You Ought to Have a Look: Natural Climate Variability
By Paul Homewood
While Al Gore is blaming the Louisiana floods on global warming, Michaels and Knappenberger introduce some inconvenient facts:
We’ve got a lot cover this week, so let’s get right to it.
On the science front, we want to highlight two new papers that both suggest that attributing heavy precipitation events in the United States to human-caused climate change is a fool’s errand (not that there aren’t plenty of fools running around out there). This is a timely topic to explore with the big rains in Louisiana over the weekend leading the news coverage.
One paper by a research team from the University of Iowa found that “the stronger storms are not getting stronger” and that there has not been any change in the seasonality of heavy rainfall events by examining trends in the magnitude, frequency, and seasonality of heavy rainfall events in the United States. They did report that the frequency of heavy rain events was increasing across much of the United States, with the exception of the Northwest. As to the reason behind the observed patterns, the authors write “[o]ur findings indicate that the climate variability of both the Atlantic and Pacific Oceans can exert a large control on the precipitation frequency and magnitude over the contiguous USA.”
The other paper, from a research team led by NOAA/GFDL’s Karin van der Wiel, examined climate model projections and observed trends in heavy precipitation events across the United States and concludes:
Finally, the observed record and historical model experiments were used to investigate changes in the recent past. In part because of large intrinsic variability, no evidence was found for changes in extreme precipitation attributable to climate change in the available observed record.
Pretty emphatic and straightforward summary.
So, the next time you read that such and such extreme precipitation event was made worse by global warming, you’ll know that there is precious little actual science to back that up.
We’ll note that the more astute science writers are actually familiar with findings like these but rather than fess-up about them, they prefer to further the climate change narrative through the use of weasel words like “is consistent with” expectations from climate change. This particularly useful phrase encompasses virtually all possibilities and allows every weather event to be linked to the nefarious burning of fossil fuels. And we do mean every—bad or good. But in practice, it is reserved by the media to be applied only to bad events or trends. For good-seeming goings-on, “dumb luck” is the preferred descriptor, despite plenty of science that could be used to show that good things, too, “are consistent with climate change expectations.” Go figure.