Friday, I ended a diary on the possible criminal investigation of Shell Oil’s Arctic drilling ship, Noble Discoverer, with a “side note,” describing my frustration that more and more, I feel less certain humans are capable of avoiding a climate catastrophe that might even turn into an extinction event, or something akin to the effects of the Toba eruption, about 70,000 years ago.

In Antarctica, a relatively small ice sheet, Pine Glacier, and an undersea rock, throttle back the galloping movement of Thwaites Glacier. Were the throttling to stop, Penn State Prof. Richard Alley observed at a conference earlier in February, “if Thwaites Glacier in Antarctica were to cease being pinched or grounded its surge would raise sea level by three meters.