Geoscience Reference
In-Depth Information
2
The Ocean and the Climate System
2.1. Introduction
Global warming, now well attested on a global scale, remains an
important subject of study since its characteristics are difficult to typify,
on account of its complexity and the inadequacy of our current
knowledge of the state of the ocean. Anticipating how the intrinsic
properties that characterize the ocean contribute to shaping the state of
the climate and its evolution remains a major challenge. After
presenting some findings concerning the changes already observed
and methods for studying future projections, we will return to the
behavior of the ocean and the way in which it could influence the
evolution of the climate by its particular dynamics and rhythm.
2.2. Climate change
The Earth has experienced greatly contrasting climates, from its
“snowball” stage, 640 million years ago when the average temperature
was about -50°C, to the very hot climate of the Cretaceous Period,
when the average temperature exceeded 20°C. More recently, the last
few million years have been marked by an alternation of ice ages
interspersed with hot interglacial periods. These variations have been
attributed to changes in the astronomic parameters that influence the
distribution of solar energy received by the Earth's surface. For the
