“Knee-high by the Fourth of July” is the old saw about the height of corn in the rural irrigated parts of Colorado where it’s grown. But this year, hurried on by the hot weather, the stalks stood waist-high to my 6-foot-2 frame by the summer solstice –– nearly two weeks before the Fourth arrived.
We have had many such episodes of fecundity this year. Peaches are two weeks early. Dragonflies have swarmed in my suburban neighborhood, and, of course, we’ve had these huge wildfires.
Do we credit and/or blame global warming? And, more specifically, is that warming caused by humans? The conventional answer of climate scientists is that we’re still too close to see anything clearly; we can discern climate change only in the rearview mirror.
That rearview mirror clearly shows that the climate is warming, and it is consistent with models assembled to predict the effects of greenhouse gases accumulating in the atmosphere. Daily record high temperatures occurred twice as often as record lows from 1999 to 2009 across the continental United States, according to a 2009 analysis led by Gerald Meehl, of the National Center for Atmospheric Research in Boulder.
But weather extremes -- droughts and deluges, heat waves and hurricanes -- are trickier. The abnormal events are harder to pick out from what climate scientists call the background noise of historic variability.
Some scientists, most prominently Kevin Trenberth of the National Center for Atmospheric Research in Boulder, argue that extreme weather events have moved beyond the range of historic variability. For him, we have already amassed enough rearview perspectives to draw conclusions; now, he wants other climate scientists to stride more briskly up to the lectern and admit that the statistical evidence has become compelling. We are, he says, already in a new, human-altered normal, the human-influenced geological epoch that many scientists call the anthropocene.
Do journalists also have a responsibility to connect the dots of today’s weather with broad climatic shifts? And should we further link today’s weather with the accumulating greenhouse gas emissions that most scientists say are heating the globe?
A watchdog group called Media Matters recently examined the question within the context of how wildfires in the West are being reported. The group found that CNN, the Wall Street Journal and other national news outlets rarely mentioned climate change.
Media Matters then asked nine wildfire experts whether the media should include climate change in reporting on forest fires. Almost all said yes.
“Absolutely, journalists who care to look at the bigger picture should be stating that we already are seeing an acceleration of Western wildfire activity in the last 30 (years), and some of that acceleration is tied to the trend of earlier snowmelt and hotter, drier summers,” responded Steven W. Running, director of the Numerical Terradynamic Simulation Group at the University of Montana. “If the media do not connect these dots, the public probably assumes these latest events are only natural variability and ‘bad luck,’ when in reality they are a glimpse into a more common future if carbon emissions continue to rise.”
Two of the nine experts dissented. “Even the big fires currently blazing away are within the range of historic climates,” said Steven J. Pyne, of Arizona State University. “My personal evaluation of the situation is that we do not currently know enough to make reliable predictions about how global warming will impact future fires,” added Jon E. Keeley of the U.S. Geological Survey’s Western Ecological Research Center.
None of the experts denied the existence of climate change, nor their belief of human complicity in it. Rather, the disagreement was about how much certainty we have about human causes when we talk about this heat wave, that drought, or those wildfires.
That’s the problem with the story of global warming. We want specificity in black-and-white, not nuance. It’s like being in 1939, with war clouds gathering, but Pearl Harbor still ahead.
Computer climate models are predicting much of what is occurring: warming temperatures, ebbing sea ice in the Arctic, rising sea levels. That’s worrisome. But here in the Interior West, we have a very thin record of what constitutes normal, both in terms of temperatures and precipitation. Consider the 30-year megadroughts of 900 years ago that may have caused the Ancestral Pueblo people to abandon their cliff dwellings at Mesa Verde. That was long before humans started burning fossil fuels. Yet an entire civilization collapsed, and its people dispersed.
Humans crave the simple stories of winners and losers, saints and sinners. Too, we live in the moment of yesterday’s box scores and tonight’s big game. Climate challenge, with all of its uncertainties, great risks and the need to look far into the future, is a difficult story to tell. The nuances are difficult to distill into two sentences that get inserted into a story about today’s weather or this summer’s corn crop. Yet try we must.