How Antarctic ice melt can be a tipping point for the whole planet's climate Melting Antarctic ice can trigger effects on the other side of the globe. NASA/Jane PetersonChris Turney, UNSW; Jonathan Palmer, UNSW; Peter Kershaw, Monash University; Steven Phipps, University of Tasmania, and Zoë Thomas, UNSWMelting of Antarctica’s ice can trigger rapid warming on the other side of the planet, according to our new research which details how just such an abrupt climate event happened 30,000 years ago, in which the North Atlantic region warmed dramatically.This idea of “tipping points” in Earth’s system has had something of a bad rap ever since the 2004 blockbuster The Day After Tomorrow purportedly showed how melting polar ice can trigger all manner of global changes.But while the movie certainly exaggerated the speed and severity of abrupt climate change, we do know that many natural systems are vulnerable to being pushed into different modes of operation. The melting o…

The Tropics and the Furious Fifties

There’s an old sailor’s expression: “Below 40 degrees south there is no law, below 50 degrees south there is no God.” Since the sixteenth century, sailors have spoken in awe of the violent westerly winds and seas they experienced fighting their way across the Southern Ocean. With few landmasses to slow them down, the winds found across 40 degrees latitude often reach speeds of twenty-five knots—about 40 percent stronger than their northern hemisphere counterparts—earning them the title the “roaring forties.” As shipping pushed farther south, explorers realized that these winds form part of a vast storm belt that includes the “furious fifties” and “screaming sixties,” names more reminiscent of terrible rock bands than a major part of our planet’s circulation system. The early hunters and traders didn’t understand it at the time, but these winds are created by a procession of low-pressure systems carried east by the jet stream, a river of cold air hurtling and twisting round the Antarct…

Echoes of an ancient time in Australia

Exciting results published today in the international science journal Nature provide precious new insights into the arrival and movement of humans across Australia over a staggering 50,000 years. 
Sadly, many Aboriginal Australians no longer live where their ancestors had called home. So to better understand Australia’s history before the arrival of Europeans, a forward-thinking initiative called the Aboriginal Heritage Project was set up. Led by the University of Adelaide’s Australian Centre for Ancient DNA (ACAD) in partnership with the South Australian Museum and Aboriginal families and communities, the team – in which I was fortunate to play a small part – have uncovered some remarkable new findings. 
Headed by Alan Cooper and Ray Tobler, the ACAD group analysed over 100 hair samples collected with consent from Aboriginal people across the continent between the 1920s and 1970s. These samples were collected as part of a project where along with hair, detailed records of the individua…

The Day After Tomorrow

New research suggests something like the movie The Day After Tomorrow may have happened in the past, with sobering implications for the future. In this blockbuster, melting Arctic ice led to dramatic cooling across the Northern Hemisphere, highlighting the paradox that in a warming world, some regions may indeed cool (or at least not warm as much as expected). Whilst no one is suggesting this could lead to a new ice age, climate model projections do suggest some parts of the world may respond differently to long-term warming. One of the big uncertainties is the impact a melting Greenland ice sheet might have across the North Atlantic. At a simple level, the world’s oceans are connected as though by one enormous conveyor belt. At one end of the loop, warm tropical waters popularly known as the Gulf Stream drift up into the North Atlantic where over the course of a year the evaporating surface delivers heat downwind equivalent to the output from a million power stations. It’s a major re…

Ice cold in Commonwealth Bay

Commonwealth Bay in the East Antarctic will be forever associated with Sir Douglas Mawson’s pioneering scientific venture a century ago: the Australasian Antarctic Expedition. Mawson’s team had only intended to spend one year south, but it was not to be. A sudden turn of events led to tragedy on the ice, the deaths of two men, allegations of cannibalism and, with the return of winter sea ice, an extended stay in Antarctica. While the efforts of Mawson and his men laid the foundations for modern Antarctic science, the region has continued to experience dramatic change. And it doesn’t get any more dramatic than the arrival of iceberg B09B in 2011. The word ‘berg’ doesn’t really do it justice though – B09B is a monster. Weighing in at an estimated 500 billion tonnes, this block of ice is 97 miles long and over 20 kilometres wide. There’s enough freshwater in B09B to provide all of New York’s drinking needs for 300 years. And it started out even larger. In 1987, an iceberg the size of Bal…

Giving future Australian drought a 500-year perspective

Here at Intrepid Science we focus a lot of effort on trying to better reconstruct past climate and environmental change. The main reason is that by understanding what happened when in the recent geologic record we can reduce the uncertainties surrounding future climate change and its impact(s). But don’t be misled by the term ‘geologic record’. Basically we’re looking beyond the historic record of scientific observations by reading what’s preserved in the landscape – what are sometimes described as ‘natural archives’. Nature has a fabulously diverse library and can include trees, corals and even ice cores. The real test is finding these ‘books’. As a result, the team work around the world unearthing new records.

One of our most recent projects is to reconstruct changing drought across eastern Australia and New Zealand over the last 500 years. When Australia experiences a drought, it can cause billions of dollars of environmental and economic damage. A classic example is the ‘Millennium…

The First Marine Park in the Antarctic

It’s taken more than five years of bruising negotiations but on Friday the Convention on the Conservation of Antarctic Marine Living Resources made the wonderful announcement that the Ross Sea will become the first ever Marine Protected Area in the south. In Hobart the European Union and 24 nations hammered out a deal that more than one million square kilometres – the largest remaining pristine marine ecosystem left on the planet – will be protected for at least 35 years, a first in international waters. The practical upshot is fishing will be banned in a region equivalent in size to the combined areas of France and Spain where one-third of the world's Adélie penguins, one third of all Antarctic petrels, and over half of all South Pacific Weddell seals live. This new marine park will create a vast natural laboratory for studying Antarctic life and the impacts of climate change. Perversely, a major stumbling block was Russian concerns over access for its fleet to catch the highly v…