From the murky depths of an ancient lake, hidden deep within the maze of an Amazonian rain forest, a slab of mud slowly makes its way towards the surface. It is a giant punch taken from the skin of the Earth, holding twenty thousand years of history, extracted by a hollow, hundred-foot syringe. And like a freshly-caught prize fish, it is placed on the floor of an open boat for safe-keeping, glistening in the mid-day sun. The great cathedral of the Amazon forest, with buttressed columns and green stained-glass, towers round the small lake. Research scientists stand about and stare at the lifeless form, wondering if hidden deep within its innards is the key that may unlock the answer to a mystery that has haunted them for years. Somewhere in the grey ooze may be a cache of pollen grains that unravels the mystery of a prehistoric Amazon - tell-tale traces of the forest that has come and gone before, like fingerprints that give away a crime.
The Amazon past is one of the great unknowns of exploration. Researchers know how the forests of North America and Europe were built, even much about ice-age Africa and Asia. But the ice-age Amazon is, in the purest sense of the word, unexplored. In this unknown past lie the origins of the biodiversity of the richest ecosystem on earth. Long prevalent was the view of an unchanging Amazon, where the past was like the present. Species gathered in the warm and humid environment, avoiding the perils of freezing ice-age temperatures and the danger of extinction.This has been challenged by those who imagine an arid and decimated ice-age Amazon, with forests taking refuge in a few wet spots. Only after it warmed did the protected patches of plants and animals radiate back out. But new and fascinating research is uncovering evidence of cooling rather than drying, of a forest shattered by moderate cold with each passing ice age. Pollen, and mud, and the discourse of science, will show how this green cathedral was built. The theories are extremely important in today's world because we are reading the past in order to look ahead to the future. By discovering how the green cathedral was built, perhaps we can predict whether the structure can be rebuilt after the great fire which is close upon it.
The rain forest covering the vast Amazon River basin looks from the air like a uniform green carpet cut here and there by water. Actually the forest is anything but uniform. The "carpet" is the forest's canopy, formed by broad leaves of many different kinds of giant trees, and this canopy is but the topmost layer of an ecosystem supporting more species than any other region on earth. The rain forest is home to perhaps 80,000 plant species (including 600 kinds of palm alone) and possibly 30 million animal species, most of them insects.
The Amazon has often been described as an ancient ecosystem - a cradle of evolution. It has been conjectured that the stable climate of the region has allowed it to evolve slowly, producing the fantastic biodiversity present today. Current scientific work describes a much different ice-age Amazon. It was much cooler, a full thirteen degrees (F.) colder than today (enough to kill an average houseplant). Environmentalists concerned with the possible dramatic effects of global warming speak of a five degree increase in temperature. The effects of a drop in temperature almost three times that value would have overwhelming results. The immense biodiversity of the Amazon may consequently be a result of catastrophic events. Rather than a stable and static system, the Amazon may be in a continual process of rejuvenation and change. So, far from being disastrous to life in the Amazon, the moderate climatic disturbances in the region may actually help account for the splendid diversity of the Amazon rain forest today.This is one controversial new answer to the mystery of the Amazon's history.