Joeri Rogelj Profile picture
Oct 27 24 tweets 11 min read
Where are global emissions heading and where should they be going to keep #globalwarming well below 2C and 1.5C?

Today, @UNEP released the 2022 #emissionsgap report.

A look at the key messages

but caution, not much good news ahead 🧵/1
Countries’ new and updated pledges (NDCs) submitted since COP26 reduce projected global GHG emissions in 2030 by only 0.5 gigatons of CO2 equivalent (GtCO2e) compared with projections based on pledges at the time of COP26.
Some pledges result in even higher emissions /2
Countries are off track to achieve even the globally highly insufficient NDCs. Global GHG emissions in 2030 based on current policies are estimated at 58 GtCO2e. The implementation gap in 2030 between policies and NDCs is about 3 to 6 GtCO2e. /3
The emissions gap in 2030 is 15 GtCO2e annually for a 2C pathway and 23 GtCO2e for a 1.5C pathway.

This assumes full implementation of the unconditional NDCs, and is for a 66 per cent chance of staying below the stated temperature limit. /4
If, in addition, the conditional NDCs are fully implemented, each of these gaps is reduced by about 3 GtCO2e.

We do know how deeply emissions should be reduced to be on track to limit warming to 1.5C or well below 2C /5
Policies currently in place with no additional action are projected to result in global warming of 2.8C over the twenty-first century. Implementation of unconditional and conditional NDC scenarios reduce this to 2.6C and 2.4C respectively. /6
Depending on what is assumed to happen to emissions after 2030, these projections can be higher or lower by half a degree Celsius. /7
To get on track to keep warming to 1.5C, global GHG emissions in 2030 must be reduced by 45% compared to what policies currently in place deliver, and they must continue to decline rapidly after 2030, to avoid exhausting the limited remaining atmospheric carbon budget. /8
Furthermore, global GHG emissions could set a new record in 2021, rebounding fully from a short slump because of COVID lockdowns. /9
These global GHG emissions are, however, highly uneven between and within countries /10
Total and per capita emissions for major emitters in 2020 /11
Consumption-based GHG emissions per household in 2019 /12
Despite the call for countries to “revisit and strengthen” their 2030 targets, progress since COP 26 is highly inadequate.

Indeed, we see less than 1 GtCO2e improvement in NDCs since Glasgow #COP26, @COP26

Where is Egypt's leadership on this, @COP27P ? /13
G20 members are far behind in delivering on their mitigation commitments for 2030, causing an implementation gap.
In other words, in aggregate, the highly inadequate commitments are even not achieved because of a lack of effective policies /14
Globally, the NDCs are highly insufficient, and the emissions gap remains high /15
If announced net zero targets are achieved global warming could be much lower than the 2.8C implied by current policies.
However, in most cases, neither current policies nor NDCs currently trace a credible path from 2030 towards the achievement of national net-zero targets. /16
“The credibility and feasibility of the net-zero emission pledges remains very uncertain” /17
Important to remember:
Under current policies there remains a 1-in-5 chance that warming ends up beyond 3C until the end of the century, continuing to increase thereafter.
In the best of worlds with all net zero targets there is a similar chance for warming still exceeding 2C /18
Finally, very often the high cost of climate action is mentioned.
We now put these estimates in perspective and show how costs compare to baseline GDP growth and gains achieved by cleaning up the economy and avoiding climate change.
A quite compelling picture if you ask me. /19
In addition to these high level messages, the report also dives deeper into some of the transformations needed to bring GHG emissions down (Chapter 5), the potential for GHG reductions in food systems (Chapter 6) and how to transform the finance system (Chapter 7) /20
If you want to read the entire report, check it out online:
unep.org/resources/emis… /21
As every year, it was a privilege and a pleasure to contribute to this @UNEP initiative and work alongside so many impressive colleagues.
@joanna_portugal @micheldenelzen @tarynfransen @TakeshiKuramo @Kelly_Levin_ and so many others /22
Also a big thank you to the contributing authors on my chapter I was responsible for:
@JKikstra @RobinLamboll @gauravganti @CarlSchleussner @alexkoberle @shivikamittal1 @CleaSchumer /END
Just noticed, it was @schumerclea not @CleaSchumer !
Apologies to both and thanks a lot, Clea!

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More from @JoeriRogelj

Feb 7
Excellent conversation going on about how media messaging following the @IPCC_CH 1.5 report sating we have "12 years left" until [your favorite climate pandemonium term] has been a disservice to science communication, and is damaging to date 👇
(1/n) @guardian @Fridays4future
As one of the coordinating authors of the report I can only wholeheartedly agree with @bobkopp @PFriedling @theresphysics and others that this is a dangerous misrepresentation of the report's assessment and messages.

Let me explain why

(2/n)
Ironically, the "12 year left until climate catastrophe" message (with years being reduced as time passes) is wrong and damaging in two opposite ways:

misrepresentation through exaggeration and driving complacency through inaccurate messaging
(3/n)
Read 12 tweets
Nov 30, 2021
Two years ago - we published a new scenario logic to avoid risky and unfair climate change scenarios in @Nature.

Yesterday, two new studies in @NatureClimate apply this logic and find that avoiding overshoot is the right thing to do both to reduce risks and overall costs.
/1
Our initial @Nature study highlighted that focussing on a target in 2100 and not caring about what happens until then results in scenarios that suggest the best way to meet a target is to plan to first miss it.

Weird, irresponsible, and arguably wrong.
/2

nature.com/articles/s4158…
I explained this logic and its implications further in a long 🧵at the time:

and also in this @CarbonBrief post on how to avoid risky and unfair scenarios.

/3

carbonbrief.org/guest-post-how…
Read 9 tweets
Nov 13, 2021
#COP26 is concluding after two years of work with some important decisions.

Some highlights of those areas I have followed most closely:
1) science
2) increased ambition
3) the Paris Rulebook

Some quick reflections (1/n)
1) science
For the first time ever, scientific evidence is included as a key framing of the various COP decisions. This is historic and includes strong messages on the scientific requirements as identified by @IPCC_CH to keep warming to 1.5C.
(2/n)
It includes required emissions reductions of -45% by 2030, and the need of reaching net zero.

The one bitter pill here is the last minute change from a "phase-out" to a "phase-down" of unabated coal power - very uncool and irresponsible
(3/n)
Read 11 tweets
Nov 10, 2021
New #COP26 analysis: 🚨🌡️🌍
Is COP26 on track to keep 1.5°C alive?

Here I connect the dots between findings of the most recent scientific reports and look at what current pledges mean for carbon budgets limiting warming to 1.5C

(1/n)
I start with historical CO2 emissions from the Global Carbon Project @gcarbonproject as assessed in the latest @IPCC_CH #AR6 #ClimateReport

About 2400 billion tonnes of CO2 (GtCO2) have already been emitted between the years 1850 and the end of 2019 (2/n)
I then add global emissions pathways consistent with current policies, and various interpretations of country pledges (called NDCs, or nationally determined contributions) from the latest update of the @UNEP #EmissionsGap Report 2021. (3/n)

wedocs.unep.org/bitstream/hand…
Read 10 tweets
Nov 2, 2021
Often misunderstood, even by climate change scholars like @jasonhickel, a 2050 #netzero greenhouse gas emissions is not the global average!

It is two decades earlier than the global average in 1.5C pathways. (1/2)
1.5C pathways with no or limited overshoot reach #netzero CO2 emissions by 2050, and #netzero greenhouse gas emissions around 2070.

A target of #netzero GHG by 2050, like the EU, US, UK, and others, is thus well in advance of the global average.
This year's @UNEP #emissions report gives an overview of global timings of net zero CO2 and total greenhouse gas emissions.

Note the difference of about two decades between the timing of global #netzero CO2 and total GHG emissions. Image
Read 4 tweets
Nov 2, 2021
What makes a good #NetZero pledge?

Many things but picking three:
1) focus on reductions then removals (& separate them out)
2) justify how it is fair and adequate
3) have a clear plan showing how reductions are achieved in the near term (1/n)
bbc.com/future/article… @BBC_Future
Together with @CFyson from @climateactiontr and @katecullen_ we comment on how #NetZero targets can help, but also on how there is a series of boxes to be ticked by before any #NetZero target becomes a solid and ambitious contribution to tackling the #ClimateCrisis. (2/n)
Interested in more on #netzero targets?

I wrote a long thread on 10 guidelines that we published earlier this year in the scientific journal @Nature (with Annette Cowie, @ReisingerAndy and @Oliver_Geden) (3/n)

👇👇
Image
Read 4 tweets

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