Climate change: How do we know? The Earth's climate has changed
throughout history. Just in the last 650,000 years there have
been seven cycles of glacial advance and retreat, with the
abrupt end of the last ice age about 7,000 years ago marking the
beginning of the modern climate era — and of human civilization.
Most of these climate changes are attributed to very small
variations in Earth’s orbit that change the amount of solar
energy our planet receives. "Scientific evidence for warming of
the climate system is unequivocal." - Intergovernmental Panel on
Climate Change The current warming trend is of particular
significance because most of it is very likely human-induced and
proceeding at a rate that is unprecedented in the past 1,300
years.1 Earth-orbiting satellites and other technological
advances have enabled scientists to see the big picture,
collecting many different types of information about our planet
and its climate on a global scale. Studying these climate data
collected over many years reveal th