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New evidence confirms manifestation of ancient mega-drought

By Nicolette Smith - 03 Mar 2011 13:48:0 GMT
New evidence confirms manifestation of ancient mega-drought

What was the weather like 10,000 years ago? If a team of international Scientists from the Los Alamos National Laboratory are to be believed, our hunter-gatherer ancestors were experiencing something of an ecological disaster during this time - a large-scale environmental 'Mega-drought' – which left animal and human lifeforms fighting for survival in an unforgiving climate amidst an agriculturally-redundant landscape.

A Mega-drought involves a period of time during which the earth's outer crust dehydrates; lakes, shrubs and plant life dry up, crops fail to grow and lifeforms both human and animal suffer accordingly. The study, published in the ecological publication Nature, revealed that a collaborative project involving researchers from the University of Mexico and the Los Alamos National Laboratory confirmed theories that the south-western region of the United States undergoes periodic conditions of drought followed by distinctly cooler, wetter, deluge-like periods.

The project, which saw the team of Scientists drilling beneath the South Mountain Lake in the Valles Caldera National Preserve in order to extract data relating to the US climate 360,000-500,000 years ago, revealed that the Earth's climate may be essentially cyclical in nature.

So what does this mean? Well, it means that the south-western regions of the US may be in for a period of cooler, wetter weather, unless this potential change is postponed by the emergence of a high concentration of greenhouse gasses. If the concentration of greenhouse gas emissions (atmospheric gasses which consume and dissipate radiation in a thermal action) increases, the 'warming' effect they produce may impede the shift in temperatures.

The findings were based upon a project involving the extraction of several examples of core sediment from beneath the dry South Mountain Lake, which were then taken away for analysis. The Valles Caldera National Preserve is the site of a dormant ancient volcano, situated on an 86,000-acre grassland not far from Los Alamos. By looking at the long layers of extracted sediment, the research team were able to look back in time to the climate changes experienced by lifeforms thousands of years ago. The multiple layers of volcanic ash made dating the layers of sediment much easier and ensured a high degree of accuracy.

By looking at trapped pollen, plant and chemical matter within the sedimentary layers, scientists were able to ascertain the nature of the climate long, long ago. The evidence indicates that the South-west underwent two interglacial periods (characterised by cold temperatures and extremely icy weather), which were both followed by milder periods more similar to the modern-day climate. The most ancient interglacial period lasted for over fifty thousand years, and included at least one instance of 'Mega-drought' weather.

Leader of the Los Alamos research group Jeffrey Heikoop said of the results: ''Results from this study have implications for the development of models that could predict future megadroughts and other climate conditions in the Southwestern United States.''

Travelling to the south-west? Take a bottle of water with you, because it looks as if the region may be in for another 50,000-year-long dry spell!