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500 million years of climate change Ice core data for the past 400,000 years, with the present at right. Note length of glacial cycles averages ~100,000 years. Blue curve is temperature, green curve is CO 2, and red curve is windblown glacial dust (loess). Scale: Millions of years before present, earlier dates approximate.
Climate change can also be used more broadly to include changes to the climate that have happened throughout Earth's history. [32] Global warming—used as early as 1975 [33] —became the more popular term after NASA climate scientist James Hansen used it in his 1988 testimony in the U.S. Senate. [34] Since the 2000s, climate change has ...
Some models can reproduce the 100,000-year cycles as a result of non-linear interactions between small changes in the Earth's orbit and internal oscillations of the climate system. [ 29 ] [ 30 ] In particular, the mechanism of the stochastic resonance was originally proposed in order to describe this interaction.
Throughout Earth's climate history (Paleoclimate) its climate has fluctuated between two primary states: greenhouse and icehouse Earth. [1] Both climate states last for millions of years and should not be confused with the much smaller glacial and interglacial periods, which occur as alternating phases within an icehouse period (known as an ice age) and tend to last less than one million years ...
From ancient times, people suspected that the climate of a region could change over the course of centuries. For example, Theophrastus, a pupil of Ancient Greek philosopher Aristotle in the 4th century BC, told how the draining of marshes had made a particular locality more susceptible to freezing, and speculated that lands became warmer when the clearing of forests exposed them to sunlight.
However, orbital forcing would predict maximum climate response several thousand years earlier than those observed in the Northern Hemisphere. The delay may be a result of the continuing changes in climate, as the Earth emerged from the last glacial period and related to ice–albedo feedback. Different sites often show climate changes at ...
A 2019 study found scientific consensus to be at 100%, and a 2021 study concluded that consensus exceeded 99%. Another 2021 study found that 98.7% of climate experts indicated that the Earth is getting warmer mostly because of human activity. (from History of climate change science)
Over the years, the definitions of climate variability and the related term climate change have shifted. While the term climate change now implies change that is both long-term and of human causation, in the 1960s the word climate change was used for what we now describe as climate variability, that is, climatic inconsistencies and anomalies. [28]