Photo: Elizabeth Thomsen via Flickr. Increasingly, consumers are trying to reduce the environmental impacts of the foods they eat. But it's not so easy to know what to do, in part because of the bewildering array of food choices the market offers, but also because it's hard to know what food choices carry the biggest impact. This nifty study tries to clear away some of the murk by tackling a fairly straightforward question: If you care about the climate, which is more important, what kind of food you eat, or where that food is grown? To summarize the findings: All …

Photo: StuSeeger via Flickr. My pal Peter Dorman is looking for answers: Does the class of economic forecasting tools known as "computable general equilibrium models" (aka CGE models) have any documented track record of success? This may seem like an arcane point, but it's quite relevant to climate policy. Government agencies throughout North America are using CGE models to forecast the economic impacts of various cap-and-trade proposals. But many academic economists -- Dorman among them -- think that the CGE models are built on sand. Says Dorman: I think these models are so dubious theoretically and unreliable in practice that …

Photo: sean-b via Flickr University of British Columbia researchers have put a price tag on happiness. The good news: It's available for the low price of $5. The better news: You can't spend that money on yourself. Instead, to get the most smiles per dollar, you have to spend money on other people. Dr. Elizabeth Dunn at the University of British Columbia, Vancouver and colleagues found that [experimental subjects] report significantly greater happiness if they spend money "pro-socially" -- that is on gifts for others or on charitable donations -- rather than spending on themselves. The researchers apparently looked at …

Last week, my colleague Eric de Place dinged the Western Climate Initiative -- an effort by Western states and provinces to develop a carbon market with a strict, declining cap -- for kicking the can down the road on transportation fuels. Of course, the WCI has not ruled out the possibility of capping emissions from the transportation sector. They've just delayed a decision until they run some more economic analysis. So there's no reason to gnash our teeth over a lost opportunity -- not yet, anyway. Still, it's hard to tell whether the glass is half full (transportation fuels haven't …

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! A few years back I wasted hour after hour playing with the java settings, and watching "traffic" jams materialize and melt -- just like in real life. My favorite quirk: for one lane-narrowing scenario, I could make traffic flow along beautifully at 40 miles per hour, but seize up like glue at either 20 …

I thought this was clever -- a Cliff Notes version of climate-friendly lifestyle choices. Click the image for the full-sized version. There's nothing groundbreaking here, really, but it's a nice summary. And it's cute!

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 …

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 ... The yellow arrow represents the passage of time, the horizontal axis represents fuel …

By now, I think most people understand that organic food is supposed to be healthier for you. But I think there are still some people who feel that the health benefits are a just a bunch of marketing hype. Well, this new study suggests that it ain't just hype -- organic produce really does reduce kids' exposure to some potentially risky pesticides. From the Seattle P-I: The peer-reviewed study found that the urine and saliva of children eating a variety of conventional foods from area groceries contained biological markers of organophosphates, the family of pesticides spawned by the creation of …

Here's a clear demonstration of why, in a cap-and-trade system, grandfathering emissions rights to historic polluters is a terrible idea: The UK's biggest polluters will reap a windfall of at least £6bn from rising power prices and the soaring value of carbon under the new European carbon trading scheme ... Critics argue ... that the scheme, under which nearly all allowances are granted free of charge rather than having to be bought by big polluters, has created a distorted market in which the worst offenders will enjoy bumper profits while incurring no extra underlying cost for producing greenhouse gases. That's …