Hot? Yes, and dry, too. But can you blame it on global warming?
This article was written in June 2012 during Colorado’s blistering heat wave after a winter parched of snow and a rash of fires. It was distributed by Writers on the Range.
by Allen Best
Knee-high by the Fourth of July is the saw in Colorado’s corn-growing country. This year, hurried by the hot weather of spring, the stalks stood waist-high against my 6-foot-2 frame in a field that I visited between Mead and Loveland on June 23, the first day of summer.
We have had many outliers of this fecundity: early peaches, corn and cantaloupe, plus cicadas in June instead of August. This year we also had six months of above-average heat, if nothing approaching the all-time record of 114 degrees set in the 1930s and 1950s, two other times of heat and drought. We also had those huge, horrible forest fires.
Is global warming to blame? And more specifically, is it human-caused warming?
The conventional answer of climate scientists is that is that climate change can only be discerned clearly in the rear-view mirror. The scientific record is clear: the planet is warming. and the changes are 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 an analysis led by Dr. 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 noise of historic variability.
Some scientists, most prominently Dr. Kevin Trenberth, of the National Center for Atmospheric Research, argue that extreme weather events have moved beyond the range of historic variability. For him, we have enough rear-view perspective to draw conclusions. He wants other climate scientists to stride more briskly to the lectern to admit that we already live in a new, human-altered normal, what some 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 nearly all scientists agree are heating the globe?
A watchdog group called Media Matters this summer found that CNN, the Wall Street Journal and other national news media change rarely mentioned climate change in their coverage of wildfires. The group asked nine wildfire experts whether they should have. Most 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 Dr. 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 on the panel dissented. “Even the big fires currently blazing away are within the range of historic climates,” said Dr. 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,” said Dr. 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 of human complicity. Rather, the minority disagree about the relative certainty of human causes in this heat wave, that drought, or those wildfires.
The broad brushes are clear enough: Computer climate models have predicted much of what is occurring: warming temperatures, ebbing sea ice in the Arctic, rising sea levels.
In the West, we have a very thin record of what constitutes normal, both in terms of temperatures and precipitation. Some 900 years ago, megadroughts that lasted decades may have caused the Ancestral Pueblo to abandon their cliff dwellings at Mesa Verde. What were bark beetle infestations like during those droughts? Wildfires? We don’t know. Our understanding of “normal” is limited.
That’s the problem with this story of global warming. We crave simple lines of cause and effect, black and white, winners and losers. This story has nuance. It’s difficult to distill these uncertainties of giant risk in the distant future in a story about today’s weather or this summer’s corn crop.
But even if we can’t pin the tail of global warming on every weather extreme, we must continue talking about the looming risk. It’s too bad there’s barely been a whisper at the national political conventions.