Thread by @Peters_Glen

THREAD

What will happen to global fossil CO₂ emissions in 2020?

Daily global fossil CO₂ emissions decreased by –17% (–11% to –25%) by early April 2020 compared to 2019.

For January–April emissions fell –8.6% over Jan-Apr 2019 or –2.9% for all 2019.

nature.com/articles/s4155…

2. Emissions for all 2020 depend on future confinement policies:
* low estimate of –4% (–2% to –7%) if ‘normal’ conditions return by mid-June
* a high estimate of –7% (–3% to –13%) if some restrictions remain worldwide for all 2020.

We are not sure what May-December brings...

3. The method is built around a confinement index.

At its peak in April, regions responsible for ~90% of global fossil CO₂ emissions were under some level of confinement.

This approach makes emissions for 2020 easier to estimate using COVID scenarios.

4. On average across different levels of lockdown at the peak in April:
* aviation decreased by 60%,
* surface transport by 36%,
* industry 19%,
* power generation 7%,
* a small increase in residential buildings of 3%

5. Weighting activity levels with sectoral emissions (global):
* Surface transport accounted for almost half (43%) of the decrease in emissions,
* Industry & power together accounted for 43%,
* Aviation ~10%
* Residential led to a slight increase

6. The total cumulative change in emissions until the end of April was –1048 (–543 to –1638) MtCO₂:
* China: –242 MtCO₂ (23% of total change),
* US: –207 MtCO₂ (20%),
* Europe: –123 MtCO₂ (12%),
* India: –98 MtCO₂ (9%)

Country results available, but more uncertain...

7. Climate change is a consequence of cumulative CO₂ emissions & a reduction of global emissions by 5% in one year will have an undetectable effect on global temperature (~0.001°C), but…

8. …there is a lot to learn from the analysis
* Estimates of daily emissions (granular data)
* Effects of policy interventions
* Ways to (& not to) rapidly reduce emissions

9. Emissions will rebound, but how far is highly uncertain:
* How long will COVID be around?
* How elastic will behaviours be as lockdowns weaken?
* How can policy lock-in desirable changes?

We have a lot to learn & humbly admit we don't know what will happen 2nd half 2020...

10. On the more positive side, I sense that fossil fuels will be hit relatively harder compared to renewables. When the economy returns to ‘normal’ we might find that 2019 was peak emissions, with reductions driven by renewables...

11. There are other analyses around, with similar results, though we went the (slower) peer reviewed channel
* @IEA: iea.org/reports/global…
* @DrSimEvans : carbonbrief.org/analysis-coron…
* @hausfath: thebreakthrough.org/issues/energy/…
* @LiuzhuLiu: arxiv.org/abs/2004.13614

Check them out...

12. Carbon Brief will be hosting its first-ever webinar this Thursday (21 May) at 3-4pm UK time.

Topic: What impact is Covid-19 having on global emissions?

Panelists: @richardabetts @clequere @laurimyllyvirta @hausfath

us02web.zoom.us/webinar/regist…

13. Check out the study. It looks open access at the moment, so make the most of it.
nature.com/articles/s4155…

More detailed results at: mattwjones.co.uk/covid-19/

And (online soon): globalcarbonproject.org/news/Temporary…

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