Prof. Stefan RahmstorfOct 5, 2023
We do understand the #globalwarming caused by fossil fuels - for four decades it’s been going as predicted.
But we don’t understand the surprise upward leap that is happening now.
And that worries me.
Show threadAlberto CotticaOct 5, 2023
@rahmstorf could it be that models tend to incorporate linearity assumptions by default?
Show threadAnne OminousOct 6, 2023

@alberto_cottica @rahmstorf

yes! why is it surprising that climate change is not linear?
i get that we dont know the exact cause of this dramatic & sudden rise, but i'd guess many assumptions have been made about proportional effects

and ofc, we're carrying more CO2 in the atmosphere than earth ever has... a look at the record shows that historically, it was a much hotter planet when CO2 levels were anywhere near this high. maybe things 'catch up' in fits and starts
https://earth.org/data_visualization/a-brief-history-of-co2/

A Graphical History of Atmospheric CO2 Levels Over Time | Earth.Org

As the most abundant greenhouse gas in our atmosphere, CO2 levels have varied widely over the course of the Earth’s 4.54 billion year history.

Earth.Org
Show threadNatanael ⚠️Oct 6, 2023
@rustoleumlove @alberto_cottica @rahmstorf there's probably cooling effects we haven't modeled in full that are weakening. This may include reduced ice cover having secondary effects and vegetation response to temperatures, etc.
Show threadTrötifant

@Natanael_L

That might be one cause. I just heard that the recent reduction of pollutant emissions (which had a cooling effect) in shipping might now uncover a part of the GHG effects that until now have been kind of hidden/suppressed. So, this demonstrates one of the risks of certain geo engineering methods: If you stop them, you get almost immediately thrown back to the hothouse earth.

@rustoleumlove @alberto_cottica @rahmstorf

Oct 8, 2023 at 8:15amWeb