SAN FRANCISCO -- Scientists affiliated with the U.N. Intergovernmental Panel on Climate Change (IPCC) highlighted areas for future scientific focus during a presentation at the American Geophysical Union conference here.

Researchers would like to improve observations of the planet, particularly in the oceans and at the poles; reduce uncertainties about clouds, aerosols and climate; and better understand the cycling of carbon through the Earth's systems, the scientists said.

In contrast, scientists are very sure about the role of humans in global warming and that the Earth is warming, said Thomas Stocker, who co-chairs the IPCC's Working Group I, which released an update on the science of climate change in early October.

"Human influence on the climate system is clear," he said. "Limiting climate change will require substantial and sustained reductions of greenhouse gases."

Dennis Hartmann, a researcher at the University of Washington who coordinated the IPCC chapter on observations, outlined issues that need more study: "The Arctic sea ice has declined much more rapidly than most of the models predict, and yet in the Antarctic the sea ice has been increasing for the last decade of time."

A longer record of observations in the oceans might also help scientists better understand natural variability and the causes of the so-called warming pause or hiatus, where surface temperatures have not risen over the past decade or so, Hartmann added.

According to recent research, one reason the Earth's surface temperatures may not appear to be warming is that observations in the Arctic, which is warming rapidly, are scarce and thus underrepresented in the data (ClimateWire, Nov. 18).

The effects of aerosols, which have a cooling effect on the planet, and clouds, which can either warm or cool, are also still a big source of uncertainty when researchers are trying to determine how sensitive the Earth's climate system is to changes in greenhouse gases.

Unanswered question include IPCC's future
"The new frontier in clouds is to understand links between clouds, atmospheric circulation and how this relates to climate sensitivity," said Olivier Boucher, a scientist who was the coordinating lead author of the IPCC chapter on clouds and aerosols.

While the IPCC scientists focused on presenting areas of scientific interest, they were repeatedly asked about the future of the panel and its reports.

In recent years, some scientists have called for changing the IPCC so it no longer produces large assessment reports every six or seven years and rather produces short, targeted reports on topics of interest (ClimateWire, Oct. 7).

"I think it's too early to respond to that question, and that question will be responded to by the Intergovernmental Panel on Climate Change," Stocker said. The IPCC Bureau, which makes decisions about the panel's trajectory, next meets in late February.

Stocker acknowledged that IPCC scientists, who volunteer their time and who analyzed more than 2 gigabytes of data and responded to more than 54,000 review comments for this latest report, were growing weary.

"The sheer amount of data that has to be analyzed ... it's just a big task and a big burden to the scientific community, and it has come really to the limits."

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC., 202-628-6500