Our impact is so enormous, geologists have named an epoch after us

Opinion: In Earth time and terms, we humans pack the punch of a massive nuclear explosion or a big asteroid hit.

In the past 70 years – a split second in Earth’s 4.5-billion-year life to date – our eight-fold increase in our greenhouse gas emissions has triggered lightning-fast changes in the planet’s climate and the rest of nature, our life support system.

Sure, we took the past couple of centuries to grow the population and build the energy, economic and technology systems that have triggered that eruption of emissions since 1950. Yet, even those few hundred years were but a blip in Earth time.

But we have done enough, fast enough, to cause profound changes in the five, inter-linked Earth systems: the atmosphere, hydrosphere, biosphere, cryosphere and geosphere.

Moreover, the speed of change of all five systems is accelerating, and the changes are feeding on each other in a reinforcing cycle.

Quite simply, nature is now changing far faster than we humans are – and that’s on a human time scale, not a planetary one.

Across all five Earth systems, nature is moving far faster than we modelled or are responding to. Examples are forest fires, biodiversity loss, ice loss, and, above all, ocean heating.

“Scientists are freaking out about ocean temperatures – it’s like an omen of the future,” the New York Times wrote this week.

Of course, we humans are a mere blip in Earth time. Climate change (triggered by nature, not by a species) about 75,000 years ago caused the entire human population of the planet to shrink to some 15,000 fertile adults worldwide, most of them confined to a high plateau that today we call northern Ethiopia.

“We’ve never been so close – in fact, one cannot be closer – to extinction,” wrote Johan Rockström and Mattias Klum in their 2015 book, Big World Small Planet. Rockström, a Swedish scientist, was one of the pioneers of the Earth Systems science discipline some 40 years ago.

One of the influential fruits of that science field is the Planetary Boundaries framework produced by the Stockholm Resilience Centre under Rockström’s leadership. These are the nine boundaries, physical and geochemical, within which humanity must live if we want a long future on this planet. But over the past couple of decades we’ve broken through all nine.

We still try to fool ourselves that our planetary impact is so small, or that the Earth will somehow adjust and recover in ways that will still suit us. So, we keep accelerating the rate at which we emit greenhouse gases, extract natural resources, degrade the biosphere, kill off species, and generally trash the planet, which is simply our life support system.

Science shows us how delusional we are. As does common sense. We can see, hear, feel, taste and smell the damage we’re doing.

Our impact is so enormous, we humans are now the biggest single driver of planetary change.

Thus, geologist have named a new geological epoch after us. We are now in the Anthropocene.

To identify each epoch and era in the geological history of the world, scientists find a unique marker detectable everywhere on the planet. For the Anthropocene, they chose a human-made radioactive isotope created in airborne nuclear explosions – the two bombs dropped on the Japanese and the 528 airborne nuclear tests to date.

The geologists set 1950 as the start of our epoch, just as airborne tests were proliferating. That was also the date when human activity began to rapidly ramp up after World War Two, as did our impact on the Earth.

Termed the Great Acceleration, this phenomenon of human progress and destruction is summarised in nine socio-economic measures since 1750 (the start of the Industrial Revolution), and nine markers of Earth Systems’ health.

While nature is racing away with profound systems change, we humans are tinkering with incremental change. That’s doubly dangerous.

We keep fuelling nature’s system changes which are increasingly intolerable for us; and we keep avoiding the radical human solutions that would ensure everything we do works with nature, not against it. In other words, actions that would give us a liveable future.

Of course, it’s hard to let go of the systems and technologies that have got us this far. In every field of human endeavour, we seek short-term gains. If we’re winners, we hang on to what we’ve got. If we’re losers, it’s hard to notch up wins of our own. Even harder to reform the systems.

So, true sustainability, in all senses of that word – economic, social, ecological, and cultural – eludes us.

Doing what we’re doing just a bit better or a tad faster dooms us to failure. For example, here in New Zealand we’ve been picking away at a bit more renewable electricity, a few electric cars, tentative steps in decarbonising industry and making farming slightly more sustainable.

Meanwhile, we’re faltering on housing affordability, inequality of income, wealth and opportunities, education, health, environmental measures, and other benchmarks of a thriving society.

We, along with the rest of humankind, must figure out how to achieve an utterly unprecedent speed of change, scale of change and complexity of change. Everything, everywhere, all at once – to borrow from the multiverse film that scooped last year’s Oscars. 

The first step is to own up to the crises we’re creating; the second is to admit the failure of our current ways of trying to fix them; and the third is to find ways to discuss, conceive, commit to and achieve rapid and deep systemic change that will give us a future.

But we can only do that if we transcend our short-termism and our social and political divides. That’s the new focus of this column, which henceforth will be longer and monthly as I embark on a big overhaul of my knowledge.

In my search for solutions, many people past and present will inspire me. Starting with those 15,000 or so human survivors trapped by extreme climate shifts in Africa 75,000 years ago. Their only solution was to move on in the hope that Nature would provide food and more benign conditions elsewhere.

It did. But it was some 50,000 years before, as Rockström and Klum write, “the Earth’s stormy climate tapered off, as we left the last ice age and entered a planetary state of natural harmony” in which humanity has flourished.

Then about 12,000 years ago, the climate became so benign and settled humans learnt how to be farmers rather than hunter-gatherers. More settled and secure, they figured out how to develop new social structures and technologies. Thus began our extraordinary ascent in knowledge and power.

Geologists named that epoch the Holocene. But that’s now over and Nature is changing dramatically once more. This time because of us.

We’ve caused the Anthropocene. It’s entirely on us whether we figure out how to survive it. If we don’t the Earth will carry on, vastly changed, without us.