What Manhattan may have looked like...

Often, as I've travelled and lived in different parts of the globe, I've stood on mountains and beaches and looked around, somewhat wistfully, trying to visualise how those landscapes would have looked a few centuries ago. I'm sure you've done it too.

Many, if not most, of these places were once vast tracts of old growth forest, with rich diversity in flora and fauna. Natural biological water cleaning systems were in place, as the hydrological cycle was efficient and largely unmolested by man. Most places still had rich, dark soils and no chemicals had yet been employed to stamp out soil life.

These were the days of 280ppm. We lived then with respect, if not even fear, for a nature wide and wonderful - never for a moment thinking we could one day be the cause of these vast and mysterious systems collapsing wholesale.

But, that was then. The industrial revolution, in combination with the exponential function that has taken the human population into a steep hockey stick incline (it took from the dawn of time until the 1800s before we reached our first billion people, but we've multiplied that almost seven times in the two centuries since), has landed us in a world that looks vastly different today.

Ascension Island, in the South Atlantic (source)

It seems Darwin was a permaculturist!

In his days globetrotting aboard HMS Beagle, Darwin set in motion the transformation of a dead, volcanic island rock - Ascension Island, described by nearby islanders as "a cinder" - into a green, rain-creating oasis. How did he do it?

Ascension was an arid island, buffeted by dry trade winds from southern Africa. Devoid of trees at the time of Darwin and Hooker's visits, the little rain that did fall quickly evaporated away.

Egged on by Darwin, in 1847 Hooker advised the Royal Navy to set in motion an elaborate plan. With the help of Kew Gardens - where Hooker's father was director - shipments of trees were to be sent to Ascension.

The idea was breathtakingly simple. Trees would capture more rain, reduce evaporation and create rich, loamy soils. The "cinder" would become a garden.

So, beginning in 1850 and continuing year after year, ships started to come. Each deposited a motley assortment of plants from botanical gardens in Europe, South Africa and Argentina.

Soon, on the highest peak at 859m (2,817ft), great changes were afoot. By the late 1870s, eucalyptus, Norfolk Island pine, bamboo, and banana had all run riot. - BBC

And he did it by breaking what is to some a cardinal rule, the rule of not using non-native plant species. (This island never had any 'natives', as it came into existence from being vomited up out of the ocean through volcanic activity.)