Sand surrounds us–and while it may seem in infinite supply, it is not. Currently, sand is being used up much faster than it is being replenished. Sand and gravel, collectively known as aggregate, are the most widely extracted solid materials on Earth. A recent report by the United Nations Environment Programme recognizes sand as a strategic resource–and one with looming challenges.
When I first visited the Peruvian Andes, I was astonished to see groves of eucalyptus — native Australian trees — at elevations greater than 10,000 feet (3,048 m). Eucalyptus is the most widely planted non-native tree in coastal California, which has a Mediterranean-type climate like that found in parts of Australia, but why are these trees in the high Andes?
Food security is a growing concern for our global population of close to 8 billion people. The essential natural resource that controls food production is soil, which is being eroded away and degraded worldwide. Without healthy soils, our capability to provide adequate food for billions is seriously in question. Methods for improving degraded soils are available.
The demand for lithium is increasing dramatically – and sources of this metal are being sought from the high elevations of the Andes Mountains to the lowlands of Australia. Lithium is widely distributed on our planet, but since concentrations of this metal are typically quite low, relatively few ores that are economical to mine have been found to date. There are currently three major sources.
Uluru, also called Ayers Rock, the iconic giant sandstone mound in Australia that rises abruptly out of an expanse of flat desert, has always intrigued me. For thousands of years the indigenous Australians have considered Uluru a sacred site, and it is the focus of numerous myths and legends. I understand that mythic attraction – and the geologic history is just as captivating.
