Earth's natural climate system is complex web of interactions between land, ocean, and atmosphere. While our climate undergoes natural variations on various timescales, decades of research using paleoclimate archives, modern observations, and computer models of our climate has led to the conclusion that Earth's climate is warming as a result of human activity.

The most recent report of the Intergovernmental Panel on Climate Change determined that the earth will continue to warm at a rate of 0.1 degree per decade even if our greenhouse gas emissions are immediately stabilized at year 2000 levels. Understanding how this warming will manifest itself in different regions around the world is critical for developing effective mitigation and adaptation strategies. The Climate: Past, Present, and Future group therefore aims to better understand the behavior of the physical climate system on both global and regional scales.

The members of this working group include paleoclimatolgists, climate modelers, geologists, and oceanographers.