Summary: The heavy rains hitting Texas last May were record-breaking extreme weather evens. But were they natural (records routinely break as time passes) or the result — partially or mostly — the result of anthropogenic effects? Here an eminent climatologist gives a preliminary answer, based on solid evidence (not modeling). There is no visible trend to rainfall in Texas, but its distribution has changed — more concentrated in large storms.
“With the lack of a positive trend in monthly springtime precipitation, there is no direct observational evidence that the record-setting May 2015 statewide rainfall total in Texas had an anthropogenic component.”
The mainstream news media have become more cautious in their coverage of extreme weather, unlike their previous uncritical reporting of everything as climate change. For example, see this by USA Today: “Wild weather shifts in Texas spark concern about “new normal’.” And “Climate Change May Have Souped Up Record-Breaking Texas Deluge” by Elizabeth Harball and Scott Detrow at Scientific American on 27 May 2015 — “Deadly downpours flooded Texas and Oklahoma and may have been exacerbated by global warming.” The link to climate change is strongly implied, but not stated as definite. The text reports climate scientists’ uncertainty about attribution of events to climate change.
Activists ignore the science, preferring simple narratives. Bill Nye, the children’s science guy, says on CNN: “The floods in Texas, the strengthening storms… these things are a result of human activity making things worse.” As usual, the most over-the-top story comes from fantasy writer – climate activist Robert Marston Fanney (bio here) at his blog RobertScribbler: “The Merciless Rains of Climate Change Hammer Houston, Southeast Texas.”
Eventually scientists will produce papers with more definitive information. Here’s an excerpt from an early analysis (click on the link to read it in full)…
By John W. Nielsen-Gammon (see his bio)
Texas state climatologist and professor of atmospheric sciences at Texas A&M
From NOAA’s Annual Climate Diagnostics and Prediction Workshop, Oct 2015
Texas received its all-time wettest month of rainfall in May 2015, with an average of 9.05″ (230 mm) across the state… The purpose of this talk is to put the extreme rainfall events in Texas in 2015 in a historical perspective and to consider the possible role of contributing factors, including anthropogenic climate change …