A once in every 7.5 million year event is unfolding in the Antarctic. And it has scientists scrambling for answers
www.abc.net.au
Antarctic sea ice has usually been able to recover in winter. But this time it's different, with levels taking a sharp downward turn at a time of year when sea ice usually forms reliably — and experts are worried.

we’d expect to see a winter like this about once every 7.5 million years.

Unlike 1 in 3000 year floods, we now have 1 in 7,500,000 Winters.

cross-posted from: https://slrpnk.net/post/906853

The article says this:

“The consensus statement at the moment would be that this is largely anthropogenic forces that have caused the ocean to warm, for the atmosphere to be highly disturbed and to affect the sea ice,” she said.

Which means this in terms of gases added to the atmosphere:

IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world. About 1C of total warming. Second chart: about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability. Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases. About 0.5C of cooling with large error bars from SO2.

The key thing about these anthropgenic gases, is that the biggest contribution for CO2, the biggest one, is largely from burning fossil fuels:

Of the total anthropogenic CO2 emissions, the combustion of fossil fuels was responsible for about 64% ± 15%, growing to an 86% ± 14% contribution over the past 10 years. The remainder resulted from land-use change. ___

  • Zagorath@aussie.zoneEnglish
    4·
    1 year ago

    Yeah, 5 sigma is the standard most often used in fields like particle physics. Other fields are usually happy with probabilities much higher than that.