One thing I find most difficult to convey to people is the scale of the energy enterprise. Energy is the largest economic activity on earth (much larger than agriculture) and the industry with the highest capitalization (much higher than car manufacturing). Energy units are confusing (megawatts, kilowatt-hours, tons of carbon, CO2 equivalents, BTUs and Gigajoules), but the scale of the system makes these units even more remote (terawatt-hours, exajoules, gigatons, quadrillion BTUs). This makes it hard to bring the discussion home -- the discussion starts in a rarified, almost other-worldly place. (Click chart below for larger view.)

Let's talk gigatons -- one billion tons. Every year, human activity emits about 35 gigatons of CO2 (the most important greenhouse gas). Of that, 85% comes from fossil fuel burning. To a lot of people, that doesn't mean much -- who goes to the store and buys a gigaton of carrots? For a sense of perspective, a gigaton is about twice the mass of all people on earth, so 35 gigatons is about 70 times the weight of humanity. Every year, humans put that in the atmosphere, and 85% of that is power. Large actions, across whole nations and whole economies, are required to move the needle.

This takes us to the next issue in talking about energy - our current system works pretty well. In the U.S., most power companies keep the lights on 99.99% of the time or better. Usually, there's gas at the corner station. There's a reason we burn stuff -- it's hard to beat! The world uses more coal than it did 10 years ago. It uses more wood than it did, more everything.

To cut emissions, urgent and critically important, we need new energy supplies (biofuels, solar, wind, advanced nuclear, coal with sequestration) with much lower carbon footprints. But 100 watts is 100 watts however generated -- the swap to carbon free energy raises costs but produces only intangible benefits. We can't start the conversation by saying that everything will cost more, and the benefits are immense but you can't easily see them. It's hard enough to get people to take their medicine or lose weight when it directly improves their health - changing energy systems is a hard sell under any context. (Click for larger.)

Any action on the challenges we face -- and in the huge, dizzying, active enterprise there are plenty -- starts with a story: a story that's hard to tell easily and well. For this reason, decision makers in both industry and government have a unique need and responsibility to their stakeholders to understand how the climate and energy systems work. They have a unique need to understand the dimensions of the problem and a responsibility to be knowledgeable in the face of uncertain, difficult choices. They need to separate sense from non-sense, and invest in the present and the future with that limited knowledge. Because real solutions that aren't all "eat your peas" or "don't worry -- be happy", narrative is the strongest tool they require to affect enduring change.