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Global Temperature 2005: Second Warmest since 1891

The global average surface temperature during 2005 was +0.32°C above normal (1971-2000 average), and was the second highest next only to 1998 since 1891. The annual mean temperature over the globe has increased at a rate of 0.66°C per 100 years (Figure1).

The annual mean temperature has varied in different time scales ranging from a few years to several decades. The increasing trend is likely due to human activities, particularly the emission of greenhouse gases.

At the beginning of 2006, JMA started to estimate the global mean temperature anomaly combined not only over land but also over the ocean using the JMA's original long-term sea surface temperature analysis data, called COBE-SST. Accordingly, JMA is monitoring the global warming using this combined data, instead of the land-only data. For reference, the global average surface temperature (land only) was +0.58°C above normal in 2005. It also reached the second highest record since 1880 (Figure2).

In Japan, the surface temperature during 2005 was +0.18°C above normal (1971-2000 average), and was the fourteenth highest since 1898. The mean temperature has increased at a rate of about 1.06°C per 100 years with large short-term variations (Figure3).

(Hiroko Morooka, Climate Prediction Division)

Figure 1 Annual anomalies of global average surface temperature from 1891 to 2005

The bars indicate anomalies from the climatological normal (1971-2000 average). The blue line shows five-year running mean anomalies and the red line indicates the long-term linear trend.

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Figure 2 Annual anomalies of global average surface temperature (only land) from 1880 to 2005

Same as Figure.1.

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Figure 3 Annual anomalies of average surface temperature over Japan from 1898 to 2005

Same as Figure.1. The average temperature is calculated from observational data of 17 stations (Abashiri, Nemuro, Suttsu, Yamagata, Ishinomaki, Fushiki, Nagano, Mito, Iida, Choshi, Sakai, Hamada, Hikone, Miyazaki, Tadotsu, Naze and Ishigakijima), which are considered not much influenced by urbanization and have continuous records since 1898.

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