November 25, 2017, by Tim Radford
Mark of the Anthropocene? A UK tyre dump. Image: By Cugerbrant, via Wikimedia Commons
The Earth has entered a new planetary epoch. And another 25 million kilometres of road in a few decades will mean a human-dominated planet.
LONDON, 25 November, 2017 – Never mind the formalities: a new planetary epoch, the Anthropocene, has already begun.
One of the indicators is the global road programme. The latest evidence that humans have precipitated a new geological era could be that two-thousand-year-old marvel, the road.
Within the next 30 years, according to two scientists, there could be another 25 million kilometres of road worldwide – enough to encircle the planet 600 times.
And nine tenths of all the new infrastructure will be in the world’s developing nations, chiefly in the tropics and subtropics that are home to the greatest areas of biological diversity.
William Laurance of James Cook University in Cairns, Australia, and Irene Burgués Arrea from the Alliance of Leading Environmental Researchers and Thinkers (ALERT) in Costa Rica say these new roads could open “a Pandora’s Box of environmental ills, such as land encroachment, wildlife poaching, forest fragmentation, exotic species invasions and illegal mining.”
The new roads are likely to be built because, by 2030, there could be two billion vehicles on the planet.
From 1993 to 2009, the two scientists argue in the journal Science, the extent of global wilderness declined by about one tenth. Now, around 70% of the world’s forests occur within one kilometre of a forest edge, and once vital habitats are at risk.
In the Brazilian Amazon, 95% of all illegal deforestation now happens within 5.5 km of an illegal or legal road.
And, the scientists argue, the roads may not even be of value to the communities that build them. Few are adequately engineered, because road constructors cut corners on materials and cement while siphoning off construction funds.
They quote a World Bank study: 15 to 30% (and in some cases 60%) of road funding in developing nations is lost to cartels and corruption.
“The mid-20th century represents the most sensible level for the beginning of the Anthropocene – as it brought in large global changes to many of the Earth’s fundamental chemical cycles”
But the world may be on the road to enduring environmental change anyway, according to a new study in the journal Anthropocene.
A research team known as the Anthropocene Working Group now believes that humans have already changed the course of Earth history.
Geologists have dubbed the present epoch – the warm spell after the Ice Ages – the Holocene. For most of the Holocene it was possible to regard humankind as just another species.
But, since 2009, geologists and biologists have been arguing that the human alteration of the planetary economy and its natural functioning has been so profound that it might be time to change the label.
“Our findings suggest that the Anthropocene should follow on from the Holocene Epoch that has seen 11.7 thousand years of relative environmental stability, since the retreat of the last Ice Age, as we enter a more unstable and rapidly evolving phase of our planet’s history,” said Jan Zalasiewicz of the school of geography, geology and the environment at the University of Leicester, UK, who led the study.
And his palaeobiologist colleague Mark Williams said: “Geologically, the mid-20th century represents the most sensible level for the beginning of the Anthropocene – as it brought in large global changes to many of the Earth’s fundamental chemical cycles, such as those of carbon, nitrogen and phosphorus, and also very large amounts of novel materials such as plastics, concrete and aluminium, which will help build the strata of the future.”
That doesn’t mean that the new name will stick: the final decision will be taken by the highest level of palaeontological bureaucracy, a body called the sub-commission on quaternary stratigraphy of the International Commission on Stratigraphy. But the Leicester scientists feel they have made the case.
Professor Colin Waters of the British Geological Survey said “There is no guarantee of the success of this process – the Geological Time Scale is meant to be stable, and is not easily changed. Whatever decision is ultimately made, the geological reality of the Anthropocene is now clear.” – Climate News Network
Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.