Changes

As far back as temperature records can be reconstructed, periods of global warming and global cooling have alternated; see [[ice age]]s and [[interglacial warming]].

As far back as temperature records can be reconstructed, periods of global warming and global cooling have alternated; see [[ice age]]s and [[interglacial warming]].

In the  modern period of global warming, a slight increase of {{temperature|0.8|1.4}} has been measured at weather stations throughout the world, since around 1850, when organized records began to be kept. Since this happens to correlate with increases in [[carbon dioxide]], it's natural to speculate about what sort of cause and effect relationship they may have.

In the  modern period of global warming, a slight increase of {{temperature|0.8|1.4}} has been measured at weather stations throughout the world, since around 1850, when organized records began to be kept. Since this happens to correlate with increases in [[carbon dioxide]], many have speculated about their possible relationship.

==Controversy==

==Controversy==