Unless you’ve been living under a rock — if so, way to live simply! — you’ve probably heard a smidgen about the summary of a hefty climate report released to the public today by the Intergovernmental Panel on Climate Change. In fact, you’ve probably heard the acronym “IPCC” bandied about with some regularity in the past few years. But what exactly is this panel, and why should you care about some report it threw together?

Take a closer look.

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Glad you asked. Way back in the olden days of the 1980s, even before the dirty hippies got all worked up about it, a growing number of scientists were raising warning flags about anthropogenic climate change. In 1988, two U.N. agencies — the World Meteorological Organization and the U.N. Environment Program — established the Intergovernmental Panel on Climate Change to gather information on the subject. All countries that are members of the WMO or UNEP can join the panel, and 192 countries have. IPCC data-gathering involves, in one way or another, some 2,500 scientists, including many of the world’s top climate experts. The process through which its reports are generated is exhaustive — if you wish to be exhausted, see the Procedures for the Preparation, Review, Acceptance, Adoption, Approval, and Publication of IPCC Reports [PDF]. Drink several cups of coffee first.

But, uh, what does the IPCC do? The IPCC doesn’t conduct research or run experiments. Instead, it gathers, sifts, and summarizes the best information available. IPCC reports are intended to be “comprehensive, objective, open, and transparent” assessments of the state of scientific knowledge on climate change. The bulk of the info comes from scientific and technical data published in peer-reviewed literature. (Note: Only studies published in peer-reviewed journals pass muster in the scientific arena. Let no climate skeptic tell you otherwise.) Three working groups within the panel consider different aspects of climate change: Working Group I assesses the relevant science; Working Group II considers the potential positive and negative consequences of climate change on the natural world and the economy, and ways the world can adapt to them; and Working Group III works on options for slowing or halting climate change.

What’s the point? The IPCC doesn’t gather scads of data just for kicks. It issues comprehensive reports at “regular intervals.” The first Assessment Report hit the scene in 1990. The second came in 1995, and was instrumental in the negotiations that led to the adoption of the Kyoto Protocol in 1997. The Third Assessment Report (TAR) was completed in 2001, and — you guessed it — 2007 is The Year of the Fourth Assessment Report.

FAR out! Indeed. And if you think that’s exciting, there’s more to come — today’s highly scrutinized report is only the Working Group I song and dance. Working Group II will issue its adaptation-focused contribution to the Fourth Assessment Report in April; Working Group III will publish its mitigation-y findings in May; and a Synthesis Report wrapping together the key findings of all three groups will be published in late 2007.

Repeat after us. So why is today’s report such a big deal? Because the IPCC is the gold standard. The Big Kahuna. The top of the line. The Apple iPhone. Seriously: it is one of the most ambitious, comprehensive, heavily reviewed, authoritative knowledge-gathering enterprises ever undertaken. It’s got its flaws — it’s been called, not without justification, slow, bureaucratic, and politicized — but it is nonetheless as close as humanity is ever likely to get to the Final Word on climate change.

The Inhofes of the world will stomp their feet, cover their ears, and chant “La la la, I can’t heeear you.” But rest assured, if anybody’s got their finger on the rapidly warming pulse of the globe, it’s the IPCC. So read ’em, weep if you must — and consider yourself all the more prepared to kick some climate-change ass.