Thread by @ClimateBen

Remember:

1. We're now reaching 420 ppm of CO2 with methane & nitrous oxide levels also rising

2. It's likely we'll be over 350 ppm for centuries: calamity

3. We face dire 1.5°C of global warming before 2030 and risk hellish 2.3 - 2.8°C by the 2040s

4. We can and must act now

Earth's ice is melting. Global food security is at risk. Emissions must stop as soon as humanly feasible. A global anti-imperialist movement to stop wars and shift to a postgrowth economy could slash emissions fairly towards zero in rich countries by 2030.phys.org/news/2020-08-e…

Emissions will likely rise in the coming 18 months. It's hard to convey how terrible this is. Corporate media naturally downplay or ignore the severity.

'projections for 2021 show emissions..on a rising path. Next year there could be even stronger rises'.dumptheguardian.com/environment/20…

Major methane sources:

Wetlands
Agriculture (cows, ...)
Fossil Fuels
Landfills

and Permafrost (now or very soon)

'researchers haven't found evidence that methane is leaching in significant amounts from the warming Arctic — not yet, anyway.' mashable.com/article/methan…

Nitrous oxide emissions are:

'increasing faster than any scenario predicted by experts'

'consistent with scenarios where the global mean temperature would rise by 3C from pre-industrial levels.'

We must replace industrial agriculture with agroecology. irishnews.com/magazine/scien…

We hit 350 ppm in the 1980s.

We must get back below 350 ppm for any kind of reasonable chance of safety according to James Hansen (who remains hopeful). And that ought to happen rapidly this century but that kind of timescale now seems beyond us.

Thread:

https://twitter.com/ClimateBen/status/1387083313706373123?s=20

If emissions keep rising this decade, 2C by the 2030s/40s and 3C by the 2050s/60s looks a likely scenario. Unthinkable horror.

If we cut emissions fast, as we must, the unmasking of the aerosol effect will add warming.🔥

Can we delay 2.5-3C? See here:

independent.co.uk/climate-change…

Our food systems are now at risk as the climate-extinction crisis builds dramatically. See this thread for details:

https://twitter.com/ClimateBen/status/1399703027561422849?s=20

'Temperatures are expected to pass 2C in the modest-mitigation SSP2-4.5 scenario between 2038 and 2072' (median year 2052)

higher emissions SSP3-7.0 scenario: 2C between 2035 and2058 (median 2048)

SSP5-8.5 scenario: 2C between 2034 and 2052 (median 2043)carbonbrief.org/analysis-when-…

Committed warming seems set to take us to +2.5C eventually (though not all scientists agree on this).

But hellish 2.5-3C is possible by mid-century:

'There is a 50% probability of 2.4 –2.6 °C warming in the near term (2050) and 4.1–5 °C warming by 2100.'pnas.org/content/114/39…