Antarctic Tipping Point

Robert Hunziker reports on research into the stability of the Thwaites and Pine Island glaciers. He quotes an article published in The Cryosphere.

Mass loss from the Antarctic Ice Sheet is the main source of uncertainty in projections of future sea-level rise, with important implications for coastal regions worldwide. Central to ongoing and future changes is the marine ice sheet instability: once a critical threshold, or tipping point, is crossed, ice internal dynamics can drive a self-sustaining retreat committing a glacier to irreversible, rapid and substantial ice loss.

Thwaites' "pinning points" are being undermined by warm currents. It's collapse threatens the entire West Antarctic Ice Sheet and could lead to a 3 meter sea level rise.

Update (June 13):  A study published in Science Advances finds the breakup of the ice shelf protecting the Pine Island glacier is accelerating.

[Our] data show a >12% speedup over the past 3 years, coincident with a 19-km retreat of the ice shelf. We use an ice-flow model to simulate this loss, finding that accelerated calving can explain the recent speedup, independent of the grounding-line, melt-driven processes responsible for past speedups. If the ice shelf’s rapid retreat continues, it could further destabilize the glacier far sooner than would be expected due to surface- or ocean-melting processes.

Update (December 13):  Satellite images presented at the American Geophysical Union meeting show cracks across the ice shelf protecting the Thwaites glacier. The shelf could shatter into hundreds of icebergs within three to five years.

Update (December 17):  Robert Hunziker reiterates how precarious the situation is.

Once the ice shelf collapses, it’ll lead to massive "ice cliff collapsing," ongoing collapse of towering walls of ice directly overlooking the ocean that crumbles into the sea. And, once ice cliff collapsing starts, it will likely become a self-sustaining "runaway collapse."

[T]he biggest unknown in this grisly affair is timing, assuming Thwaites does collapse within a decade, how soon will ice cliff collapses bring on sea level rise that drowns the world’s coastal metropolises?

Satellite images from 2015 and 2021:

Update (June 12, 2022):  A paper published in Nature Geoscience finds that Antarctic glaciers are retreating at the fastest rate in 5500 years. Ted Scambos explains why the flow rate for Thwaites has doubled in the past 30 years.

Update (September 6, 2022):  A study published in Nature Geoscience finds that the Thwaites glacier has retreated very quickly in the past and could do so again.

Update (September 7, 2022):  Matthew Rozsa reports on the Thwaites study and a Greenland study.

Extreme Drought

As the carbon dioxide concentration reaches it's highest level in 3.6 million years, much of the western United States is on the verge of a permanent drought.

Update (April 17):  Decreased flow in the Colorado River may prompt the U.S Bureau of Reclamation to declare an official water shortage for Nevada and Arizona.

Declining Church Membership

Amanda Marcotte notes that the failure to recruit younger generations has resulted in a steep drop in religious affiliation in the past couple decades. The trend in Gallup polls shows 73 percent participation in 1937, 71 percent in 1975, 70 percent in 1999, but only 47 percent by 2020.

It's a story with a moral so blunt that it could very well be a biblical fable: Christian leaders, driven by their hunger for power and cultural dominance, become so grasping and hypocritical that it backfires and they lose their cultural relevance. ... [I]t's undeniable that this decline is tied up with objectively good trends: increasing liberalism, hostility to bigotry, and support for science in the U.S.

Update (April 3):  While "creeping secularism" might be pushing the religious right toward increasingly anti-democratic views, John Stoehr argues it's a mistake to view secularization as being opposed to religion.

The same person can be religious and secular at the same time. Secularization is not, or should not, be a goal in and of itself. It is a means, rather, to an end, namely liberty.

I suspect many [non-religious liberals] believe religion itself is the problem, and they believe this, because they have accepted uncritically what the zealots themselves believe when they say the only way to be a religious person is by first being a conservative person.

All religions have liberal traditions. They may be buried. They may have been silenced. But they are there. More importantly, for liberals, is that these traditions be given oxygen, which is to say, be given the freedom they need to thrive. For the zealots, the point of religion is not doing unto others as you would have done unto you. It is not bringing the greatest good to the greatest number. It's about dominance. To the extent the liberals know this, it's from the inside of the zealots' preferred view, which means they are fighting against freedom even as they fight for a secularized America.

A secular society is not one in which religion is absent. A secular society is one in which there is enough room for the vast varieties of religious feeling to be expressed openly and safely, inside and outside the realm of politics. Liberals should pursue religious diversity with the same oomph with which they pursue racial diversity. With enough time and effort, perhaps religion will stop being a byword for conservative. That would be good for religion. That would also be good for American politics.