The most general definition of climate change is a change in the statistical
properties (principally its mean and spread) of the climate system when
considered over long periods of time, regardless of cause. Accordingly,
fluctuations over periods shorter than a few decades, such as El Niño, do not
represent climate change.The term "climate change" is often used to refer specifically to anthropogenic
climate change (also known as global warming). Anthropogenic climate change
is caused by human activity, as opposed to changes in climate that may have
resulted as part of Earth's natural processes. In this sense, especially
in the context of environmental policy, the term climate change has become
synonymous with anthropogenic global warming. Within scientific journals,
global warming refers to surface temperature increases while climate change
includes global warming and everything else that increasing greenhouse gas
levels affect.A related term is "climatic change". In 1966, the World Meteorological
Organization (WMO) proposed the term "climatic change" to encompass all forms
of climatic variability on time-scales longer than 10 years, regardless of
cause. Change was a given and climatic was used as an adjective to describe
this kind of change (as opposed to political or economic change). When it
was realized that human activities had a potential to drastically alter
the climate, the term climate change replaced climatic change as the
dominant term to reflect an anthropogenic cause. Climate change was
incorporated in the title of the Intergovernmental Panel on Climate Change
(IPCC) and the UN Framework Convention on Climate Change (UNFCCC).
Climate change, used as a noun, became an issue rather than the technical
description of changing weather.