28 Jan 2015
Changing our planet
For the first time in some 4.5 billion years, one species – us – is consciously changing the planet Earth.
Our nuclear fallout, carbon emissions, forest clearing, agriculture, urbanization, elimination of other species, erosion and releases of a vast array of chemicals are making the world a different place from the one that evolved naturally.
Close to half of the planet’s ice-free surface is used for agriculture and urban development. Our impacts in the atmosphere are huge. Greenhouse gases released in ever greater amounts are raising the world’s temperature and making the oceans more acidic. Our chemicals have chewed a hole in the protective ozone layer.
We humans have been making some changes to the planet for thousands of years, probably starting with the use of fire to clear landscapes for hunting. Major changes started to build with the industrial revolution, dating back to the 1700s. But the “great acceleration” of impacts began in the 1950s when human population and activities began a rapid expansion, aided by new technologies.
Geologists categorize the past into eons, eras, periods and epochs, based on how the planet has changed, based on the fossils and minerals found in layers of rocks. According to the International Union of Geological Sciences we are now in the Holocene epoch that began at the end of the last ice age, about 11,700 years ago.
Because human impacts are so great, and many will be so long lasting, scientists are looking at declaring a new geologic epoch, the Anthropocene, http://www.anthropocene.info, a period defined by human impacts on the planet.
What does this mean for sustainability? It’s simply another warning – a big one – that human impacts on our world are huge, long lasting and many are dangerous for our future. It lays out the challenge of bringing our lifestyles within planetary boundaries in a very powerful fashion.