It’s not climate change – it’s climate reversal

The climate has always changed, but never reversed at this rate; What took millions of years has been released in the last 150 years, writes David Higginbottom.

THIS ARTICLE resulted from a discussion with a neighbor who told me with absolute authority: “Climate change has always existed”. While technically true, it’s also one of the most misleading things climate change skeptics say.

The “climate has always changed” argument is used as a tranquilizer: Everything was different before; They will be different again, nature will adapt, continue life, enjoy it.

But this framing completely misunderstands the changes that have occurred before.

Yes, Earth’s climate has changed throughout its history. It was much hotter and colder than today. Glaciers swallowed continents. Deep seas covered what are now mountain ranges. Climate change has always existed.

But what this argument almost always misses is that even though the Earth has experienced thermal shocks in its past:

For tens of millions of years, the general trend had been moving in a certain direction. We have reversed this in just 150 years.

What did we do? -The took a big breath

Beginning approximately 500 million years ago and accelerating over time carboniferous During the period (about 360 to 300 million years ago), vast forests of ancient trees collapsed into swamps and were buried beneath layers of sediment before they could fully decompose. Trillions of marine microorganisms died and sank to the seafloor. At each funeral, carbon floating in the atmosphere as CO2 was captured and locked underground.

And this process was incredibly slow. It happened over periods of time that made human civilization look like a rounding error. Over millions of years, atmospheric CO2 has fallen. The planet has cooled. Stable, temperate climates became possible. The conditions that made complex animal life (and ultimately us) habitable were the result of this removal of carbon from the planet.

By the time our species emerged, and certainly by the time we built our first cities, the atmosphere had settled into a stable, rhythmic cycle. Pre-industrial CO2 fluctuated within a safe range and was around 280 parts per million in warm times; It was low by the standards of deep geological history and ideal for human flourishing.

Climate stability was the legacy of hundreds of millions of years of CO2 sinking.

Ages return in 150 years

Starting with Industrial revolution We began digging and burning these ancient, buried forests in the early 19th century. We dug up the compressed remains of sea creatures and burned them too. By doing this, we began to release carbon that had been underground since before the dinosaurs; This is the carbon that nature has spent unimaginable periods of time removing from the air.

By 2025, atmospheric CO2 had reached approximately 425 parts per million; this was a 50 percent increase over pre-industrial levels reached in 150 years.

Hundreds of millions of years of isolation. A one hundred and fifty year return.

University of Chicago climate scientist David Archer, in his indispensable book Long Thaw (2009) puts it exactly like this:

‘It took millions of years for the carbon we emitted to accumulate underground’ — Once released, a significant portion will remain in the atmosphere for hundreds of thousands of years.’

It’s the ratio that matters

Here the “climate has always changed” argument completely collapses.

Natural climate change occurs. It’s happening slowly. Scientists drilling through Antarctic ice can read 800,000 years of atmospheric history in these cores; old air bubbles trapped layer by layer as snow trapped in the ice. British Antarctic Survey to have carefully analyzed these records. The fastest natural increase in CO2 they have ever measured is about 15 parts per million over about 200 years.

We are actually increasing CO2 by 15 parts per million every six years. This is not a faster version of natural climate change. This is a categorically different event; In geological terms, it’s closer to a mass extinction trigger than a natural cycle.

Czech-Canadian academic Vaclav Smil (2017) He also touches upon an important point about fossil fuels:

‘These are ancient reservoirs of solar energy accumulated by biological processes over geological ages and compressed by time and pressure. When we burn them, we don’t just use energy; We are also removing a geological legacy that took years to build.’

Direction is important

Climate change advocates and skeptics have a long history of arguing over the extent of change and how quickly it is happening. But the real point is about the vector: Which way did the planet go, and which way are we pushing it now?

The general trend over tens of millions of years was towards lower CO2, cooler temperatures and greater climate stability. Particularly over the last 35 million years, Earth has been on a slow trajectory towards conditions that would eventually allow humanity to thrive.

We didn’t just accelerate climate change. We reversed direction with a speed that has no geological equivalent.

IPCC’s Sixth Assessment Report (2021) The most comprehensive scientific synthesis on the subject ever produced confirms that there is no precedent in the 800,000-year-old ice core record for what is currently happening to atmospheric CO2. Not in proportion, not in size for this age.

What does this mean?

Understanding the geological scale of what we are doing is not a recommendation of despair, but underscores urgency. while we were playing war gamesOur planet is approaching a tipping point, and don’t believe that your country, position, or privilege will make you immune.

We inherited a planet that spent hundreds of millions of years cooling itself, sequestering its carbon and creating stable conditions for complex life. In a geological moment, exactly a century and a half, we began to undo this work.

The climate has always changed. But it has never gone backwards at this rate, destroying millions of years of planetary history in a few decades. We didn’t just change the climate; we are reversing this and compressing this change into the human lifespan. What took millions of years to be held in place has been released in the last 150 years.

The climate system will eventually find a new balance. The question is whether the civilizations and ecosystems on which we depend can survive this transition.

David Higginbottom is a member of the coordinating committee. Independent and Peaceful Australia Network (IPAN) and coordinator of the Make Peace Our Priority campaign (mpap.au).

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