Many biologists who are studying the potential impacts of climate change on different species and the environment could be coming to faulty conclusions unless they widen the scope of their research, a new Canadian study suggests.The report, published in Global Change Biology, suggests biologists often use only one of the 31 different climate-change models provided by the Intergovernmental Panel on Climate Change (IPCC).
Those models, while generally consistent at predicting climate, can differ significantly in providing data about how the living conditions for certain species are expected to change, the study found.
Co-author Jonathan Newman, a professor of environmental biology at the University of Guelph, was researching the impact of climate change on the swede midge, an invasive insect that has been affecting canola crops in the United States since 1996 and has now migrated to southern Ontario.
Newman’s team used two models and expected some level of variation in the results. But they did not expect contradictory data.
“We basically got opposite answers when we should have gotten the same answer,” Newman said.
“What we’ve shown is if you use more than one model you can get entirely different results, so (based on studies that used only one model) maybe we have no view at all of what the impacts are going to be.”
A Canadian climate model found the swede midge could expand across Ontario and into northern and western regions of Canada and the United States due to warmer and moist conditions brought on by climate change.
But a British model—one of the most commonly used by researchers—found that ideal conditions for the swede midge would disappear significantly with climate change, which surprised Newman.
“That was worrying as a biologist engaged in the business of trying to elucidate biological impacts,” he said. “What we need is a whole array of models that all make different assumptions and then we look for conclusions that are reasonably robust.”
Of the 65 studies that have used the IPCC models since 1994, only about one in five used more than one model, the report found.
It doesn’t mean that the existing research is wrong, Newman said, but scientists should be working with multiple models so they can be certain about their results.
“I certainly would hope that (the study) spurs more research like we’ve been doing in our lab,” he said.
There’s no debating that researchers should be using multiple models and variables in their research and it’s not very surprising that some contradictions could emerge, said Quentin Chiotti, lead author of the Ontario chapter of Natural Resources Canada’s recent report, “From Impacts to Adaptation: Canada in a Changing Climate 2007.”
“If there’s a lesson to be learned based on this article, that would be to use a wide range of models and a wide range of scenarios; fair enough, I don’t know how you could try to refute that,” he said.
But he also questioned just how serious the problem is and said most top-level research and work by policy-makers would be very thorough.
There are many studies that only use one model and are taken seriously, but researchers should always be taking that factor into account, he said.
“It’s our job to look at the literature with a critical eye and get a sense of what were they really using and what were they really saying. It’s really up to the scientists to determine what are the most plausible outcomes, where can we make—from a precautionary-principle perspective—the most intelligent decisions.”
Elaine Wheaton, who also contributed to the Natural Resources Canada report, said the study makes a valid point in highlighting that research should always use multiple models.
“It’s important because it tells us there is a risk (in using just one model). It’s quite true that you should have different approaches and methods; it just makes the results more robust,” said Wheaton, of the Saskatchewan Research Council.
“(Using one model is) certainly not recommended because it only gives one picture of the future, and more alert researchers would say it would be highly recommended to repeat the same sort of procedure with another global climate model.”
– The Canadian Press