Glen Peters Profile picture
Oct 7, 2021 10 tweets 4 min read Read on X
It is a top day for a top ten day...

We often do plots of the top emitters, especially for fossil CO₂ emissions. But, what about other GHGs? Is it the same distribution of top emitters?

We need a thread for that...

(I know about per capita, so no need to @ me)

1/
CO₂ emissions from net LUC (one bookkeeping model). These are net numbers, some countries are net sources, others net sinks.

Current LUC sources are concentrated in several developing countries (the rich countries cut their forests down long ago).

2/

agupubs.onlinelibrary.wiley.com/doi/full/10.10…
Don't over interpret the LUC numbers.

Different LUC datasets give different numbers. Here is the FAO data (from 2020). Indonesia is much less important in this dataset, Brazil dominates.

There is a lot of uncertainty at the country level, so be careful.

3/
Just to emphasise the uncertainty is large, here are several estimates at the global level. Uncertainty at the country level is much larger...

There are also major definition issues with LUC, which you can read about here carbonbrief.org/guest-post-cre…

Take care!

4/
Ok, if I add the fossil CO₂ emissions to the LUC CO₂ emissions, from Houghton and Nassikas, there are changes in ranking (Brazil and Indonesia mainly).

Just to note the obvious, this change is much less with the FAO data, so the ranking is not robust.

5/
Let's get to something easier...

The top 10 for CH₄ emissions. Many developing countries move up onto the top 10 list, indicating a much larger share of agriculture in their economies.

6/
Finally, N₂O emissions. Again, developing countries move up the list in comparison to CO₂ emissions.

7/
GHG emissions? You know that is misleading as the GWP is not such a good indicator of climate impacts?

But, here it is, without LUC, as that makes it more uncertain. Only the Top 6, and this is from the UNEP Emissions Gap Report 2020.

8/
By popular demand, here is GHG emissions per person, for the top 6 absolute emitters.

9/
The main point of this thread was to point out the differences with CH₄ & N₂O emissions, which gives more emphasis to developing countries.

Addressing CO₂ emissions from LUC is really hard. It is easy to download a dataset & plot, but this masks the huge uncertainties.

/10

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More from @Peters_Glen

May 9
"Implemented policies result in projected emissions that lead to warming of 3.2°C, with a range of 2.2°C to 3.5°C (medium confidence)"

According to the landmark, widely reported IPCC Synthesis Report published in 2023.


1/ ipcc.ch/report/ar6/syr/
Image
If you are surprised by this figure, where the median is 2.5°C (not 3.2°C), then I am curious why you think scientists are so optimistic...

The survey reflects more or less what scientists have been saying for years?



2/ theguardian.com/environment/ar…
Image
This question is ambiguous: "How high above pre-industrial levels do you think average global temperature will rise between now and 2100?"
* ...pre-industrial... between "now and 2100"?
* Where we are currently heading or where we could head? This is largely a policy question?
3/
Read 10 tweets
Apr 12
There is a very strong linear relationship between atmospheric CO2 (concentration) and cumulative CO2 emissions.

In the last days, quite a few have been commenting there are feedbacks kicking in.

A thread...

1/ Image
If atmospheric CO2 is proportional to cumulative CO2 emissions, then the annual change in atmospheric CO2 is proportional to annual CO2 emissions.

The ratio of the two is the 'airborne fraction', which is rather constant. Maybe a slight increase in trend lately, maybe...

2/ Image
Since emissions have leveled out in the last decade, one would expect therefore that the atmospheric increase has leveled out.

The concentration data is noisy, and it has leveled out or not depending on how it is smoothed! (look at last 10 years).

3/ Image
Read 8 tweets
Apr 9
Is the atmospheric growth rate of CO2 slowing down?

Total CO2 emissions have gone from 2%/yr growth (2000s) to 0%/yr (2010s).

Do we see that change in the atmosphere?

It is hard to answer 🧵



1/ rdcu.be/buifD
Image
I can make this figure incredibly complex by adjusting for ENSO (red dots and line).

We know the response of atmospheric CO2 to El Niño is lagged. This figure shows a 9 month lag, as used by Betts & Jones in their projection

But, 2023 is a La Niña?

2/ metoffice.gov.uk/research/clima…
Image
The same figure with a three month lag says 2023 is a El Niño.

In either case, adjusting the growth rate for ENSO makes it look like the atmospheric CO2 growth rate is maintained, and not slowing down.

This is worrying. It should be slowing down...

3/ Image
Read 8 tweets
Dec 15, 2023
One of the key arguments that Norway uses to continue oil & gas developments, is that under BAU it is expected that oil & gas production will decline in line with <2°C scenarios, even with continued investment.

Let's look closer at these projections & reality...

1/ Image
Here is the projections from the 2003 report from the petroleum agency.

In reality (tweet 1) there was a dip around 2010, but production is now up around 250 million cubic again.

The forecast was totally & utterly WRONG!

2/ Image
In 2011 there was a forecast for an increase in production to 2020, but then a decline. This is probably since they started to put the Johan Sverdrup field on the books.

The increase in production was way too low, again, they got it wrong.

3/ Image
Read 9 tweets
Dec 5, 2023
📢Global Carbon Budget 2023📢

Despite record growth in clean energy, global fossil CO2 emissions are expected to grow 1.1% [0-2.1%] in 2023.

Strong policies are needed to ensure fossil fuels decline as clean energy grows!



1/ essd.copernicus.org/articles/15/53…
Image
CO2 emissions by fossil fuel:
* We thought coal peaked in 2014. No, & up another 1.1% in 2023
* Oil up 1.5%, on the back of a 28% increase in international aviation & China, but oil remains below 2019 level. 🤞
* Has the golden age of gas come to an end thanks to Russia?

2/ Image
By top emitters:
* China up 4.0% & a peak this year would be a surprise
*US down 3.0%, with coal at 1903 levels
* India up 8.2%, with fossil CO2 clearly above the EU27
* EU27, down 7.4% with drops in all fuels
* Bunkers, up 11.9% due to exploding international aviation

3/ Image
Read 11 tweets
Nov 3, 2023
Is the new @DrJamesEHansen et al article an outlier, or rather mainstream?

At least in terms of the key headline numbers, it seems rather mainstream, particularly if you remember most headline key numbers have quite some uncertainty!



🧵1/ academic.oup.com/oocc/article/3…
Image
Equilibrium Climate Sensitivity of 4.8°C ± 1.2°C

IPCC best estimate 3°C
IPCC likely range: 2.5-4°C
IPCC very likely range: 2-5°C

Sure, Hansen et al are in the high end, but so are many others.

More details:

2/
Image
"...global warming will exceed 1.5°C in the 2020s & 2°C before 2050"

Here is the global warming from "Current Policies" in IPCC AR6 WGIII. Sorry folks, but Hansen is actually conservative.

Also, cast your eyes to 2020-2030: WARMING ACCELERATES

3/ Image
Read 7 tweets

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