The Midwest has experienced near record flooding this spring, resulting in four deaths, extensive property damage, and disruptions of agriculture and transportation. Evidence suggests that manmade climate change has increased the frequency of heavy downpours, and will continue to increase flooding risks. But in their ample coverage of Midwestern flooding, major media outlets rarely mentioned climate change.
Less Than 3 Percent Of Midwest Flood Stories Mention Climate Change
ABC, NBC And CNN Entirely Ignore Climate Connection. ABC, CBS, NBC and CNN devoted 74 full segments to flooding in the Midwest, but only one -- on CBS Evening News -- alluded to the fact that heavy downpours have increased (one percent of coverage). That segment did not explain that scientists have attributed this to climate change, and did not feature any scientists. MSNBC and Fox News were not included in this analysis because transcripts of their daytime coverage are not available in Nexis. [CBS News, 5/2/13]
USA TODAY Only National Print Outlet To Mention Climate Context Of Floods. USA TODAY, which recently launched a year-long series on the impacts of climate change, was the only national print outlet in our study that mentioned climate change in its reporting on Midwestern floods. The Associated Press, Reuters, Los Angeles Times, New York Times, and Wall Street Journal never mentioned climate change in a total of 35 articles on the floods. The Washington Post did not cover the flooding independently. In total, only 3 percent of national print coverage mentioned climate change. [USA TODAY, 4/22/13] [Media Matters, 3/1/13]
Local Media Largely Ignore Climate Context Of Floods. Less than 4 percent of local newspaper articles on flooding in the Midwest mentioned climate change -- only 4 of 107 articles. The Kansas City Star, Des Moines Register, Detroit Free Press, Minneapolis Star-Tribune and Indianapolis Star never made that connection. Flooding in the area has nearly surpassed records, leading to four deaths, delays in planting agriculture, disruptions in transportation, and potential health impacts. [The Atlantic Wire, 4/25/13] [Union of Concerned Scientists, 4/30/13] [Climate Central, 4/26/13]
No Coverage Of Flooding Contribution To The Gulf “Dead Zone.” Aquatic ecologist Don Scavia told Media Matters in an email that “most media coverage is missing an important aspect of such flooding. These massive spring flooding events push an enormous amount of agricultural pollution down the Mississippi system and into the Gulf of Mexico. That flux will most certainly create a large dead zone.” He added that conservation policies for farmers “may no longer be adequate” as flooding risks increase from climate change. Indeed, our study found that aside from one article in the Des Moines Register, the media overlooked that flooding increases fertilizer runoff from Midwestern farms into the Gulf of Mexico, further contributing to the “dead zone” there. [UPI, 4/10/13]
Evidence Suggests Climate Change Worsens Flood Risks In Midwest
Warming Leads To More Overall Precipitation. As the Environmental Protection Agency explained, basic physics indicates that warming leads to more evaporation and thus more precipitation overall:
As average temperatures at the Earth's surface rise (see the U.S. and Global Temperature indicator), more evaporation occurs, which, in turn, increases overall precipitation. Therefore, a warming climate is expected to increase precipitation in many areas. However, just as precipitation patterns vary across the world, so will the effects of climate change. By shifting the wind patterns and ocean currents that drive the world's climate system, climate change will also cause some areas to experience decreased precipitation. In addition, higher temperatures lead to more evaporation, so increased precipitation will not necessarily increase the amount of water available for drinking, irrigation, and industry."
The EPA created this map, based on 2012 data from the National Oceanic and Atmospheric Administration, showing that precipitation in most areas of the U.S. including the Midwest has increased over the last century:
[Environmental Protection Agency, accessed 5/1/13]
Frequency Of Large Rain Storms Has Increased In The Midwest. An analysis by the Rocky Mountain Climate Organization found that the “frequencies of all large storms, especially the largest, jumped in recent years” in the Midwest:
Since 1961, the Midwest has had an increasing number of large storms. The largest of storms, those of three inches or more of precipitation in a single day, increased the most, with their annual frequency having more than doubled over the 51 years. The frequencies of all large storms, especially the largest, jumped the most in recent years.
These are the central conclusions of a new analysis by the Rocky Mountain Climate Organization (RMCO) of precipitation in the eight midwestern states of Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, and Wisconsin. The data are from 218 weather stations in the U.S. Historical Climatology Network (USHCN), the nation's most reliable weather stations.
The analysis included the following chart:
[Rocky Mountain Climate Organization in collaboration with the Natural Resources Defense Council, May 2012]
Increase In Worldwide Precipitation Has Been Attributed To Human Influences. The New York Times reported in 2011:
An increase in heavy precipitation that has afflicted many countries is at least partly a consequence of human influence on the atmosphere, climate scientists reported in a new study.
In the first major paper of its kind, the researchers used elaborate computer programs that simulate the climate to analyze whether the rise in severe rainstorms, heavy snowfalls and similar events could be explained by natural variability in the atmosphere. They found that it could not, and that the increase made sense only when the computers factored in the effects of greenhouse gases released by human activities like the burning of fossil fuels.
Scientists have long been reluctant to attribute any specific weather event to global warming, but a handful of papers that do so are beginning to appear in the scientific literature. One such installment is being published on Thursday in Nature as a companion piece to the broader paper. It finds that severe rains that flooded England and Wales in 2000, the wettest autumn since record-keeping began there in 1766, were made substantially more likely by the greenhouse gases released by human activity. [New York Times, 2/16/11]
Climate Models Indicate That Heavy Downpours Will Increase In Midwest. The 2009 National Climate Assessment stated that climate models have projected that the heaviest downpours will increase in North America, particularly in the Midwest and Northeast:
Climate models project continued increases in the heaviest downpours during this century, while the lightest precipitation is projected to decrease. Heavy downpours that are now 1-in-20-year occurrences are projected to occur about every 4 to 15 years by the end of this century, depending on location, and the intensity of heavy downpours is also expected to increase. The 1-in-20-year heavy downpour is expected to be between 10 and 25 percent heavier by the end of the century than it is now.
[T]he Midwest and Northeast, where total precipitation is expected to increase the most, would also experience the largest increases in heavy precipitation events.
A more recent draft National Climate Assessment similarly found that in the Midwest "[e]xtreme rainfall events and flooding have increased during the last century, and these trends are expected to continue, causing erosion, declining water quality, and negative impacts on transportation, agriculture, human health, and infrastructure." That report included the following map showing the heaviest precipitation (top 2 percent of all rainfalls) is projected to increase by 2041-2070 relative to 1971-2000:
The 2009 report also included the following chart showing that the heavy rainfall is projected to increase compared to 1990s averages, based on climate models used in the IPCC's 2007 assessment report:
Uncertainties Remain About Future Precipitation Patterns. The University of Iowa's page on the “impacts of global climate change on the Midwest” cautions that precipitation projections are more complicated than temperature projections:
Precipitation is much more difficult for climate models to simulate [than temperature]. So we have less confidence in the predictions of changes in precipitation due to climate change (more “mediums” and fewer “highs” in the confidence levels). A complicating issue of assessing changes in precipitation in the Midwest is that we are located close to regions of high precipitation gradients. That is, annual precipitation is much less in western Iowa than eastern Iowa and less in northern Iowa than southern Iowa. In Illinois, there is less in the north than the south, but east-west differences are small. So if precipitation patterns shift eastward, for instance, in a future climate, Iowa will be more affected than Illinois, but both will be affected by a northward shift of higher rainfall. [University of Iowa, accessed 5/1/13]
However, Experts Warn It Is “Irresponsible” To Let Uncertainties Delay Adaptation. A report on “Flood Management In A Changing Climate” by the World Meteorological Organization and the Global Water Partnership warned policymakers and municipal authorities against letting uncertainties delay adaptation:
[T]he scientific knowledge about the climate change and its impacts on the hydro-meteorological extremes such as floods and droughts is far from fully understood thereby making it difficult to assess future risks. Due to this uncertainty; managers can no longer have confidence in single projections of the future. It will also be difficult to detect a clear climate change effect within the next couple of decades, even with an underlying trend. Therefore, use of an adaptive management strategy is essential.
However, it is an irresponsible strategy to wait for less uncertain assessments before implementing adaptation measures, since climate change and its impacts are already taking place. Furthermore, waiting for less uncertain scenarios is a treacherous hope; the results will remain uncertain in future even with increased refinement of scientific methods. [World Meteorological Organization and the Global Water Partnership, August 2009]
Experts Urge Journalists To Incorporate Climate Change Into Flood Coverage
Seven Out Of Eight Scientists Agreed It Is Apt To Mention Climate Change In Flood Coverage. Of eight scientists who responded to inquiries from Media Matters, seven agreed that it is “appropriate” or “advisable” for journalists to explain how manmade climate change could worsen flood risks in the Midwestern United States. One emphasized uncertainty about future precipitation patterns.
Scavia: Media Are “Missing” That This Is The “New Normal.” When told of the preliminary results of our analysis, Don Scavia, an aquatic ecologist at the University of Michigan and a lead convening author of the Midwest chapter of the draft National Climate Assessment, stated, “I think they're missing an important piece of information and if you don't make the point that these intense storms are occurring more often, each one looks like a one off event.” He said that if you mention the historical trend, “you get a better sense of whether these are just rare and unusual events or a new normal, which is what they really are.” He stated that in his view, “it's been actually good to see some of the reporting, such as on The Weather Channel, talk about how these storms are consistent with climate models -- in the past, they never made those observations.” Scavia added that this “new normal” “should influence policies associated with building and development, ”such as FEMA (Federal Emergency Management Agency) flood plain maps that affect insurance rates and building codes. [Phone conversation, 5/6/13]
Oppenheimer: It Is “Advisable” For The Press To Mention Climate Change Connection. In a phone conversation with Media Matters, Princeton University climate scientist and IPCC lead author Michael Oppenheimer stated that “if [he] were the press,” he would state that rainstorms in the Midwest are increasing in frequency, the “models suggest this trend will continue,” and “heavy precipitation, all other things being equal, will generally lead to more flooding.” Oppenheimer concluded that it would be “not only appropriate, but advisable for the press to include such statements.” Oppenheimer cautioned that “it's almost impossible in most situations to connect climate change in a cause and effect way to a particular episode,” although some heat waves and other events have been attributed to climate change through modeling. He added that human management practices such as damming have a great influence over whether heavy precipitation leads to flooding. [Phone conversation, 5/1/13]
Trenberth: “Insights As To Why The Flooding Occurs” Are “Welcome.” Kevin Trenberth, a Distinguished Senior Scientist in the Climate Analysis Section at the National Center for Atmospheric Research, wrote in an email to Media Matters:
Yes I think any insights as to why the flooding occurs is always welcome. Of course it is easy to say it is “weather”, but the weather occurs in a changed environment: one that has more moisture in the atmosphere overall by about 4 to 5% compared with 30 to 40 years ago, and associated with global warming. More moisture means more rain where and when it does rain: and so greater risk of floods. This affects decisions on what to do subsequently: whether to redo whatever damage was done or redo differently to take account of changing risk? Maybe not build in the flood plain? Etc.
In a subsequent email, Trenberth wrote that there is a trend of the media ignoring climate change even when events that have been made more likely by climate change occur, which is “disappointing and even irresponsible”:
What I would add is that coverage of this sort has been dwindling. Last year with all the wild fires and exceptional heat there were very few media reports that mentioned the drought and connections to climate change. The coverage was disappointing and even irresponsible. [Email exchanges, 4/30/13]
Fasullo: It's “Certainly Appropriate To Frame” Midwest Floods In The Context Of Climate Change. John Fasullo, a climate scientist at the National Center for Atmospheric Research, wrote in an email to Media Matters:
I think it's reasonable to frame the event in the broader context of recent extremes, especially extreme drought transitioning to flooding from 2010 to 2012 across large portions of the US. In fact, we currently see simultaneous wide-spread flooding and drought conditions in the central of the country (http://droughtmonitor.unl.edu).
Of course the question people are going to reflexively pose is “Is it caused by climate change?” But I think it is much more appropriate to ask whether climate change has influenced these types of events. Clearly the odd behavior we are witnessing, both at the moment and over the past several years, is consistent with the modulating influence of climate change. Quantifying exactly how much of an influence is a complicated task, one that is likely to have considerable uncertainty given the state of current models. I'd await some well-designed targeted studies to address that question (to date I have not seen one) but it is certainly appropriate to frame the topic in the context of climate change's broader influence. [Email exchange, 4/30/13]
Kunkel: Not Understanding How Climate Change Is Impacting Floods May Lead To A “False Sense Of Security” About Infrastructure. When asked whether the press should include statements such as “heavy rainstorms in the Midwest are increasing in frequency and climate change models suggest this trend will continue,” Ken Kunkel, a scientist at NOAA's National Climatic Data center who specializes in extreme events, responded “A statement like the one you quote is a reasonable one and does not overstate the scientific understanding about historical trends and possible future changes.” He added that we need to understand how climate change is impacting floods so that we do not have a “false sense of security about the adequacy of infrastructure currently being planned and built”:
When infrastructure that needs to be resilient to runoff from heavy rain is planned, the design engineers are typically required to use design values for heavy rain, for example, the 100-yr storm. Such design values have been determined by the National Weather Service and are available in a series of publications. However, these design values are based entirely on historical storms and do not incorporate possible future changes due to anthropogenic climate change. One reason this has not been done is that there is no generally-accepted methodology for inclusion of possible future anthropogenically-forced changes. In my own personal research, I am exploring this issue and I personally think we need to provide decision-makers with some guidelines. Otherwise, we may have a false sense of security about the adequacy of infrastructure currently being planned and built. But, there is much research and development that needs to be done to develop guidelines. [Email exchange, 5/3/13]
Meehl: Climate Change Has Increased The “Odds For Flooding” In Midwest. Jerry Meehl, a senior scientist at the National Center for Atmospheric Research and a lead IPCC author, told Media Matters that “it's hard to attribute a particular event to a particular cause, and the way I always try to present it is you've shifted the odds for these precipitation and flooding events.” He added that it's become “difficult to have any kind of rational discussion” of climate change, which is “discouraging to me because climate change is a science issue not a political issue” and “if I would have one thing to say, it would be let's talk about this as a science issue, climate change is a science issue that affects everyone.”
In an earlier email to Media Matters, he explained that “higher levels of greenhouse gases increase the odds for flooding events such as the ones we're seeing now in the upper midwest”:
Observations have shown that the northern tier of states has been getting wetter, and the southern tier drier. This is consistent with climate model simulations of the effects of increasing greenhouse gases (basically the wet areas get wetter, the dry get dryer). Observations also show that precipitation intensity has been increasing, and models show this as a signature of increasing temperatures (warmer air holds more moisture, so for a given precipitation event, more rain or snow falls--when it rains it pours). These atmospheric responses to higher levels of greenhouse gases increase the odds for flooding events such as the ones we're seeing now in the upper midwest. [Email exchange, 5/1/13]
Budikova: “I'm Not Sure” Why Media Are Not Tying In Climate Context Of Floods. Dagmar Budikova, a scientist at Illinois State University who has published research about climate change and Midwestern flooding, stated in a phone conversation that “you can tie it in, but you have to do it very carefully.” She said that journalists “could be doing that and I'm not sure why they wouldn't be.” She added they may simply be “trying to be very careful” as “reporting on climate change is not a simple task” and it is “dangerous” to “assume that anything anomalous is related to climate change.” However, she stated, in the case of Midwestern flooding, “the literature is definitely converging to this idea” that flooding is increasing, and “more and more evidence is mounting to suggest that it may have to do with anthropogenic climate change.” When asked whether it was important for the media to mention the climate context of the floods to make the public more aware, she said “I would think that probably the more aware people are about anything really, the better we are off” and that it is most likely that “the media would be the vehicle” to bring it to the public's attention. [E-mail, 5/1/13] [Phone conversation, 5/6/13]
Hirsch: It's A “Reasonable Hypothesis” But “Evidence Is Unclear” On Whether Precipitation Will Continue To Increase. Robert Hirsch, a research hydrologist at the U.S. Geological Survey, wrote in an email to Media Matters that while it's a “reasonable hypothesis that anthropogenic climate change could change flooding risks,” the increase in precipitation may not continue. In a phone conversation, Hirsch added that while climate models have projected further precipitation of the region, “there's been very little testing,” which is done through hindcasting, of whether these models are skillful. From his email:
I think it is a reasonable hypothesis that anthropogenic climate change could change flooding risks. However, the evidence to date is very unclear about this, and we know that the climate models, while they may be able to project changes in temperature fairly well do not do well at all when it comes to the kind of heavy precipitation events that produce floods. What we know when we look at the last 140 years or so in the midwest, that there have been some pretty large swings in the size of floods, and much of that is probably not related to anthropogenic climate change. There were very large floods in the last half of the 19th century, much smaller floods generally in the first half of the 20th century, and now we seem to be in another period of larger floods. We don't think this can be explained by greenhouse forcing, but may be a normal periodic oscillation in the climate.
I would say that human activities on the landscape may be as big a factor or bigger than climate change when it comes to changing the size of floods in this region. Urbanization and land drainage can be significant contributors to increased flooding. [Email exchange, 4/30/13] [Phone conversation, 5/1/13]
We searched Nexis and Factiva databases for articles and segments on “flood!” between April 1 and May 3, 2013. Our results include four major television outlets (ABC, CBS, NBC, CNN), seven national print outlets (Associated Press, Reuters, Los Angeles Times, USA TODAY, New York Times, Washington Post, and Wall Street Journal), and eight local newspapers (St. Louis Post-Dispatch, Kansas City Star, Chicago Tribune, Chicago Sun-Times, Des Moines Register, Detroit Free Press, Minneapolis Star-Tribune and Indianapolis Star).