Recently I reviewed how the 2019 IEA scenarios show the world is markedly diverging from IPCC no climate policy scenarios expecting >3˚C warming. Is this a fresh development reflecting a sudden new reality or has the world been following this path for a while? Thread: 1/13 
👆 Looking at CO2 emissions from all the IEA current policy and announced policy scenarios since the last IPCC assessment a few things are clear - 2/13
(1) IEA has shown that the world’s current policies have been tracking well below the median IPCC no climate policy scenario since 2012. Though the new 2019 Current Policies Scenario is the first year to align with the baseline lower bound ↓ so that is a new development - 3/13
(2) However, stated polices have had us tracking in line or below the no climate policy lower bound since 2012, so there is no clear evidence that recently announced climate policies as modeled by the IEA are having a notable impact here - 4/13
Is this energy and climate policy reality factoring into the no climate policy scenarios informing the next IPCC assessment? Not really. - 5/13
The median SSP database no policy scenario is lower than AR5, and therefore it is better aligned with the IEA Current Policy outlook so that's a positive development - 6/13
But the SSP baseline range is produced by a smaller set of energy models than used in AR5, so it is unclear at this point how much the full IPCC WGIII set of no climate policy baselines will have shifted from the 5th to the 6th assessment - 7/13
Notably, there are still many outlooks for fossil fuel CO2 emissions >50% ⬆️ in 2040 from where the IEA shows the world heading - 8/13
No policy baselines should provide a useful counterfactual, and a roadmap to design effective policies ➡ important to consider factors that may lead IEA to underestimate emissions, but do scenarios so widely divergent still have scientific and policy relevance? - 9/13
When we add up all the cumulative fossil fuel and industry CO2 emissions from 2005 to 2040 in the IPCC 5th Assessment scenarios the divergence is even starker - 10/13
IEA modeling is suggesting that with no additional policies we’d still align with many of the IPCC scenarios expected to result from moderate and strong mitigation policy in both AR5, and in the SSP scenarios that will inform the next IPCC assessment - 11/13
And if we focus in: where do cumulative emissions sit compared to the CMIP6 scenarios used for climate model experiments? Once again, the IEA scenarios are aligned with the scenarios consistent ➡️ 2040 with RCP2.6 to RCP4.5 - 12/13
So next time you hear someone saying business-as-usual has us heading >4˚C, or that we’re far off from 2˚C, you can always cite this thread as evidence to the contrary ⬆️ 👍 Although that doesn’t mean we don’t still have a lot of work to do after 2040 for <2˚C - 13/13
Technical Footnote: IEA scenarios shown above do not explicitly include an accounting of industrial emissions, I’d be glad to add industrial emissions if someone can provide a time series but as the figures note definitions are not aligned across other energy models shown either
