See Ice (or the Lack Thereof)

I hope it's becoming increasingly impossible to ignore the reality of climate change, what with the IPCC report a few weeks ago and the just-released report from 13 U.S. federal bodies summarizing its effects. (Though I thought the first headline I saw from the latter report was laughable: climate change could decrease U.S. GDP by 10 percent by 2100? Wow, if that's all it will do, I wouldn't be worrying about it so much. How about a 90 percent decrease, or perhaps more likely, there won't be a thing called the "United States" at all?)

Maybe you've heard that people in the U.K. are spreading a no-business-as-usual intervention called Extinction Rebellion, shutting down bridges on multiple days in London over the past week or so (and now spreading to Scotland, Manchester, York, and other cities, plus a few on the European mainland). Or maybe you haven't, since the BBC seems to have imposed a news blackout on the topic, though they gave quick coverage to a protest in France about rising gas prices (which is literally the inverse of a climate-change protest).

I don't know about you, but I kind of appreciate new information on climate change that still has the power to startle me. That happened with this graphic, which ran in the Star Tribune yesterday:


The accompanying story was about competition for the new shipping channels that have opened in the Arctic as the sea ice shrinks, but what I got from it was, Holy shit, look at the median sea ice area vs. the area this year.

I had read numbers describing the shrinking ice, but seeing it mapped is a different experience. Here are some words from Carbon Brief on the ice:

Arctic sea ice has reached its summer minimum extent for the year, clocking in at 4.59m square kilometres, which puts it sixth lowest in the 40-year satellite record alongside...

The twelve smallest summer lows in the satellite record have all occurred in the last twelve years....

Satellite data show that Arctic sea ice hit its minimum on two dates this year – 19 and 23 September. The latter is one of the latest dates for the summer low in the satellite record and around 5–9 days later than the 1981–2010 average....

[One scientist is quoted:] "We have lost over half of the summer sea ice coverage since the late 1970’s and it is realistic to expect an ice-free Arctic sea in summer in the next few decades."...

...2018 has seen record low amounts of “multiyear ice” — ice that has survived without melting for multiple years. In the first half of 2018, multiyear ice comprised just 34% of Arctic sea ice, with only 2% at least five years old. In the 1980s, upwards of 60% of Arctic sea ice was multiyear ice. (emphasis added)

Here's that map's data visualized in a different way. In this case, the 30-year average is the gray band and the most recent, warmer years are the various colors:


Oh, and remember, as with all weather data, this graph includes only the 30 most recent years of data — so the increased warming of the 1990s and 2000s is already built into those medians and averages. If we were comparing the recent data to all of the data on record, our recent years would stand out even more starkly.