It is ‘hard to find analogues’ where the rate of change has been as fast as it is today, say climate experts. Viewed through a long enough lens, our climate can seem unremarkable – but for humans it is unprecedented
Those who piece together what past climates were like – a practice known as palaeoclimatology – find that today’s temperatures are, when narrowly viewed, unremarkable.
For example, the Eocene, an epoch lasting from 56 million years to 34 million years ago, was “screamingly hotter” than today, by about 10-15C, according to Matthew Huber, an expert in historical climates at Purdue University in the US.
However, the current global temperature—about 1°C above preindustrial levels—is unparalleled in human history, since mankind has been burning mass quantities of fossil fuels. It’s the hottest it has been in at least 125,000 years, potentially even 1 million years.
“Humans have not faced a climate like this over our long history; we are starting to hit temperatures that are unprecedented,” said Huber. “It’s not like we will all become extinct, but we are messing with a thermostat that is pushing [us] outside a window we have been in during all of human civilisation.”
Our planet’s climate has been relatively stable for the past 10,000 years, creating conditions that allowed human civilization to flourish. But now, as global temperatures rise, we are being wrenched from this stable era into uncharted territory.
If global temperatures rise by 3°C this century—without rapid action to curb emissions—conditions could resemble the Miocene epoch, 23 million years ago, when sea levels were tens of meters higher, and the polar ice was minimal. Such a scenario would devastate modern infrastructure, most of which was never designed to withstand extreme climate conditions.
The most striking aspect isn’t just the heat itself but how quickly it’s changing. Earth’s temperature has risen over 1°C in just over a century—a blink of an eye in geological terms. In the past, such changes unfolded over thousands of years, giving ecosystems time to adapt. Today, the rapid pace of change is unprecedented.
“A hundred years or so is less than a blink of an eye in Earth’s history,” said Lina Pérez-Angel, a palaeoclimatologist at Brown University. “There’s nothing in Earth’s history that shows a change happening this quickly, it’s just so, so fast. Usually these changes take a long time, things can adapt. Right now the pace of change is one of the biggest concerns we have.”
This acceleration is driven by human activities, particularly the burning of fossil fuels and deforestation, which have radically increased atmospheric carbon dioxide levels. We’re essentially reversing natural processes, digging up ancient carbon, and creating a self-imposed climate crisis.
The last time carbon dioxide levels were this high, causing the atmosphere and oceans to heat up, was about 3m years ago. Prior to about 800,000 years ago the atmospheric concentration of CO2 was never more than 300 parts per million – that rate has now sailed well beyond 400ppm.
Experts are clear: we have the power to stop this. The question is, will we act in time?
Source: Journalist Oliver Milman and graphics by Tural Ahmedzade
