by piersmajestyk » Sun Mar 02, 2008 8:23 pm
past weather patterns/temperatures can be ascertained pretty damn accurately looking at the pollen record of plants from sediment cores. many plants have a very limited temperature in which they can live and thrive. as temperature drops or rises one way to escape the unfavorable changes is to migrate up or down the elevational gradient. ex. temperature is slowly rising then the population of the species move down the slope which is warmer and vice versa for colder climatic changes. if we now know that species A, B, and C only exist between 600-1000 meters in elevation but we find their pollen record in the sediment cores at say 2500 meters elevation over some past history and then using that information along with our knowledge of changes of temperature as one climbs elevation we can get a pretty good picture of very long term temperature changes (50k years or more depending on the area you are looking at). If temperatures are changing through normal, cyclical patterns then plants can adapt to these changes by slowly migrating, what we are looking at now though are temperatures that are increasing at rates that the plants don't have time to adapt to through movement up or down the slope. when this happens this is going to have catastrophic consequences for many, many species of plants that are not adaptable to wide ranging climatic changes and along with them all of the other organisms associated with them. the earth has gone through many, many cyclical patterns of warming and cooling. the difference between those patterns and what we are seeing now is the rapid nature of that change over a very short period of time (geologically speaking) which will ultimately be the death knell of millions upon millions of species that don't have the time to acclimate to the changes. I can assure you that doesn't bode very well for us.