STAR-BULLETIN / FEBRUARY 2001
UH researcher Axel Timmermann is a specialist on Earth's climate. He studies the climate change differences between the Northern and Southern hemispheres during the last ice age. CLICK FOR LARGE
Hemisphere of influence
A UH researcher wins an award for his work in paleoclimatology
A University of Hawaii researcher who is trying to figure out what caused abrupt climate changes in the last ice age has received the prestigious Rosenstiel Award in Oceanographic Science.
Axel Timmermann, 36, associate professor of oceanography and research team leader at the International Pacific Research Center, was honored for his "outstanding achievement and growing impact on ocean sciences."
The award, consisting of a gold medal and $10,000, will be presented to the climate scientist at a banquet this spring at the University of Miami's Rosenstiel School of Marine and Atmospheric Science.
"I was really very surprised and honored," Timmermann said in an interview, explaining he did not apply for the award.
"Being in the midst of Klaus (Wyrtki) is a great honor," he said. The Rosenstiel Award in 1981 went to Wyrtki, the retired UH oceanography professor whose pioneering research led to the understanding and forecasting of El Nino events.
Timmermann earned a doctorate degree in theoretical physics at the Max Planck Institute of Meteorology in Hamburg, Germany. He was a visiting assistant researcher at the International Pacific Research Center, UH School of Ocean & Earth Science & Technology, from October 2000 to March 2001. He left to lead a research group at the University of Kiel and returned to UH in August 2004.
Timmermann does paleoclimatology research, studying climate changes over hundreds of thousands of years. He uses data from ice cores to validate computer models.
The fastest climate transitions people ever observed occurred in the last glacial period, which ended about 10,000 years ago, he said.
Within 10 years the climate system in the Northern Hemisphere switched from a cold state to a warm state, he said. It remained warm for about 1,000 years, then plunged back into a cold glacial state, he said.
Nobody fully understands why that happened, he said.
Another question is why the climate system shifted from the ice age in the Southern Hemisphere about 18,000 years ago, Timmermann said.
The climate warmed steadily until about 10,000 years ago, then stayed on a constant level, he explained.
The puzzle is why the Antarctic, or Southern Hemisphere, warmed at the same time as the Northern Hemisphere, he added.
One reason was carbon dioxide, which began increasing in the atmosphere about 16,000 years ago, warming both the Northern and Southern hemispheres, he said.
But warming in the Southern Hemisphere began earlier than the rise in carbon dioxide, he said. "So there must be another reason for this warming."
One theory is that changes in Earth's orbit significantly affected incoming solar radiation in springtime 18,000 years ago, he said.
Learning about these changes "gives us a way of calibrating our models more accurately for future climate change projections and also gives us an opportunity to understand how the climate system operates," Timmermann said.
"Also, we learn something about the potential for abrupt climate change and the question of how fast sea level can rise."
Abrupt climate changes in the last ice age were associated with sea level rise of 66 to 90 feet, he said.
"Nobody really knows how fast that sea level rise was. Maybe it took 200 to 1,000 years. Even 1,000 years, 90 feet is large."