Human Environmental Engineering Goes Back a Long, Long Time

An alien species visiting Earth would find a planet clearly dominated by one species. It’s no secret that humanity has a major influence on all aspects of Earth processes – we’ve covered major portions of land surface in stone and asphalt; we’ve cleared natural landscapes and driven an ever-increasing number of species to extinction; we’ve filled the oceans with plastic and the atmosphere with greenhouse gases. This planet is very firmly in the grip of human activity.

But this legacy of environmental modification goes back further than we generally appreciate. Today’s issue of PNAS has a special section devoted to human evolution, and one paper outlines the modern understanding of the many ways our species has affected the physical world around us, and just how long we’ve been doing it. The fact is that our modern explorers – the intrepid adventurers of the past few centuries who discovered lands populated only by indigenous peoples or long-gone civilizations – were alien visitors to parts of the planet already dramatically transformed by human influence.

Here are some of the ways our species has been shaping natural environments since long before written history:

Ghost World - Part III: Resurrection

De-extinction. It's an amazing and controversial idea, and it may even be impossible. It's also not what you think. 

In Part I of this series, I reviewed the ways in which our world is a poor impersonation of what it was thousands of years ago, haunted by the absence of the ancient giants that once provided stability to ecosystems. In Part II, I reviewed the ways in which modern researchers are hoping to fix those ecosystems, by transporting "replacement" species to fill the gaps left by extinction, and even "un-domesticate" certain species to recreate their wild ancestors. 

Isn't there another option though? Instead of trying to replace the dead, why not bring them back? Why not simply clone extinct species?

Ghost World - Part II: Revival

In my last post, I described how the modern-day world is a global version of a ghost town: the extinction of dozens of species of large animals at the end of the Pleistocene Epoch left ecosystems incomplete and unbalanced. Without mammoths, ground sloths, and the rest, some plants and animals have thrived, others have suffered or disappeared altogether, and even natural processes like fire and climate have been affected. The natural world is incomplete without them, and continues to degrade like an abandoned village.

Of course, the key to “fixing” a ghost town is quite simple: bring people back. They don’t even have to be the same people. Just about anyone can tend the overgrown gardens, drive the disused cars, and shoo away the rats and roaches. The same may be true of our ecosystems, which brings me to an ambitious – and controversial – conservation idea:

Pleistocene Rewilding.

Ghost World - Part I. Dearly Departed

Imagine walking into a ghost town, recently deserted. It wouldn’t take you long to realize what’s missing. Cars are still parked along the streets, batteries slowly failing; sprinkler systems still spring to life on schedule, watering lawns that are steadily growing out of control; untended gardens are gradually overtaken by weeds, while insects and rodents dart in and out of homes with nothing to stop them but cats turned feral now that no one is leaving food out for them. All of these things are meant to be there, but they aren’t doing what they’re meant to do. Without people to maintain the town, it has descended into disrepair and instability.

Our world is in a state of disrepair and instability for the same reason – something important is missing. We live in a ghost world.

Watch the World Change

A slightly belated Happy Earth Day to everyone!

One of my jobs at the museum this month was to set up a bunch of interactive tables for our Earth Day celebration.  My favorite of the tables was labeled “The Changing Environment” and it featured a series of maps, on paper and on slide shows, showing how our planet has changed in recent years, largely due to human activities.  Maps are a great visual representation of the state of the planet, and some of the maps I found were quite powerful.  I thought I'd share them.

Flashback

With each new blog post, I try to find some big important new research to talk about, and I try to vary the topics as much as I can.  But just because I posted about something already doesn’t mean that research has stopped, and every now and then I find some new developments in news I've already blogged about.  Here are some recent updates to previous topics I've mentioned:

Turning Over a Fake Leaf in Energy Research

They’re calling it an “artificial leaf,” although that’s not technically accurate.  It’s small and thin, and like a leaf, it uses water along with energy from the sun to produce fuel, but aside from that, it’s really not much like a leaf at all.  What it is is a new, advanced form of solar panel capable of cheaply producing lots of energy, and it might just be the future of solar energy. 

How does it work?  A real leaf (pictured left) performs photosynthesis – pulling together water and carbon dioxide and using the energy from the sun to turn those ingredients into fuel for the plant.  This “artificial leaf,” brainchild of a collection of researchers at MIT, harnesses the power of sunlight and uses it to cut water in half!  Actually, into three pieces – with the help of special catalysts, this leaf splits H₂O into two H’s and an O.  The free H (hydrogen) can then be used as a fuel source.