Month: December 2021

Enlarge / A human relative left these five tracks in a 3.6 million-year-old layer of sediment at the Laetoli Fossil site in Tanzania. (credit: McNutt et al. 2021)

The first evidence of human relatives walking on two feet comes from about 70 footprints left by at least two Australopithecus afarensis walking across soft volcanic ash about 3.6 million years ago. A. afarensis was a short hominin with a jutting lower jaw, which walked upright but may also have spent some time in the trees; the most famous member of the species is a fossil woman now called Lucy.

Not far from that site, another set of footprints reveals that Lucy and her kin may have lived alongside another bipedal hominin species, one that moved very differently.

The forgotten footprints

When the footprints were first spotted in 1976, the paleoanthropologists who unearthed them from what's called Site A weren't sure what to make of them. Paleoanthropologist Mary Leakey suggested they could be hominin tracks, but others weren't so sure. One anthropologist even suggested the tracks could have been left by a young bear walking on its hind legs for a few steps.

Enlarge / Footprints made out of fresh green grass on a dry cracked earth base. (credit: Hype Photography / Getty Images)

Carbon taxes can attract a lot of flak. On one hand, some groups hate taxes and are indifferent to climate change—in Canada, various provincial governments actively fought (and ultimately lost) against the federal government’s implementation of a carbon levy. On the other hand, some progressives worry that a carbon tax would hurt lower-income people by costing them more money.

According to new research, however, this doesn’t need to be the case. Noah Scovronick, a researcher at the Gangarosa Department of Environmental Health at Emory University and one of the paper’s authors, said that it’s possible to help reduce emissions while also implementing a carbon tax that redistributes wealth to people on the lower side of the socioeconomic spectrum.

And that's good news, as carbon taxes are already in use. According to the World Bank, in 2020, around 40 countries and 20 cities, states, or provinces already have some kind of carbon-pricing mechanism. The United States has, occasionally, mulled over the idea of implementing one itself. “[It] does have a history in terms of being endorsed by a number of politicians and/or economists as a sort of—I don’t want to say straightforward—but one of the potentially more straightforward ways you could approach emissions reductions,” Scovronick told Ars.