Bad Astronomy and Universe Today Forum - View Single Post - Is Solar Magnetic Field Change Modulation of Clouds ATM?

William · #5 (**permalink**) 24-October-2008, 02:31 PM

Have there been warming periods in the past? Yes.

The planet shows peculiar regular changes in climate. As many authors have stated that fact, provides support of the assertion that there is a strong external climate forcing function. The forcing event occurs regardless of the state of the planet's climate.

How the planet's responses to the external forcing function, depends on the state of the planet's climate at the time of the occurrence of the external forcing event.

http://www.esd.ornl.gov/projects/qen/transit.html

Quote:

II.2.a. Interstadials.
Sudden and short-lived warm events occurred many times during the generally colder conditions that prevailed between 110,000 and 10,000 years ago (isotope Stages 2-5.4). First picked up as brief influxes of warm climate plants and insects into the glacial tundra zone of northern Europe, they are known as 'interstadials' to distinguish them from the cold phases or 'stadials' (Lowe & Walker 1984). The interstadials show up strongly in the Greenland ice core records. Between 115,000 and 14,000 years ago, 24 of these warm events have been recognized in the Greenland ice cores (where they are called 'Dansgaard-Oeschger events'; e.g., Bond et al., 1993; Bond and Lotti, 1995). Many lesser warming events have also been seen in the ice core records (e.g., Dansgaard et al., 1993; Taylor et al., 1993; 1997; Mayewski et al., 1997) but have not yet been recognized elsewhere. Short-lived and/or moist warm phases, coeval with interstadials, appear in the eastern Pacific (Behl and Kennett 1996), western Siberia, the Arabian Sea (Schulz et al., 1998) …

Quote:

…Ocean Drilling Program Leg 169S, Saanich Inlet, British Coumbia, Canada). Ice core and ocean data suggest that interstadials both began and ended suddenly, though in general the 'jump' in climate at the start of an interstadial was followed by a more gradual decline involving a stepwise series of smaller cooling events and often a fairly large terminal cooling event which returned conditions to the colder 'glacial' state (e.g., Rasmussen et al., 1997). From the ice core evidence from Greenland, warming into each interstadial occurred over a few decades or less, and the overall duration of some of these warm phases may have been just a few decades, while others vary in length from a few centuries to nearly two thousand years (e.g, Mayewski et al., 1997).