As bookshelves increasingly sag with climate change books, it would be hard to find one more useful to journalists than Robert Henson’s The Rough Guide to Climate Change, recently issued in a second, revised edition.

The book, first published in 2006, is an engaging and comprehensive primer that veteran environmental or science reporters and global warming neophytes alike could benefit from reading – or simply having nearby as a ready reference.

A reviewer for USA Today called it “the best book on climate change I’ve read.” The Royal Society – the U.K.’s national academy of sciences – honored The Rough Guide to Climate Change by short-listing it for the Royal Society Prizes for Science Books in 2007.

In the book, Henson interestingly explains a range of material, starting with the basics of global warming, then moving to discussions of the state of climate science, debates and solutions, and what the reader can do to help address the issue.

The text’s casual, journalistic style shouldn’t be surprising, considering the author’s background. As an undergraduate, he pursued an interdisciplinary major in meteorology and psychology. Graduate studies in both meteorology and journalism followed, leading to an M.A. thesis in journalism that examined local television’s treatment of severe weather warnings.

Since 1989, Henson has worked on the communications staff of the University Corporation for Atmospheric Research, UCAR – the Boulder, Colo., institution that operates the National Center for Atmospheric Research. NCAR scientists’ work has strongly influenced the increasingly certain statements of the United Nations/World Meteorological Organization’s Intergovernmental Panel on Climate Change (IPCC) that Earth is warming, human actions are a main cause, and serious climatic consequences are likely.

Among other duties, Henson’s job involves editing the “UCAR Quarterly” and sometimes assisting reporters. The Rough Guide to Climate Change was an independent, freelance undertaking. To avoid any appearance of a conflict of interest, he said he tried to be “judicious” in his handling of NCAR. References to the organization are listed on only three pages in the book’s index.

His previous freelance books were Television Weathercasting: A History in 1990 and The Rough Guide to Weather in 2002. Best known in the United States for its travel guides, Britain’s Rough Guides series also includes reference books that range from scientific subjects to topics such as babies, reggae music, and Shakespeare.

Henson recently talked about The Rough Guide to Climate Change, climate journalism, and scientist-journalist communications with The Yale Forum.

Despite his preparedness for writing an in-depth book about climate change – training as a meteorologist, long experience writing about weather and climate, years of service at NCAR – he still felt the need for some intensive study. Among other things, he said, the effort involved reading an entire college-level textbook to get better acquainted with one topic.

The textbook was Earth’s Climate: Past and Future, which addresses paleoclimate – climate change through Earth’s history. The author, William F. Ruddiman of the University of Virginia, “was extremely gracious in answering questions and generally helping me get up to speed on paleoclimate issues,” Henson said.

Despite that expert help, paleoclimate was one of the subjects he found toughest to explain well in the book, he said. The other was computer modeling to simulate climate change.

It’s not that modeling is so hard a subject to grasp, he said, but much of the technical jargon – even the phrase “computer modeling” itself – is unknown to many people. To tackle that problem, Henson likened climate modeling to an artifact of contemporary culture that is undoubtedly far more familiar to most readers:

“The best analogy to a climate model may be a state-of-the-art computer game,” he wrote. “Instead of cars tearing down a racecourse, or warlords fighting over territory, this game follows the heating, cooling, moistening, and drying of the atmosphere. It’s not quite as sexy but far more important to the future of the planet.”

Henson said he also found it tricky to write about the charged subject matter in a chapter titled “A heated debate: How activists, skeptics and industry have battled for column inches and the public mind.”

The difficulty, he said, arose largely because he was writing a book simultaneously targeting the British and American markets at a time, in 2005, when public discussion of the climate issue was very different in the two countries.

Many Britons, for instance, had typically left behind the questions Henson felt were still dominant in the U.S. at that time – is global warming happening or not, and if it is, are humans or nature the cause?

“I was trying to write the book so it was not namby-pamby to the British, but was not too far gone to the Americans,” he said. “I was not preaching to the choir or to the skeptics.”

The “different mindsets” that Henson perceived as prevalent in the two countries, along with the climate issue’s greater prominence in Britain, can be seen in the strikingly different responses that The Rough Guide to Climate Change received when the publisher sent copies and a three-question survey to all elected Members of Parliament in November 2006 and then to every member of the Senate in February 2007.

Nearly half of the MPs in the House of Commons – 318 representatives in that body – responded to the questions seeking their views on the importance of the climate issue and what Britain and individual British citizens can do about it.

According to the Rough Guides website, the opinions expressed were “almost unanimous” from members of all parties, with this statement by Conservative Richard Benyon typical: “Climate Change is the defining issue of our age. Previous generations had to deal with the rise of Nazism or communism. This is the issue on which my generation of politicians will be judged. This is our Dunkirk.”

Only three of 100 American senators responded at all, and none of them answered the survey questions.

Still, Henson believes there have been big changes in both the public discussion and media attention to climate change in the U.S. since he wrote the first edition of the book in 2005.

“There’s a lot less dueling-scientist coverage, which is great,” he said. “There’s been a huge improvement in the U.S. coverage over the last three years. Looking at the coverage in England, they were already about where we are now, and it’s nice to see we’ve gotten there.”

Henson expects greater media attention to technological and political aspects of climate change in the next few years and doesn’t foresee “huge changes” in the basic findings produced by climate scientists.

Still, he cited a science-related problem as one of the biggest challenges facing journalists covering climate change in the years ahead – how to report on the incremental nature of scientific research and discovery.

“It takes a long time to get the big picture,” he said. “No study is the final word in this area. Even the IPCC is not the last word.”

New scientific findings did not account for most of the changes in his book’s second edition. The IPCC set a cutoff date in 2005 for studies to be included in its major update reports in 2007 summarizing the state of climate science.

Henson, working on the book’s first edition through mid-2006, was therefore able to refer to very recent scientific findings that were clearly “leading to” the IPCC’s conclusions. This, he said, made it much easier to update the book for its 2008 second edition – in many cases, simply by incorporating the IPCC’s own statements.

The book ended up growing from 341 to 374 pages from the first to second editions. Much of the new material was added to the “What you can do” section, he said, such as a page-long discussion entitled “Weaning yourself from bottled water” in the “Shopping” chapter. (Regarding bottled water, he wrote that “it would be hard to imagine a more gratuitously wasteful product.”)

Just as he believes journalists will increasingly be grappling with the political and economic dimensions of climate change, Henson also thinks scientists communicating with journalists on the subject will face related challenges.

“One is for scientists to be able to separate themselves as scientific creatures and citizens of Planet Earth,” he said.

Scientists tend to say what they know, while journalists often ask them what should be done to address climate change, he said. Some scientists will demur, saying that is not their field, while others will respond with strong opinions about what they think are necessary actions.

“I can see both sides as to how far scientists should go in connecting the dots of what science says and where policy should go,” Henson said.

One possible approach, he said, “is for scientists to say ‘if we don’t do this, then this will happen.’ They’re not recommending, they’re just saying we can expect that to happen. This is not policy-prescriptive, but policy-savvy.”

In any event, he added, it will be good for scientists to remember – as discussions evolve about what comes after the Kyoto Protocol and what the U.S. should do about climate change – that journalists and others will want to know what scientists think about those issues.