About half a billion years ago some very simple life forms developed on our planet, and the time since then has been divided up into very long geological periods that are named after the remains found in rocks and other deposits.

These early life forms were bacteria and simple wood lice-type creatures, trilobites, that became fossils in Wales, and so the succession starts with the Cambrian, the classical name for Wales. More recently, 350 million years ago, the abundant trees led to the formation of coal, hence the name Carboniferous. The Pleistocene, the Ice Age that ended just 12,000 years ago, takes its name from the Greek for ‘mostly recent’.

Since then, the present, the time when human civilisations developed, has been called the Holocene – the Greek for ‘entirely recent’. However there’s a case to be made for a new geological period, the Anthropocene, which is thought to have begun around 1760, with industrialisation, though it could have started with the first settled farming. It marks the first time that a life form has significantly changed the planet, and takes its name from the study of humankind – anthropology.

It’s not yet formally recognised as a new geological period, but it does seem to pass the test of leaving a mark that those in the future will be able to identify.

It’s worrying that while our species has made very little progress in sorting out inequality, or finding an alternative to warfare, we have been spectacularly successful with our scientific and technological progress. Even using current skills, future scientists will have a field day with the fingerprints of our lifestyles.

They are now able to tease out the climate and vegetation of past periods over many hundreds of thousands of years, using a wide range of analytical techniques from tree rings, sediments in lakes and oceans, pollen analysis, coral growth, hydrogen and oxygen isotope differences in shells, and air trapped in bubbles in ice sheets.

From Antarctic ice cores they have deduced the climate for the last 800,000 years, and during that time the CO2 level in the atmosphere was never higher than 280 parts per million. That is, until now. In the last 60 years the figure has shot up, reaching 400 ppm in 2013, an unprecedented increase of 30 per cent in less than a human lifetime, and it’s still rising at more than two ppm every year. Awareness of our growing impact led to the first climate conference, in Rio in 1992, just 22 years ago, and since then the CO2 in the atmosphere has increased by 50 ppm.

We seem determined to make our mark.