The year is 9,700 BC. The Ice AgeA long period of time in which global temperatures are extremely cold. is over and a new age dawns, known as the HoloceneA period of geological time starting 11,700 years ago - at the end of the last Ice Age. . Humans are starting to domesticateTame an animal and keep it as a pet or farm animal. other animals.

The year is 1952. The USA detonates the world's first hydrogen bombAn extremely destructive bomb. The energy comes from hydrogen atoms fusing to form helium. over the Pacific Ocean, scattering radiation over the planet.

In geological terms, the time between these dates is a blink of an eye. But it marks one of the most momentous changes in Earth's history: human beings started having an impact on the climate.

That is why last week, scientists announced that this is proof that the Holocene is over and a new epochA particular time period. has begun. They call it the AnthropoceneThe term was coined in the 1980s, but became more common in the last decade, popularised by the Dutch climate scientist Paul J Crutzen. It is new name alluding to the current geological epoch, echoing the names given to earlier epochs, such as Pleistocene, and the Anthropocene's predecessor, the Holocene. The word comes from the Greek "anthropos", meaning Man, and "-cene", meaning new. Most geologists, however, would say we are still in the Holocene..

They made this claim against a backdrop of punishing summer temperatures, driven, scientists believe, by climate breakdown.

That is why some think the Anthropocene is a wake-up call. They say we need to stop using fossil fuels now.

Scientists estimate that every 0.1 degree of warming pushes 140 million people out of climates that human beings are adapted to live in.¹

So anything other than an immediate ban on fossil fuelsFuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming., they say, would be immoral. We are killing people every moment we keep burning them.

Moreover, there is little sign that we are on track to meet even our current deadly target. Scientists are now 98% certain that we will breach the 1.5C limit before 2027.²

Others think a total ban could be far more harmful to the world's poorest people. It would strand billions of people in poverty. This hardly seems fair, they claim, when developed countries have already got rich from them.

But some say net zeroWhen the gases going into the atmosphere are balanced by those being taken out of it. is an opportunity for the developing world. Many of the world's poorest countries have abundant renewableEnergy sources, such as wind and solar power. energy resources. Given the funds to unlock them, they could kick off a new era of clean global development - and finally rebury fossil fuels.

Yes: Every slight increase in the planet's temperature means catastrophe for millions of people around the world. We have no choice but to keep oil and gas in the ground.

No: Like it or not, we have built a global economy around easy access to energy from fossil fuels. We cannot turn all of that on its head in a single moment. We need to transition gradually away from them.

Or... We could already be generating most of the world's energy from renewable sources, and it would be cheaper than fossil fuels. If we invest in renewables we can make fossil fuels obsoleteOutdated and no longer useful. without having to ban them.

Ice age - A long period of time in which global temperatures are extremely cold.

Holocene - A period of geological time starting 11,700 years ago - at the end of the last Ice Age.

Domesticate - Tame an animal and keep it as a pet or farm animal.

Hydrogen bomb - An extremely destructive bomb. The energy comes from hydrogen atoms fusing to form helium.

Epoch - A particular time period.

Anthropocene - The term was coined in the 1980s, but became more common in the last decade, popularised by the Dutch climate scientist Paul J Crutzen. It is new name alluding to the current geological epoch, echoing the names given to earlier epochs, such as Pleistocene, and the Anthropocene's predecessor, the Holocene. The word comes from the Greek "anthropos", meaning Man, and "-cene", meaning new. Most geologists, however, would say we are still in the Holocene.

Fossil fuels - Fuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming.

Net zero - When the gases going into the atmosphere are balanced by those being taken out of it.

Renewable - Energy sources, such as wind and solar power.

Obsolete - Outdated and no longer useful.