Articles by Clark Williams-Derry

A fun traffic simulator and lessons learned

Via Brad Plumer: a traffic jam in in a bottle.

To me, it's pretty remarkable how closely the real-world experiment above matches up with this java-based computer traffic simulator.

Warning: if you click the last link, and you're at all geeky, prepare to lose your afternoon!

Cuteness saves the climate

I thought this was clever -- a Cliff Notes version of climate-friendly lifestyle choices. Click the image for the full-sized version.

Can we trust carbon labeling?

About a year ago, I was cautiously bullish on British supermarket giant Tesco's pledge to start putting carbon labels on its food. But I think that their progress so far -- which I'll get to in a minute -- suggests an important lesson about the policy risks of treating a fuzzy exercise as if it were completely reliable.

Tesco's idea was that the chain and its suppliers would pay for objective, comprehensive reviews of the greenhouse-gas emissions from the foods on the store's shelves. The analyses would cover all major steps in bringing food from farms to the checkout line -- everything from running farm machinery, to food processing, to transportation, to refrigeration. Then, each item in the store would be labeled with the climate-warming emissions that could be traced to that particular product.

This sort of exercise is called "life cycle analysis," and it's been used for decades to great effect, to shed light on all sorts of questions: paper vs. plastic (for bags), cloth vs. disposable (for diapers), hybrids vs. hydrogen (for cars), and a host of others.

Last week, a nifty article by Michael Specter in The New Yorker reported on Tesco's progress so far. The results? There's still only one product on the shelves with a carbon label -- a single brand of potato chips, or "crisps" in British parlance.

You see, as it turns out, life cycle analysis can be really, really difficult. And to make matters worse, it may be that the whole enterprise is chock full of uncertainty.

Where carbon is concerned, it can be hard to trust the label.

A timeline of changes in automotive fuel economy

This should be perfectly obvious, but automotive technologies have changed an awful lot over the last few decades. From about 1975 through 1987, federal standards prompted massive and surprisingly rapid improvements in fuel economy. Cars designers focused on nimbleness and efficiency over raw power, and the fuel savings were enormous.

But since the late 1980s, most engineering advances have focused on making cars more muscular, and fuel efficiency has taken a back seat.

For graphic proof, take a look after the jump at a nifty chart ...