With the earlier estimate, scientists had thought that the balbarids went extinct because of a drastic change in Earth's climate, which would line up with the extinctions of many land and marine animals in the middle of the Miocene (http://www.ucmp.berkeley.edu/tertiary/miocene.php) as climate conditions shifted , a warming period known as the Miocene Climatic Optimum
. But if they did indeed survive for several million more years, it could have been competition with other prehistoric kangaroos that did them in - specifically, the ones without the huge canines.
We arerising from the Maunder Minimumcold period, which followed the Lesser Climatic Optimum
, when temperatures were higher than now, in about 1,000 AD.
Eocene Thermal Maximum 2 (ETM2; ~53.7Ma) or Early Eocene Climatic Optimum
The Miocene Climatic Optimum
(MCO), recorded ~17 to 15 Ma, represents one of the warmest periods of the last 30 million years (Zachos et al., 2001; Shevenell et al.
Dinoflagellates, cercozoa, eustigmatophytes, and haptophyte algae responded most dramatically to the gradual increase in salinity after the latest marine reconnection and during the warm and moist mid-Holocene climatic optimum
The Holocene marine layer's maximum extension represents the paleoshoreline during the Holocene climatic optimum
(4000BC), when the sea level was at its highest.
Temperatures would have to rise considerably before they exceeded those in the "climatic optimum
" 5,000 years ago and there is no good reason to believe that they will.
Like other Siberian researchers, Khlobystin recognizes that any humans in far northern Siberia removed southward during the cold period (roughly correlated with the Younger Dryas) that followed the interstadial, leaving the region unpopulated until warmed by the climatic optimum
. Thus the earliest clearly attested and lasting occupations in the far North appeared in the period he classes as Mesolithic (a concept he discusses at length, given the variation in usage among Russian authors).
Some authors suggest dry mid-Holocene conditions (Prieto 1996), while others interpret the record as evidencing a moister mid-Holocene climate (from 8500 RCYBP to 3500 RCYBP), based on the concept of "Climatic Optimum
" or Hypsithermal (Iriondo 1999; Krohling 1999; Krohling and Iriondo 1999).
"Positive Feedbacks" contains those changes deemed the "biological" origins of modernity in other words, the effects of the "Little Climatic Optimum
" on climate, land use, agricultural practice and their concurrent effect on population growth.
They did not exist during the "climatic optimum
", which ended in the Bronze Age.