January 8, 2010

Return to the White Continent

On January 3, Queens College geologist STEPHEN PEKAR arrived in Wellington, New Zealand, to join 32 other scientists from around the world on an expedition they hope will begin to unlock some spectacular secrets about the world’s past—and maybe about its future. As a specialist in “paleoceanography,” Pekar has spent the last several years investigating  climate and oceanographic changes in the period—between 16 and 45 million years ago—when high concentrations of carbon dioxide caused the earth to be in what scientists call its Greenhouse World time.

Now, Pekar is  on the expedition of his career: A two-month journey with a prestigious international marine research group, the Integrated Ocean Drilling Program (IODP). The organization, whose governing body includes the National Science Foundation, brings together top scientists from around the world to explore the earth’s history and structure by drilling through the ocean floor and recovering sediments deposited millions of years ago. The Antarctic mission is called Expedition 318: Wilkes Land. It is the IODP’s first exploration under Antarctica in 10 years.

A filmmaker’s preview of Expedition 318
About the Integrated Ocean Drilling Program (IODP)

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WELLINGTON, New Zealand, January 7 | It is the beginning of another Antarctic adventure, my fourth to this continent of frozen wilderness and raw beauty and of endless potential for discovery of the unknown. I’ve been to 40 countries, but no place on earth has enchanted me like Antarctica. It is a land without mercy, breathing fierce winds that ravage the great mounds of snow and iridescent-colored ice. It is a strange and bewitching place, barely resembling anything anywhere else on earth.

But we’re not there yet; not even close. Even once we board our ship, the gargantuan research vessel JOIDES Resolution, we’ll have more than a week on the high seas before we reach our research site. We’ll anchor about 30 miles off the Antarctic coast and spend the next two months drilling way down and far back: We’ll go some 12,000 feet through the water and then nearly three-quarters of a mile beneath the ocean floor, bringing up sedimentary samples and microfossils that could be pieces of a puzzle for the ages–archives of Antarctic climate change perhaps as old as 50 million years. With our long journey south ahead, there will be plenty of time to reflect and tell you about the adventure that awaits us. For now, some essential background on Expedition 318.

Steve on ship before departure

There is no more fascinating a place than Antarctica to study and think about climate change. Through millions of years, it has sometimes occurred there in abrupt spurts, other times more gradually. In either event, there is no question that climate change has been more dramatic on Antarctica than in any other place in the world. Just realize that it was once a continent of lush hills and forests and you understand why it is climate change’s Ground Zero.

So what tremendous force burned the forests with frost and covered those verdant hills with towering mounds of ice? It wasn’t some mighty volcano or forces from deep below the Earth that moved the continent to the most southern reaches of this planet.  No, it is far more subtle. In fact, it is so elusive that one cannot touch it or see it, and it has little power of its own. Yet it has changed climate on a planetary scale and the course of evolution for billions of years. It is the odorless, colorless essences that we call greenhouse gases.  In this case, the hero of this climate revolution is changes in carbon dioxide.  For whatever reasons, we homo sapiens evolved during the earth’s lowest levels of CO2. We have no knowledge or conception of an earth with elevated carbon dioxide. We have built our civilizations around this cooler planet.  A warmer earth would raise sea levels higher than most cities and turn agriculture into desert.

Wilkes Land

The route of Expedition 318: On January 8, the JOIDES Resolution departs Wellington, New Zealand (top right), the start of an eight-day, 2,000-mile journey south to its research site off the coast of Antarctica. After collecting data for eight weeks, the team will sail back to civilization, arriving in Hobart, Australia (left) on March 9.

The focus of Expedition 318 is the transition from the Greenhouse World to the Icehouse World—a time believed to be about 33 million years ago. Our destination is a site just off the coast of East Antarctica, an area named Wilkes Land for the nineteenth century American explorer Charles Wilkes, one of the first people to set eyes on the Antarctic continent.What makes recovering cores from that area so important is that climate models suggest that Wilkes Land was among the last areas of East Antarctica to become glaciated, making it the most sensitive to climate changes in the past as well as more vulnerable to future climate change.

Therefore, Wilkes Land becomes critical in understanding the evolution of the East Antarctic Ice Sheet, and it can help address some long-pondered  questions: What was Antarctica like during the Greenhouse World?  (The Earth was much warmer than today, and the limited evidence from sites far from Antarctica suggests that Antarctica was covered by a vast forest, with perhaps small, ephemeral glacial ice high on Antarctica’s plateau.) What caused the abrupt climate shift of 34 million years ago, the most fundamental reorganization of the climate system in the earth’s history? Why did it change so dramatically? How large did the ice sheets get?  And what was the link between ice sheet growth and global cooling and greenhouse gases?

A growing body of knowledge indicates that climate changes are due to increased concentrations of greenhouse gases such as CO2 in our atmosphere. There are projections for atmospheric CO2 levels to rise to levels last seen 25 million years ago.

Clearly, a better understanding of the evolution of Antarctic ice sheet and its climate is needed for these critical time intervals when climatic tipping points occurred. However, a paucity of data currently exists from near or on the Antarctic continent. This is due in part to the difficulty in conducting an expedition in this cold harsh region. In fact, many scientists now agree that the key to the climate puzzle lies literally at the bottom of the Earth: Antarctica. However, so far only one continuous core was recovered on the Antarctic continent or on its shelf from when the Earth was in a Greenhouse World and it penetrated only about 2 million years in the latest part of the Greenhouse World. So for many Antarctic scientists, recovering sediments from this period is considered one of the holiest of holy grails.