IMAGe hosts 2016 IDAG meeting at NCAR

By Brian Bevirt
06/30/2016 - 3:45pm
2016 IDAG participants
Participants in the 2016 annual meeting of the International Detection and Attribution Group. (Photo by Brian Bevirt, CISL)

In early 2016, CISL’s Institute for Mathematics Applied to Geosciences (IMAGe) hosted the yearly meeting of the International Detection and Attribution Group (IDAG). IDAG scientists specialize in identifying specific changes in the Earth’s climate and the factors that cause those changes. More specifically, they demonstrate that an observed change in climate significantly differs from natural variability (detection), then they identify the causes of that change (attribution). In addition to large-scale, long-term trends, a recent research direction within Detection and Attribution explicitly addresses the causes of specific extreme events in the news, making the value of the research much more tangible and memorable than careful statements about broad trends.

This 21-member core group of investigators has been collaborating since 1995 to assess and reduce uncertainties in scientific estimates of climate change. In that time, they have contributed substantially to the second, third, fourth, and fifth assessment reports of the United Nations’ Intergovernmental Panel on Climate Change (IPCC). In addition, they have made contributions to the United States Global Change Research Program (USGCRP, formerly the U.S. Climate Change Science Program).

For the meeting in Boulder, a total of 55 climate science experts from around the world spent four days presenting research updates, sharing insights, debating issues, and collaborating on strategies for using existing and upcoming resources to produce more detailed studies and reports. You are encouraged to review their presentations from the 2016 IDAG meeting.

In its early work, the group primarily focused on detection and attribution of global temperature changes. In recent years, their studies are shifting to subcontinental scales and variables other than temperature: “A significant influence of anthropogenic forcing has been detected in global- and continental-scale surface temperature, temperature of the free atmosphere, and global ocean heat uptake. ... The detection of changes in variables other than temperature, on regional scales and in climate extremes, is important for evaluating model simulations of changes in societally relevant scales and variables. ... To evaluate climate change signals with smaller spatial and temporal scales, improved and more densely sampled data are needed in both the atmosphere and ocean. Also, the problem of how model-simulated climate extremes can be compared to station-based observations needs to be addressed.” Cited from Hegerl, Gabriele C., T.R. Karl, M. Allen, N.L. Bindoff, N. Gillett, D. Karoly, X. Zhang, F. Zwiers (2006): Climate change detection and attribution: beyond mean temperature signals. Journal of Climate, 19(20), 5058-5077. doi:10.1175/JCLI3900.1

IDAG poster session
The IDAG welcomes contributions and new ideas from early-career researchers, and the poster session provided an opportunity for them to exchange ideas with senior scientists. (Photo by Brian Bevirt, CISL)

The group’s research activities now involve the assessment of climate change impacts. Under investigation are impacts on society that include property damage and health effects from changes in droughts, floods, and the transmission of infectious diseases. A broad overview of impacts includes “...physical systems (such as rivers and ice-sheets), biological systems (such as forests, grasslands, marine biota), social systems (such as cultural values, governance practices, and livelihoods) and economic systems (such as the production of goods and services)....” Cited from Stone, D., M. Auffhammer, M. Carey, G. Hansen, C. Huggel, W. Cramer, D. Lobell, U. Molau, A. Solow, L. Tibig, and G. Yohe (2013): The challenge to detect and attribute effects of climate change on human and natural systems. Climatic Change, 121(2), 381-395. doi:10.1007/s10584-013-0873-6

Each year, more detection and attribution studies are focusing on changes in extreme events and their impacts on society and the ecosystem. The rarity of extreme events makes them harder to study and requires deeper statistical analysis. Some IDAG members are interested in developing new methods for pursuing these investigations, and some are investigating statistical methods that will allow extreme events to be reliably attributed to climate change. The IDAG’s interest in extremes dovetails well with IMAGe’s 2015-2016 Theme of the Year, Extremes in Climate Sciences: A Statistical, Dynamical and Machine Learning Inquiry, chaired by Philippe Naveau, a climate researcher using applied math and statistics and a specialist in Extreme Value Theory.

A discussion between meeting sessions
Lively discussions took place between presentations and other meeting sessions. (Photo by Brian Bevirt, CISL)