Climate
change is a
significant and lasting change in the statistical distribution of weather
patterns over periods ranging from decades to millions of years. It may be a
change in average weather conditions, or in the distribution of weather around
the average conditions (i.e., more or fewer extreme weather events). Climate
change is caused by factors that include oceanic processes (such as oceanic
circulation), biotic processes, variations in solar radiation received by
Earth, plate tectonics and volcanic eruptions, and human-induced alterations of
the natural world; these latter effects are currently causing global warming,
and "climate change" is often used to describe human-specific impacts.
Global
warming is the rise
in the average temperature of Earth's atmosphere and oceans since the late 19th
century and its projected continuation. Since the early 20th century, Earth's
