We estimate that over 170 million Americans alive today were exposed to high-lead levels in early childhood, several million of whom were exposed to five-plus times the current reference level. Our estimates allow future work to plan for the health needs of these Americans and to inform estimation of the true contributions of lead exposure to population health. We estimate population-level effects on IQ loss and find that lead is responsible for the loss of 824,097,690 IQ points as of 2015.

Efforts to reduce carbon pollution using ethanol appear to have backfired. //

For over a decade, the US has blended ethanol with gasoline in an attempt to reduce the overall carbon pollution produced by fossil fuel-powered cars and trucks. But a new study says that the practice may not be achieving its goals. In fact, burning ethanol made from corn—the major source in the US—may be worse for the climate than just burning gasoline alone.

Corn drove demand for land and fertilizer far higher than previous assessments had estimated. Together, the additional land and fertilizer drove up ethanol’s carbon footprint to the point where the lifecycle greenhouse gas emissions—from seed to tank—were higher than that of gasoline. Some researchers predicted this might happen, but the new paper provides a comprehensive and retrospective look at the real-world results of the policy. //

Today, most gasoline sold in the US contains 10 percent ethanol, and about a third of the corn crop in the country is used to produce the fuel. While other sources would qualify, including ethanol derived from cellulose, “most RFS biofuel production has come from conventional corn ethanol,” the study’s authors pointed out. //

Expanding biofuels production would only add to the inflation, the researchers found. “Our estimates imply that for every billion gallons per year (BGY) expansion of ethanol demand, we would expect a 5.6% increase in corn prices; 1.6 and 0.4% increases in the areas of US corn and cropland, respectively; and attendant increases in GHG emissions, nutrient pollution, and soil erosion,” they wrote.

Would love a detailed breakdown from Ars on the impact of these launches on the climate and environment. Thank you!

Everday Astronaut has an excellent article on this: https://everydayastronaut.com/rocket-pollution/

Summary: some exotics suck, but modern rockets are inconsequential at current volumes.

The impact of rocket pollution is mostly symbolic, especially tourist flights. They're seen as the most conspicuous consumption by much of the general public. Why should an average Joe who is struggling to get by sacrifice to combat climate change while billionaires are dumping hundreds of tons of carbon into the air to fly to space?

There are already good answers to that question, but they are nuanced, and the answer could be quite clear. Bezos' rocket already runs on Hydrogen, he should be paying a little extra for green Hydrogen, just for PR reasons. Musk has already committed to using synthetic methane on Starship. Branson doesn't have an easy answer, but he's mostly irrelevant in the symbolism arena. //

Would love a detailed breakdown from Ars on the impact of these launches on the climate and environment. Thank you!

~16.25 billion gallons of jet fuel burned per year.

One Falcon 9 launch, 25,000 gallons of Kerosene in the 1st stage (the 2nd stage is effectively burning it above the atmosphere, so not sure you can count that).

30 launches in 2021. 750,000 gallons of kerosene.

Total around the world launches of Rockets in 2021 was, what? 60 ish? Many smaller rockets. Let's just double that though and say 1.5 million gallons.

That is ~3.33% of all of the jet fuel burned...in one day. For an entire YEAR of launches at the current rate.

Metholox will produce somewhat lower emissions per joule of energy released to launch a rocket.

So basically, you are talking less than 1/10th of 1% of the entire aviation industry. It would be nice if it was zero emissions. Also of note, SpaceX is looking to do carbon capture and generate methane for launch at some point (though not soon, they will be using in situ wells at their launch facility for the methane).

Until such a point as rocket launching maybe approaches >1% of aviation emissions I think we can safely consider it a rounding error.

edit actually the above should be less than 1/100th of 1%. //

Would love a detailed breakdown from Ars on the impact of these launches on the climate and environment. Thank you!

A very large percentage of the information about those hurricanes comes from satellites. So there’s a pretty big impact from rocket launches.

Reliance on coal-fired electricity to produce solar panels raises concerns in the West

Solar panel installations are surging in the U.S. and Europe as Western countries seek to cut their reliance on fossil fuels.

But the West faces a conundrum as it installs panels on small rooftops and in sprawling desert arrays: Most of them are produced with energy from carbon-dioxide-belching, coal-burning plants in China.