As millions of people on the US east coast remain without power in the wake of hurricane Sandy, the media are still speculating over how far the storm can be linked to climate change. With a complicated range of factors affecting hurricane activity, we asked climate scientists how satisfied they are that the media got it right this time?
Hurricane Sandy tore through the Caribbean and the US east coast last week, killing 160 people and causing $20 billion worth of damage. As the Guardian points out, Sandy has forced climate change further up the political and media agenda. Emilee Pierce from US media fact-checking website, Media Matters, told us:
“In the days leading up to landfall in the U.S…very few in the press mentioned the words ‘climate change.’ But once it hit New York and DC…the connections started coming — from journalists and politicians alike.”
Using satellite data gathered since the 1970s, scientists have found an increase in the intensity of tropical cyclones, associated with a human-induced increase in sea surface temperature. But attributing specific storms to climate change is tricky.
Most news outlets carried the measured message from scientists that while some specific extreme events, such as heat waves, can be attributed to climate change, this is far more difficult for hurricanes. With this in mind, most scientists we spoke to seemed broadly pleased with media outlets’ coverage.
Kathy Maskell, communications manager with the Walker Institute for Climate System Research at the University of Reading called the majority of media coverage “accurate, informative and objective”. Dr Jeff Masters, who runs the online weather service Weather Underground, agrees, citing one article in the Boston Globe as one good example. On attribution, the Boston Globe said:
“While Hurricane Sandy was not directly attributable to global warming, scientists say it fits a pattern of more severe weather influenced by climate change”.
But some outlets couldn’t help upping the ante. NBC Nightly News anchor Robert Bazell stated that events like Sandy should be considered the “new normal”. In response, Roger Pielke Jr, professor of environmental studies at the University of Colorado wrote in the Wall Street Journal that there are “no signs” that humans can yet be blamed for recent disasters like Hurricane Sandy.
Other scientists took a different view. Professor Kevin Trenberth, head of the Climate Analysis Section at the US National Center for Atmospheric Research, told Carbon Brief that the NBC piece was an example of good reporting, describing Pielke Jr’s comments as “not helpful”.
Even some measured stories couldn’t escape a bit of spin. Trenberth also pointed to Bloomberg Businessweek’s cover story, ‘It’s global warming, stupid’, as an example of good scientific coverage. But although the story appears balanced and informative from a science perspective, BusinessWeek editor Josh Tyrangiel reportedly tweeted:
“Our cover story this week may generate controversy, but only among the stupid.”
Bloomberg BusinessWeek’s take on the famous catchphrase from Bill Clinton’s 1992 presidential campaign.
An opinion expressed by meteorologist Dan Satterfield in his blog is that the media should concentrate less on attribution and more on the way climate change could exacerbate storm size and flooding.
Research suggests that warmer water in the tropics provides storms with more energy, making storms bigger and more damaging. What’s more, when storms pass over water they create a surge in sea level. Together with human-induced sea level rise, this can cause widespread flooding in vulnerable coastal areas.
According to the IPCC, the atmosphere is about 0.75 degrees warmer than it was at the start of the century and can hold 5-6 per cent more moisture. This means that there is more water available to fall as rain.
Satterfield also explains how a weather system over Greenland, possibly linked to Arctic ice melt, may have blocked Sandy’s path, forcing it into heavily-populated coastal areas rather than into the remote Atlantic Ocean.
More to come?
Professor Tom Knutson, meteorology expert with the US Geophysical Fluid Dynamics Laboratory, pointed to the New York Times as a good analysis of the nuances between linking hurricane activity and climate change. The article explains the scientific uncertainty surrounding what the past record of hurricane activity can tell us about the next few decades.
Most models suggest that as sea surface temperatures continue to rise, the number of severe storms will increase. But many other environmental factors also influence the generation and tracks of storms, including wind speed and direction in the atmosphere. So pinning down the long term trend will require a longer data record than we have now.
On how best to report the role of climate change, Knutson continues:
“A trap reporters can fall into is chasing after answers to a poorly worded strawman question: Did climate change cause this event? Instead the science will generally only be able to look at questions of attribution in a probabilistic sense: Has climate change altered the odds of events like this one occurring? How?”
So it seems that a few examples aside, scientists have been fairly satisfied with reporters’ representation of the science behind hurricanes and climate change – both what we know and what we don’t know. With Hurricane Sandy gone but far from forgotten, scientists seem hopeful that reporters can continue to ask the right questions about climate science.