this post was submitted on 01 Dec 2023
16 points (100.0% liked)

Climate - truthful information about climate, related activism and politics.

7239 readers
468 users here now

Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: 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.

Recommended actions to cut greenhouse gas emissions in the near future:

Anti-science, inactivism, and unsupported conspiracy theories are not ok here.

founded 2 years ago
MODERATORS
silence7@slrpnk.net
16
Why We Won’t Know When We’ve Passed the 1.5-Degree Threshold (e360.yale.edu)
submitted 2 years ago by silence7@slrpnk.net to c/climate@slrpnk.net
4 comments fedilink hide all child comments
you are viewing a single comment's thread
view the rest of the comments
[–] benjhm@sopuli.xyz 2 points 2 years ago

All a bit surreal, because it really isn't a physical threshold - just a diplomatic one, lower than 2ºC (too high to save some islands, deltas, food, ecosystems), and higher than 1ºC (already passed when they wanted a lower target). There was originally some paleoclimatic justification for 2ºC, but not with any precision, these round numbers depend on our definition of degrees as 1% of the range from freezing to boiling water.
Sure the physical climate system includes many tipping points, but their thresholds vary by region and sector and we don't know them with precision. So when you try to integrate risk across projected impacts (result of which depends strongly on value judgements) you get a curve, on which nobody has shown that 1.5 marks a special nonlinearity.
Diplomatic thresholds do matter for our social system, but we should acknowledge these for what they are.
Otherwise it tempts the reaction - ok we failed, world's going to end, let's go have another [conference of the] party.