<P> The instrumental temperature record provides the temperature of Earth's climate system from the historical network of in situ measurements of surface air temperatures and ocean surface temperatures . Data are collected at thousands of meteorological stations, buoys and ships around the globe . The longest - running temperature record is the Central England temperature data series, that starts in 1659 . The longest - running quasi-global record starts in 1850 . In recent decades more extensive sampling of ocean temperatures at various depths have begun allowing estimates of ocean heat content but these do not form part of the global surface temperature datasets . </P> <P> The global average and combined land and ocean surface temperature, show a warming of 0.85 (0.65 to 1.06) ° C, in the period 1880 to 2012, based on multiple independently produced datasets . This gives a trend of 0.064 ± 0.015 ° C per decade over that period . The trend is faster for land than ocean, faster for Arctic regions, and faster since the 1970s than the longer period . </P>

Where does the past 150 years of instrumental climate data come from