Antarctic ice cores have recorded an impressive span of climatic history for us, covering the last 800,000 years. But scientists are greedy, always looking to go back just a little further . Climate records based on things like seafloor sediment cores already take us much further back, but ice cores can reveal unique details. Groups are currently searching for locations to drill new ice cores that might provide a contiguous record back to over the million-year mark.
But another group has been cheating, and this has allowed them to take a big leap past everyone else. Instead of looking at places where the ice at the bottom might be oldest, they've been looking at places where that oldest ice has been squeezed up to the surface against high points of bedrock. A few years ago, they published data from samples of ice that came back at right about 1 million years old. At a conference on Wednesday, the researchers revealed the fruits of their second attempt—ice as old as 2.7 million years, blowing away their previous record.
The ice is fairly squished up and convoluted, with sections of ice less than 800,000 years old showing up between sections of ice between 1 million and 2.7 million years old—the effort to determine its age requires careful dating based on isotopes of argon. But the researchers are able to measure greenhouse gas concentrations from trapped air bubbles and indicators of past ocean temperature.
One reason these samples are particularly interesting is that Earth's ice age rhythm changed around 1.2 million years ago. The 800,000-year ice core record shows a sequence of ice ages that were each about 100,000 years long. Prior to 1.2 million years ago, the cycle was a little shallower and faster, with ice ages lasting only 40,000 years due to some interaction between the regular cycles in Earth's orbit and our planet's response.
- Bedbugs roamed Earth alongside dinosaurs 100 million years ago
- Meet the toddler-sized T-Rex cousin from 92 million years ago
- It Was Fifty Years Ago Today
- Mummy squirrel tells of a different Alaska 20,000 years ago
- 3.8-million-year-old fossil reveals face of Lucy's ancestors
- 3.8-million-year-old skull reveals the face of Lucy’s ancestor
- Just a concept 25 years ago, the International Appalachian Trail now crosses continents
- West Antarctic ice sheet: 25% now unstable due to global warming
- The 1977 Blackout in New York City Happened Exactly 42 Years Ago
- 12,000 years ago, a boy had his skull squashed into a cone shape
- Four Years Ago Trump Was Seen as a Sideshow. Now He Is the Show.
- Metrodome, Twins deflated in bizarre night 31 years ago
- Neolithic people made fake islands more than 5,600 years ago
- Elvis came to Las Vegas 50 years ago and history was made
- Prince died 3 years ago his estate still unsettled here's why
- 39 years ago: Mount St. Helens woke up and blew her top
- Apollo celebrates moon landing 50 years ago with town party
- A walnut tree from George Washington's estate was planted in Reading's City Park 87 years ago
- Venetian’s convention model ‘transformed’ Las Vegas Strip 20 years ago
- Seinfeld premiered 30 years ago without Elaine Benes
Oldest Antarctic ice ever found shows climate of 2.7 million years ago have 538 words, post on arstechnica.com at August 17, 2017. This is cached page on Europe Breaking News. If you want remove this page, please contact us.