The figure shows the combined land-surface air and sea surface temperatures (in oC) 1861 to 1998, relative to the average temperature between 1961 and 1990.The mean global surface temperature has increased by about 0.3 to 0.6°C since the late 19th century and by about 0.2 to 0.3°C over the last 40 years, which is the period with most reliable data. Recent years have been among the warmest since 1860 - the period for which instrumental records are available. Warming is evident in both sea surface and land-based surface air temperatures. The warming has not been globally uniform. The recent warming has been greatest between 40°N and 70°N latitude, though some areas such as the North Atlantic Ocean have cooled in the recent decades.
Source: http://www.grida.no/climate/vital/17.htm


Precipitation has increased over land at high latitudes of the Northern Hemisphere, especially during the cold season. Decrease in precipitation occurred in steps after the 1960s over the subtropics and the tropics from Africa to Indonesia. These changes are consistent with available data analyses of changes in stream flow, lake levels and soil surface. Precipitation averaged over the earth’s land surface increased from the start of the 20th century up to about 1960, but has decreased since about 1980. There is a lack of data on precipitation over the oceans.
Source: http://www.grida.no/climate/vital/18.htm


Over the last 100 years, the global sea level has risen by about 10 to 25 cm. It is likely that much of the rise in sea level has been related to the concurrent rise in global temperature over the last 100 years. On this time scale, the warming and the consequent thermal expansion of the oceans may account for about 2-7 cm of the observed sea level rise, while the observed retreat of glaciers and ice caps may account for about 2-5 cm. The rate of observed sea level rise suggests that there has been a net positive contribution from the huge ice sheets of Greenland and Antarctica, but observations of the ice sheets do not yet allow meaningful quantitative estimates of their separate contributions. The ice sheets remain a major source of uncertainty in accounting for past changes in sea level because of insufficient data about these ice sheets.
Source: http://www.grida.no/climate/vital/19.htm