Archive by category | Palaeoclimate

The real holes in climate science

When I started working last month on a news feature about gaps in climate science I was expecting a tough reporting job. Too fresh, so I thought, were the scars the field and many leading scientists had received from the hacking affair at the Climate Research Unit (CRU) in Norwich to readily discuss with a reporter the ‘dirty laundry’ (my phrase) of climate science.  Read more

Climate change warning from Greenland

The Greenland ice sheet melted much more rapidly as a result of warmer temperatures in the recent past than previously estimated, a team of international scientists has revealed. They warn that future warming could have more dramatic effects on the ice than researchers have assumed. The research is from this week’s Nature and there’s a news story about it over at Nature News.  Read more

Timeline: Ice memory

Some of scientists’ gravest concerns about future climate change are rooted in the past. Records studied by paleoclimatologists reveal that the more extreme possibilities for this century and beyond — temperatures soaring, ice sheets vanishing, fertile lands withering into deserts — were realized previously on Earth when atmospheric greenhouse gas levels surged. At this summer’s AGU Chapman Conference on Abrupt Climate Change, researchers described this turbulent history through all manner of proxies – ice, tree rings, corals, marine and lake sediments, among others. But few talks went without a slide showing the wiggly line of a deep ice core.  Read more

Indian Ocean: Gatekeeper to climate extremes?

Indian Ocean: Gatekeeper to climate extremes?

Some glacial periods in the Earth’s more recent geological past have been cooler and more severe than others, despite very similar greenhouse gas concentrations and orbital parameters. What is it that decouples global temperature from carbon dioxide levels and the solar heat?  Read more

Unknown climate culprit for Palaeocene-Eocene warming

Unknown climate culprit for Palaeocene-Eocene warming

A reconstruction of the Earth’s climatic history during a key hot period 55 million years ago has highlighted a yawning gap in our understanding: this period’s rise in carbon dioxide accounts for just half of its warming. Some as-yet-unidentified climate feedbacks could be at work, the scientists behind the research conclude.  Read more

Interview: Lonnie Thompson

Interview: Lonnie Thompson

At the AGU Chapman Conference last month I met up with Lonnie Thompson, the alpine glaciologist who has spent more time above 20,000 feet than any other human. Despite being interrupted by last-minute demands from Peruvian customs officials – he was squeezing me in before taking off for a new expedition in the Andes – an unphased Thompson carefully laid out the past and present-day climate change that his work has uncovered. Here’s an extract: What information can you garner from glaciers? Glaciers are like sentinels, and they’re telling us that the system is changing. The first thing we look  … Read more

The greening of the pre-Cambrian

The greening of the pre-Cambrian

It’s one of the biggest problems in the Earth’s history: What prompted the Cambrian explosion of multi-cellular animal life? (Though calling it the ‘Cambrian explosion’ is a misnomer at this point; most geologists agree that life took off a bit earlier than the Cambrian 540 million years ago — probably 50 million years or so before that boundary.)  … Read more

Plant power

Why carbon dioxide concentrations over the past 24 million years or so have never dropped below 200 parts per million, despite environmental conditions that have been favourable for CO2 drawdown by rock weathering and sedimentation, has always been a bit of a mystery.  Read more

AGU Chapman Conference: Megadrought in Dixieland

AGU Chapman Conference: Megadrought in Dixieland

A never-before-seen megadrought made an appearance this morning at the last day of the AGU Chapman Conference. Paul Aharon of the University of Alabama says his latest observations are the first to suggest that drought affected the southeastern United States from about 13,000 to 11,800 years ago – during the so-called Younger Dryas cool period.  Read more