Quotable (#215)

A life-gripped planet:

By controlling the chemical state of the atmosphere, life has also altered the rocks it comes into contact with, and so oxygenated the crust and mantle of Earth. This changes the material properties of the rocks, how they bend and break, squish, fold, and melt under various forces and conditions. All the clay minerals produced by Earth’s biosphere soften Earth’s crust—the crust of a lifeless planet is harder—helping to lubricate the plate tectonic engine. The wetness of Earth seems to explain why plate tectonics has persisted on Earth and not on its dry twin, Venus. One of the more extreme claims of the Gaia camp, at present neither proven nor refuted, is that the influence of life over the eons has helped Earth hold on to her life‐giving water, while Venus and Mars, lifeless through most of their existence, lost theirs. If so, then life may indeed be responsible for Earth’s plate tectonics. One of the original architects of plate tectonic theory, Norm Sleep from Stanford, has become thoroughly convinced that life is deeply implicated in the overall physical dynamics of Earth, including the “nonliving” interior domain. In describing the cumulative, long-term influence of life on geology, continent building, and plate tectonics, he wrote, “The net effect is Gaian. That is, life has modified Earth to its advantage.” The more we study Earth, the more we see this. Life has got Earth in its clutches. Earth is a biologically modulated planet through and through. In a nontrivial way, it is a living planet.

Quotable (#206)

The only successful war on science is the one waged by the Left.

Chronic Neo-Lysenkoism and other pathologies of the left-dominated academy are patiently detailed by John Tierney. (As the reflexive loop of ideological self-confirmation goes, if you don’t know the broad outlines of this story already, you almost certainly aren’t interested in learning about it.)

Anthropocene

‘The Anthropocene is functionally and stratigraphically distinct from the Holocene’ — a multi-authored paper in, Science — proposes a geological discontinuity, dated recently. Abstract:

Human activity is leaving a pervasive and persistent signature on Earth. Vigorous debate continues about whether this warrants recognition as a new geologic time unit known as the Anthropocene. We review anthropogenic markers of functional changes in the Earth system through the stratigraphic record. The appearance of manufactured materials in sediments, including aluminum, plastics, and concrete, coincides with global spikes in fallout radionuclides and particulates from fossil fuel combustion. Carbon, nitrogen, and phosphorus cycles have been substantially modified over the past century. Rates of sea-level rise and the extent of human perturbation of the climate system exceed Late Holocene changes. Biotic changes include species invasions worldwide and accelerating rates of extinction. These combined signals render the Anthropocene stratigraphically distinct from the Holocene and earlier epochs.

Jason Koebler’s packaging of the findings at Motherboard isn’t bad (although predictably over-emotional).

anthropocene00

It’s on.

Quotable (#125)

Steven Weinberg on whiggish history of science:

… scientific history with an eye to present knowledge is needed by scientists. We don’t see our work as merely an expression of the culture of our time and place, like parliamentary democracy or Morris dancing. We see it as the latest stage in a process, extending back over millennia, of explaining the world. We derive perspective and motivation from the story of how we reached our present understanding, imperfect as that understanding remains.