044 0.259 0.037 0.242 0.045 0.233 0.038 1995 0.393 0.046 0.313 0.037 0.346 0.047 0.283 0.038 1996 0.295 0.044 0.392 0.038 0.230 0.045 0.354 0.039 1997 0.437 0.043 0.413 0.039 0.417 0.044 0.366 0.040 1998 0.589 0.048 0.408 0.040 0.533 0.049 0.361 0.041 1999 0.353 0.048 0.451 0.041 0.306 0.049 0.409 0.042 2000 0.367 0.049 0.481 0.043 0.316 0.050 0.433 0.043 2001 0.510 0.048 0.478 0.044 0.474 0.049 0.433 0.044 2002 0.589 0.048 0.503 0.044 0.535 0.049 0.464 0.044 2003 0.573 0.050 0.561 0.044 0.533 0.050 0.519 0.044 2004 0.477 0.047 0.581 0.044 0.464 0.047 0.528 0.044 2005 0.659 0.047 0.587 0.044 0.589 0.048 0.528 0.044 2006 0.610 0.046 0.570 0.043 0.521 0.047 0.508 0.043 2007 0.618 0.047 0.598 0.044 0.534 0.046 0.524 0.043 2008 0.485 0.047 0.604 0.044 0.431 0.045 0.527 0.043 2009 0.618 0.048 0.597 0.044 0.545 0.047 0.519 0.043 2010 0.690 0.046 0.590 0.043 0.606 0.047 0.515 0.043 2011 0.573 0.046 0.616 0.042 0.482 0.046 0.542 0.043 2012 0.587 0.044 0.627 0.042 0.512 0.045 0.557 0.043 2013 0.612 0.045 0.653 0.042 0.565 0.047 0.589 0.043 2014 0.675 0.047 0.728 0.042 0.618 0.048 0.660 0.043 2015 0.816 0.045 0.778 0.042 0.767 0.046 0.706 0.043 2016 0.951 0.045 0.810 0.042 0.837 0.047 0.726 0.043 2017 0.837 0.045 NaN NaN 0.744 0.047 NaN NaN 2018 0.769 0.045 NaN NaN 0.664 0.045 NaN NaN