There has been pressure recently on the IPCC to upgrade its Sustainable Development Scenario (SDS) to be consistent with 1.5°C, and give it more focus. Is the IEA SDS really so bad? I compare some IEA scenarios to 1.5°C scenarios to understand the differences.

1. Should the IEA do a 1.5°C scenario?
Glen Peters (CICERO Center for International Climate Research, Oslo, Norway)
CICERO Climate Finance – Advisory Board Meeting (CICERO, 29/04/2019)

2. From no policy, to NDCs, to 2°C, to 1.5°C, to…
The plethora of scenarios

3. There are now a new set of scenarios consistent with 1.5°C, in addition to existing 2°C & higher scenarios…
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
IPCC Special Report on 1.5°C

4. Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Without climate policy, temperature >3°C
We live in a world with climate policy, and most studies suggest current policies lead to about 3°C in 2100
There is a large range of baseline scenarios, we just do not know the “baseline” would in the future…
Paris Agreement
pushes emissions down

5. For 2°C, 25% reduction by 2030, net-zero around 2075, around 10GtCO2 (gross) negative emissions by 2100
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
2°C pathways require a radical change
Nationally Determined Contributions
(emission pledges)

6. For 1.5°C, 50% reduction by 2030, net-zero by 2050, around 15GtCO2 (gross) negative emissions by 2100
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
1.5°C pathways are 2°C plus more
Nationally Determined Contributions
(emission pledges)

7. There are some short-term benefits of mitigation as well, reduced local air pollution, new jobs, etc
Source: Rogelj et al 2018; Riahi et al. 2016; IIASA SSP Database; NASA GISS
A lot of pain, not much gain?
Paris pledges
Paris goal
CO2
Benefits
°C
Little gain

8. What is the objective of climate policy?

9. • UNFCCC (1992): Avoid dangerous climate change
• Copenhagen (2009): “below 2°C” (consider 1.5°C by 2015)
• IPCC AR5 (2013/14): 66% probability below 2°C (~RCP2.6)
• Paris (2015): “well below 2°C…pursuing…1.5°C”
– “balance [in GHGs between 2050-2100], [SD & eradicate poverty]”
• IPCC SR15: “below 1.5°C in 2100 with [no or low overshoot]”
– 45% decline in emissions by 2030 (from 2010), net-zero ~2050
• “Activists”: Generally, below 1.5°C without negative emissions
The changing goal posts

10. The Paris text “well below 2°C…pursuing…1.5°C” seems to say between 1.5°C and 2°C, but ambiguous time period…
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
The Paris temperature window
IPCC AR5
IPCC SR15

11. Source: IPCC Special Report on 1.5°C of Global Warming
The IPCC Special Report on 1.5°C

12. The pressure on the IEA

13. • “Make clear that the New Policies Scenario (NPS) is a
business as usual scenario that [leads to 2.7ºC to 3ºC]”
• “Develop an updated, fully transparent, ‘Sustainable
Development Scenario’ (SDS) to reflect … [Paris goals]”
– “make this the central scenario of the WEO”
– “reasonable probability (66%) of limiting warming to 1.5ºC”
– “a longer time horizon (beyond 2040)”
– “conservative approach to negative emission technologies”
– “reflect the latest [falling costs] … of clean technologies”
Joint letter to the IEA (quotes)
Source: IEA

14. • NPS: One could argue too much focus
• SDS: Consistent with ~1.7-1.8°C warming, plus some SDGs
– Stops 2040, conservative on CCS/CDR, ok on solar/wind
• Submitted to IPCC SR15
– ETP2017 “Below 2 Degree Scenario” (B2DS)
– WEO2017 (IEA/IRENA) “Faster Transition Scenario” (66% 2DS)
– (Did not submit the NPS or SDS)
• How does the IEA stack up to other scenarios?
Does the IEA do such a bad job?
Notes

15. The two submitted IEA scenarios are consistent with 1.5°C scenarios with overshoot, but…
…reach ~1.75°C in 2100 due to a low level of bioenergy with carbon capture and storage (BECCS).
Source: IPCC Special Report on 1.5°C of Global Warming
The IPCC Special Report on 1.5°C

16. IEA consistent with 1.5°C until about 2050, but do not model net-negative emissions
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
CO2 emissions

17. IEA consistent with 1.5°C scenarios
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Final energy use

18. IEA consistent with 1.5°C until about 2030, but settles above many 1.5°C scenarios
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Coal use

19. IEA consistent with 1.5°C scenarios to 2050-2060
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Oil use

20. 1.5°C scenarios have a lot of variation, but IEA is certainly not an outlier (it is within the bounds of most scenarios)
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Gas use

21. IEA is consistent with most 1.5°C scenarios
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Non-biomass renewables (wind, solar)

22. IEA is consistent with most 1.5°C scenarios
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Biomass

23. IEA is consistent with most 1.5°C scenarios. The SDS (not shown) has much lower CCS…
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Carbon capture & storage

24. IEA is lower than nearly all 1.5°C scenarios…
Data: IAMC 1.5°C Scenario Explorer (hosted by IIASA)
Bioenergy with carbon capture & storage

25. Summary

26. • Over time climate targets get more stringent
• Paris gives a window between 1.5°C & 2°C
• IPCC SR15 is generally “below 1.5°C with limited overshoot”
• IEA does not have a 1.5°C scenario, but earlier scenarios are
similar to 1.5°C to 2050 but have less negative emissions
• IEA does not seem to favour fossil fuels nor depend on
negative emissions in comparison to other scenarios
• IEA could put more focus on SDS & longer-term pathways
Summary

27. Peters_Glen
cicero.oslo.no
cicerosenterforklimaforskning
glen.peters@cicero.oslo.no
Glen Peters