[Note: I have tried to link to the relevant literature on extreme precipitation trends. If I've missed any, let me know.]
“I actually think the science around climate change is real. It is potentially devastating,” Obama told reporters Monday. “If you look at the flooding that’s going on right now in North Dakota and you say to yourself, ‘If you see an increase of two degrees, what does that do, in terms of the situation there?’ That indicates the degree to which we have to take this seriously.“
Besides Obama, the British and the Chinese understand global warming has driven their record flooding. The United States media? Not so much.
Certainly North Dakota is experience record-breaking flooding:
So wrote Noreen Schwein, water program director at National Weather Service central region headquarters. Fargo’s mayor calls the flooding “uncharted territory.”
But you’ll have to look very hard to find a single story in the mainstream media that even mentions climate change (other than the few quoting our President) — even though the record “once-in-a-hundred-year flooding” the Midwest now seems to be getting every few years or so is precisely what scientists have been expecting from the warming [see "Global warming causes deluges and flooding, just like the Midwest is seeing (again)."]
In fact, in 2004, the Journal of Hydrometeorology published an analysis by NOAA’s National Climatic Data Center that found “Over the contiguous United States, precipitation, temperature, streamflow, and heavy and very heavy precipitation have increased during the twentieth century.” [And yes, this applies to snow, depending on the location, see below.]
They found (here) that over the course of the 20th century, the “Cold season (October through April),” saw a 16% increase in “heavy” precipitation events (roughly greater than 2 inches [when it comes as rain] in one day), and a 25% increase in “very heavy” precipitation events (roughly greater than 4 inches in one day)– and a 36% rise in “extreme” precipitation events (those in the 99.9% percentile — 1 in 1000 events). This rise in extreme precipitation is precisely what is predicted by global warming models in the scientific literature.
In fact, the last few decades have seen rising extreme precipitation over the United States in the historical record, according to NCDC’s Climate Extremes Index (CEI):
Here is a plot of the percentage of this country (times two) with much greater than normal proportion of precipitation derived from extreme 1-day precipitation events (where extreme equals the highest tenth percentile of deluges, click to enlarge):
Didn’t know that our government kept a Climate Extremes Index? Why would you? The media never writes about it.
The U.S. Climate Extremes Index was explicitly created to take a complicated subject (“multivariate and multidimensional climate changes in the United States“) and make it more easily understood by American citizens and policy makers. As far back as 1995, analysis by the National Climatic Data Center showed that over the course of the 20th century, the United States had suffered a statistically significant increase in a variety of extreme weather events, the very ones you would expect from global warming, such as more — and more intense — precipitation. That analysis concluded the chances were only “5 to 10 percent” this increase was due to factors other than global warming, such as “natural climate variability.” And since 1995, the climate has gotten much more extreme.
Even the Bush Administration in its must-read U.S. Climate Change Science Program report, Weather and Climate Extremes in a Changing Climate, acknowledged:
Many extremes and their associated impacts are now changing…. Heavy downpours have become more frequent and intense….
It is well established through formal attribution studies that the global warming of the past 50 years is due primarily to human-induced increases in heat-trapping gases.… The increase in heavy precipitation events is associated with an increase in water vapor, and the latter has been attributed to human-induced warming.
One more key point: Because this flooding involves snow — and because some global warming doubters seem to think that every snowstorm is proof global warming isn’t occuring — let me just make the obvious point. With the increase in “cold season” precipitation and extreme precipitation, you would expect that it comes down as snow where it is cold, but less so where it is warm.
A 2005 study, coauthored by NCDC, “Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States,” found:
The temporal distribution of snowstorms exhibited wide fluctuations during 1901–2000, with downward 100-yr trends in the lower Midwest, South, and West Coast. Upward trends occurred in the upper Midwest, East, and Northeast, and the national trend for 1901–2000 was upward, corresponding to trends in strong cyclonic activity.
We have seen more snow overall and especially in the places where it is the coldest. Obviously, global warming has warmed “threshold” or more southern locations enough to turn many snowstorms into rain or ice storms.
Finally, if you are a journalist wondering what is a reasonable way to talk about this, one of the best recent examples comes from a New York Times story on Australia made possible by our friend Andrew Revkin:
The firestorms and heat in the south revived discussions in Australia of whether human-caused global warming was contributing to the continent’s climate woes of late — including recent prolonged drought in some places and severe flooding last week in Queensland, in the northeast.
Climate scientists say that no single rare event like the deadly heat wave or fires can be attributed to global warming, but the chances of experiencing such conditions are rising along with the temperature. In 2007, Australia’s national science agency published a 147-page report on projected climate changes, concluding, among other things, that “high-fire-danger weather is likely to increase in the southeast.”
The flooding in the northeast and the combustible conditions in the south were consistent with what is forecast as a result of recent shifts in climate patterns linked to rising concentrations of greenhouse gases, said Kevin Trenberth, a scientist at the United States National Center for Atmospheric Research.
That’s how it is done.
And no, I’m not say that the media should link every extreme weather event the way Revkin did. But when we have “worst on record” type events, or 100-year floods — and especially ones that last more than a day and hit a broad area — then I think the reporter has an obligation to include the issue.
- Why do the deniers try to shout down any talk of a link between climate change and extreme weather?
- Pielke in Nature: “Clearly, since 1970 climate change … has shaped the disaster loss record.”
- Sorry, deniers & delayers, Part 1: Even U.S gov says human emissions are changing the climate
- Sorry, delayers & enablers, Part 2: Climate change means worse droughts for SW and world
- Record Flooding Slams Midwest (2007)
- Global warming will spawn severe storms and tornados, reports NASA
- Early 2007 saw record-breaking extreme weather
- A deluge of extreme weather, thanks to climate change
- Apr¨s nous le deluge
- UK Prime Minister on “weather extremes” and climate change
- UK: Worst Floods In Modern History
- NBC Reports on Hell and High Water
- ABC Reports on Hell and High Water
- The Weather IS Becoming More Extreme