Everything Science Forum

http://news.nationalgeographic.com/news/2005/12/1216_051216_humans_britain.html

James Owen
for National Geographic News

December 16, 2005
Stone tools found on the coast of Britain suggest early humans first colonized northern Europe much earlier than previously known.

Ancient flints discovered in cliffs at Pakefield in eastern England show humans lived in northern Europe some 700,000 years ago, according to researchers.


They say the find indicates that humans journeyed into Britain 200,000 years earlier than experts had suspected.

Flints typical of crafted tools used for butchering meat and cutting wood were found in sediments along with the remains of hippos, elephants, and other exotic animals.

The long-extinct wildlife dates the flints back to a much warmer period when Britain was still connected to continental Europe via a land bridge.

There are a number of interesting ideas in that article, including

The long-extinct wildlife dates the flints back to a much warmer period when Britain was still connected to continental Europe via a land bridge.

I suppose critics of the global warming concern would point to that and say 'see, the earth has been warmer in the past!  What's the big deal?"

Well of course, the earth is now different and the consequences of a warmer environment will be signifcantly different.  We have a lot less forested areas to buffer the weather.  Coastal communities could be more a risk for storms (e.g. Katrina and Rita).  We are heavily dependent on a reliable food supply, which could be threatened by more energetic or wet weather.  Insects like mosquitoes, which carry a variety of harmful diseases, could pose an increased threat to the human population.

Interestingly, even with the warmer weather, with presumably higher sea level (?), there was a land bridge between England and continental Europe.

Anyway, the dating issue is interesting.

The stone tools were dated using various lines of evidence, including the bones of an extinct species of prehistoric water vole called Mimomys.  Human artifacts have never before been found with the remains of this small mammal, the researchers say

Ancient snails were also used to date the Stone Age cache through a method called amino acid geochronology.  The technique measures the extent of protein breakdown in animal matter to gauge how old it is.

Amino acid geochronolgy - http://www.geo.umass.edu/amino/aalintro.html

http://jan.ucc.nau.edu/~dsk5/AAGL/

http://www.geol.vt.edu/research/gssrs/gssrs2001/abstracts/carroll.pdf

or just google on "Amino acid geochronolgy"

Interestingly, even with the warmer weather, with presumably higher sea level (?), there was a land bridge between England and continental Europe.

A warmer global temperature doesn't necessarily mean a higher sea level.  Higher temperatures also mean more evaporation, so a higher level of atmospheric water saturation.  That kind of trend, over a few thousand years, could eventually drop the sea level, instead of raising it.

Also, as you mentioned, there was more likely to be a higher level of forestation 700,000 years ago, and the forests would also act as a water-sink for precipitation.

So, there could easily have been more water in the atmosphere, and more rain as a result, but not necessarily a higher sea level.