After dropping 5.4% in 2020, global fossil CO₂ emissions are expected to increase 4.9% [4.1-5.7%] in 2021, finishing just 0.8% below 2019 emission levels.
Coal & gas are now back above their pre-pandemic (2019) levels, while oil remains suppressed.
Assuming oil returns to 2019 levels in the next year or two, a drop in coal use is required to avoid further emissions growth.
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China grew in 2020 & especially 2021, now with solid growth since 2016.
Other major countries had a rebound which puts them back on their decade trends.
The recovery is also uneven across smaller countries (all others).
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Our projections are the hard work of @robbie_andrew & @jikorsbakken, who use monthly energy data to estimate emissions & then project forward for the months without data.
This means we have estimates by coal, oil, gas, & cement for major emitters.
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This year there was a major update of CO₂ emissions from land-use change, mainly in Brazil.
Land-use change emissions now trend downwards in the last decade instead of trending upwards in the earlier budgets (dotted line).
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In the @gcarbonproject, we update all the data every year (come on, seriously, you think we just add an extra year?).
With the new land-use data, total emissions are now flat in the last decade.
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The revised LUC data does not help keep RCP8.5 alive, unfortunately (?).
Now total CO₂ emissions are clearly deviating from high-end emission pathways (this was not the case previously).
All these CO₂ emissions lead to an increase in the atmospheric concentration of CO₂, which are estimated to reach 415 parts per million (ppm) this year.
@robbie_andrew uses available observational data & projects for the rest of the year using the seasonal cycle.
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In the last decade, the atmospheric CO₂ increase has averaged ~2.4ppm.
Even though emissions dropped 5.4% in 2020, CO₂ increased 2.4ppm.
In 2021 emissions went up 4.9%, but CO₂ may increase only 2.0ppm.
You may have heard that after revisions to land-use change emissions, total global CO₂ emissions are approximately flat over the last decade (black line).
But, how much do we revise carbon budget components each year?
Let's have a look...
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Fossil CO₂ emissions are revised each year, particularly the last decades. We update data & improve methods. Chinese data has had major revisions & cement was completely revised in 2018, plus lots of smaller improvements.
Land-use change (LUC) emissions are much more uncertain:
* 2014-2015: one bookkeeping model used
* 2016-2019: two bookkeeping models used
* 2020-2021: three bookkeeping models used
* 2021: major update of land-use forcing (change) datasets
"Everyone wants to keep the dream of 1.5°C alive. In every practical sense you are kidding yourself if you think that we are remotely heading towards 1.5°C"
The UNFCCC Synthesis Report says NDCs will lead to a 5% rise in emissions from 2019 to 2030. This is 16% above 2010 levels, as opposed to ~50% below as required for <1.5C. unfccc.int/news/updated-n…
If global CO₂ emissions stay at net zero, either:
* All countries need to be net zero ~2050, or
* Rich countries have net negative emissions post-2050, allowing developing countries to emit longer post-2050.
"Instead of leaving such work to volunteers, global institutions should marshal the funding & expertise to collect crucial data, & mandate their publication"
💯agree with @_HannahRitchie. No one wants to fund the giant who's shoulders we stand on.
The approach to science is to fund big models, expensive observations, etc. All this is needed, but somehow science seems to have forgotten the importance careful curation & maintenance of data.
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Science is full of projects that improve models, do model comparisons, process some satellite data, etc, & if you are lucky there might be a task that scrapes together some data to feed the models.
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