Climate Change Tracker: World is at its hottest in 12,000 years

Although human beings have been around for about 200,000 years, we have never had it as good as in the past 12,000 years or so. Around then, Earth entered a new geological epoch called the Holocene, one marked by mild temperatures and a stable climate, a period in which the human race thrived, built civilisations and developed sophisticated culture. Now, because of climate change, due to anthropogenic greenhouse gas (GHG) emissions, the honeymoon of the Holocene is over.

A new, important study published on 27 January states that Earth today is hotter than it has been in the past 12,000 years. The study, Seasonal Origin Of The Thermal Maxima At The Holocene And The Last Interglacial, published in Nature, states that annual sea surface temperatures (SST) have been increasing steadily since the dawn of the Holocene. SST is a good indicator of planetary warming, because, as has been proven, the global ocean absorbs most of the atmospheric heat. In the past 50 years, the ocean has absorbed 90% of the heat generated due to global warming. The report also states that in all probability, the planet could be at its warmest in 125,000 years, though the data for this is less certain.

The scientists’ findings are based on temperature reconstructions from the geological record, using what are known as proxies: geological materials, like shells, taken, in this case, from marine sediment cores. In the course of the study, the team, from the US and China, cleared up an important point of contention about the Holocene. For the longest time, research has suggested that global temperatures had warmed up for the first 6,000 years of the Holocene; this has been seized upon to undermine climate models. The researchers of the study say there was no early heating in the Holocene, as earlier research was based on incomplete shell data reflecting only hotter, summer temperatures.

Speaking to The Guardian, the research lead, Samantha Bova of Rutgers University-New Brunswick, US, said: “We demonstrate that global average annual temperature has been rising over the last 12,000 years, contrary to previous results. This means that the modern, human-caused global warming period is accelerating a long-term increase in global temperatures, making today completely uncharted territory. It changes the baseline and emphasises just how critical it is to take our situation seriously.”