Last week I spoke on man’s love for the earth coming and going in passing fads. After watching an interesting episode of Nova – Extreme Cave Diving, I have learned that climate change, for the most part, has been as well.
We all learned about the Ice Age in grade school, and that many dry parts of the earth were under the ocean, but none of us have experienced it. We see that the climate is changing now, and we’re blaming ourselves, but what if it isn’t entirely our fault? A team of scientists have discovered some interesting new facts while diving in these caves in the Bahamas.
Stalagmites grow from the ground up, when water passes through the rock above, and drips onto the floor, carrying with it mineral deposits. Once the cave is filled with water, the stalagmites can no longer grow; they are frozen in time, and this makes them perfect for the study of climate change.
Stalagmites give us a clue to what paleo-climate was many thousands or
Stalagmites give us a clue to what paleo-climate was many thousands or hundreds of thousands of years ago. Much of what we know about climate history comes from two sources: sediment samples from the ocean floor and cores taken from glaciers and ice sheets.
But stalagmites from a cave in the Bahamas has one major advantage in recording climate history, their location.
The Bahamas lie beside the Atlantic Gulf Stream. For millions of years, this current has carried warm, salty waters north, where they cool and sink. That drives ocean circulation, also called the Atlantic Gyre, which shapes climate.
A team of divers went down, and brought up a stalagmite to how often and how quickly climate change has happened in the past. First they have to slice it lengthwise. When you cut a stalagmite, because of how its formed, it reads much like the rings of a tree. As different minerals floated through the air and settled on the ground, they were brought through the soil with the water, building the stalagmite; embedded in each band is a sort of biography of the climate for a specific period. With analysis, scientists can describe how much it rained, what chemicals were in the rain, soil, air, and even the temperature.
Examination of the stalagmite shows evidence of more than five major climate changes over the last 80,000 years. THis corroborates findings in samples taken from ice cores. But then [the scientists] notice two curious details. First, the way the bands formed suggest that at least one of these climate episodes came on very abruptly. At the end of the last ice age, about 11,000 years ago, conditions changed radically from dry to wet within 50 years. This change was probably accompanied by a rise in temperature and sea level. And [they] notice something else: some of these climate events are preceded by a mysterious dark band. When [they] sample the dark bands, they find iron.
There is no iron in the Bahamas, the islands are made of coral. Turns out the iron came from the Sahara. When the sand gets kicked up in the Sahara, if flows with the breeze, all the way across the Atlantic Ocean, enough to cover the entire Bahamian island with red dust.
The scary part is that today, Saharan dust storms are happening with more and more frequency. This points to another bout of climate change, which Al Gore already told us about, but what he didn’t say was how quickly it could happen. Most of us are under the assumption that we will be long dead before anything major happens. It’s easy to toss a can in the trash, or leave all the lights on, if it’s only our great great grandkids will have to deal with the consequences. Thing is, we may not be that lucky. The stalagmite shows that serious climate change could happen in as little as 50 years; it has before. You might want to get your sun-screen ready!
And some business…. Last Thursday I held a competition to more aptly name Global Warming. I have a winner, even if it is by default. Architectnophilia, your term the increasingly changing, and unmeasurable deterioration of the earth’s atmosphere due to our mis-use and mismanagement of our resources, while a bit long, is the winner. I promised to start using it in all my posts to try my best to work it into the vernacular of our time. So I think I will try an acronym – ICUDEADMMoR – nice, Techno, it spells I see you dead more. That seems oddly appropriate.