Climate change models omit key component
University of Guelph | February 27, 2014
Climate models used to study temperature change from greenhouse gases are missing a key ingredient — economics, according to a new study by a University of Guelph professor.
Economist Ross McKitrick, an expert in environmental policy analysis, says most models ignore the effects of socioeconomic change on land use changes, making those models inaccurate.
The study, co-authored with Lise Tole of Strathclyde University, was published online in the journal Climate Dynamics.
McKitrick has studied how land use changes from urbanization, agriculture and other surface modifications affect temperature trends around the world. Past research suggests these effects might account for some of the warming patterns in weather data. Climate modelers assume that the effects are filtered out at the data processing stage, he said.
“As a result, when researchers look for explanations of regional patterns of climatic changes, they rule out things like urbanization by assumption and give greater weight to global factors like greenhouse gases and solar variations,” McKitrick said.
The study examined data from 22 sophisticated climate models used by the Intergovernmental Panel on Climate Change (IPCC). The researchers compared how accurately those models would have predicted spatial warming patterns over land between 1979 and 2002 with predictions from a much simpler model using data on regional industrialization and socioeconomic growth.
“The contrasts were striking,” McKitrick said. Twenty of the IPCC models made predictions that were no better than random guesses or that contradicted the observed patterns, he said.
“Only two of the 22 models showed any explanatory power for the temperature changes over the same period.”
By contrast, the simple economic model made much more accurate predictions.
Using various statistical techniques to compare modeling approaches, the researchers found that usually the economic model was essential and the climate model could be dropped, but never the other way around.
One technique involved searching more than 537 million combinations of climate model outputs and socioeconomic data for the best possible mix. The research team found that combining three of the 22 climate models and a small number of socioeconomic indicators best explained the spatial pattern of surface temperature trends.
“By assuming the socioeconomic effects are not there, a lot of climate researchers are ignoring a key feature of the data,” McKitrick said.
The researchers also found that the best climate models aren’t necessarily the most well-known ones. The best models came from labs in China and Russia and from one American institute; models from Canada, Japan, Europe and most U.S. research labs lacked explanatory power, either alone or in combination.
The study has important implications for policy-makers, McKitrick said. “Computer forecasts of regional climate changes between now and 2030 can look impressive in their detail, but it would be wise not to make major policy decisions without first looking into the model’s forecast accuracy.”
The findings are also important for researchers, especially those using climate data sets. “A lot of the current thinking about the causes of climate change relies on the assumption that the effects of land surface modification due to economic growth patterns have been filtered out of temperature data sets. But this assumption is not true.”
Originally published on June 20, 2012 by the University of Guelph. Ross McKitrick speaks at the What Matters Now event in Thunder Bay on March 4.
Cobalt Connects with James ...
Patchen Barss |Jeremy Freiburger is a “Cultural Strategist” who leads a Hamilton-based not-for-profit organization called Cobalt Connects. Working with McMaster researcher James Dunn, he’s putting theories about the relationship between the built environment and quality of life to the test. read more »
Mary Chaktsiris | November 20, 2014Can buying pigeons be a crime? In 1916, a seemingly routine act of receiving a crate of pigeons was misconstrued as an act of war. John Balasz, born in a country at war with the British Empire, was accused in Sault St. Marie of using the pigeons to carry unauthorized wartime messages. read more »
Polanyi Prize for Literature: ...
COU Staff | November 17, 2014In modern times, alarmist visions of a grey tsunami of retirees, a lost generation of unemployed young people and a theorized war against youth have been warning global audiences that people of different age groups are simply incompatible. Andrea Charise’s research examines how the generational identity and intergenerational conflict that’s evident today was represented much earlier in literature. In fact, in 19th-century British literature and culture, older age was being reconceived, not only in literature but also as a field for health-based research. Today, we are told to do the Sudoku and exercise our body to keep ourselves young, but aging and the notion that we must keep our body and mind in perpetual motion is a late 18th-century way of thinking about the body. Charise’s research also examines the politics and poetics of generational relations in 19th--century Britain, which again surface in modern times. The conflict between the generations was evident in literary texts as far back as Oedipus Rex and King Lear, but in 1798, British economist Thomas Malthus set off a culture war when he blamed the potential catastrophe of overpopulation on the thriving reproductive capacities of young people. In modern times, Charise says the defining of age-based groups such as Boomers and Millenials is evidence of generational identity and intergenerational conflict in the modern literary imagination. Literature and the humanities, her research concludes, are crucial to communicating in accessible ways the consequences of the way we think about age and the way generations think about each other. Andrea Charise, Assistant Professor of Health Studies, University of Toronto, Scarborough wins the Polanyi Prize for Literature.