Clothing sucks. I mean, it's fine for keeping people from walking around naked all day, but finding the right mix of stuff to wear to keep you at the absolute perfect temperature is always tricky. A clothing company called Klymit has a better idea: a jacket with adjustable warmth using pockets of argon gas.
Insulation is a very simple concept: in general, or at least, when it comes to clothing, you want to have the most amount of volume with the least amount of actual stuff in between you and whatever you want to be insulated from. This is why aerogel does such a good job as insulation: it's 96% nothing at all. While most of us don't have aerogel in our jackets, down (synthetic or otherwise) serves the same purpose: a lot of poofiness to keep the cold away, without having a lot of material to transmit cold in and heat out.
Instead of poofy material (or any other actual stuff of any kind), Klymit has started using inflatable pockets of intert gas (argon, in this case) in their jackets instead. Without any inflation, the jacket is essentially just a windbreaker, but using special cartridges, you can poof it up to create the equivalent of 14 millimeters of insulation without adding any weight at all. And if you get too hot, just let some of the gas out, and the jacket cools off. It's compact, it's simple, and it's effective.
Now, while argon is all well and good (and we definitely appreciate that it's the most piratey of all the elements), how about using another inert gas like helium instead? That way, the more insulation you need, the lighter your jacket gets, until eventually it'll just pick you up into the air and float you to a warmer latitude.
Look for Klymit's Ulaar jacket to launch in the United States this fall.