The science continues to point to the cold, hard fact that global warming is happening and will get worse, but the number of people who believe this scientific certainty has declined over the past year, leaving environmentalists and climate scientists scratching their heads in disbelief.

The reason for all of this uncertainty, argues James Hoggan, author of Climate Cover-Up: The Crusade to Deny Global Warming (Greystone Books, $15), is a concerted effort by public relations professionals to undermine climate change science and create uncertainty among the public — all to please clients who would be negatively affected by meaningful carbon legislation to curb emissions.

So how does Hoggan know all this? As a public relations professional himself, he has seen it with his own eyes.

As president of a successful public relations firm and co-author of the, which reports on PR pollution that clouds climate science, Hoggan works with Richard Littlemore to ruthlessly report on his industry’s ingenious tactics to hijack the global warming debate — all with the compliance of media and leaders in government and business.

To give readers a clear idea of how badly some PR firms and their clients have muddied the global warming debate, Hoggan goes back to 1988, when the great scientific bodies and even politicians were both convinced that humans were causing climate change and concerned enough to do something about it.

Three decades later and people are still debating the science. Meanwhile, the Earth continues to warm.

So what happened? According to Hoggan, public relations firms have been hard at work, using a number of schemes to insure that climate change remains a debate.

For example, over the years there has been an explosion in the number of think tanks and organizations like The Heritage Foundation, Friends of Science and Americans for Balanced Energy Choices, which all have the common goal of countering any progress toward changing the way we create and consume energy.

Another common tactic used by public relations firms is to recruit and promote so-called “experts” who will debate scientific facts published in peer-reviewed journals. Upon further scrutiny, these experts usually lack scientific credentials or they are funded by groups that raise questions about their impartiality.

But by far one of the most frustrating tactics used by PR firms is to systematically dissect all reputable conclusions on climate change to emphasize that there is not 100 percent certainty that global warming is occurring; therefore, we shouldn’t do anything about it.

However, as Hoggan brilliantly points out, this logic is inherently faulty when applied to other situations. 

For example, “If scientists told you there was a 90 percent likelihood that your plane would crash, you would assuredly forgo the trip,” he writes.

It is this kind of common sense logic combined with in-depth, investigative reporting that makes Climate Cover-Up well worth the read. After all, if people are made aware of the tactics being used to keep the climate issue a “debate,” hopefully that information will help arm them against future dishonest claims about climate change.