THREAD (to get you prepared for the #IPCC Special Report on 1.5°C #SR15)

What are the origins of 1.5°C?

cicero.oslo.no/en/understandi… 1987: President of the Maldives: "We know, & yet we keep delaying action. The time for just talking is over."
1988: James Hanson testified "99% confidence"
1988: The #IPCC is born
1990: IPCC First Assessment Report (FAR)
1990: Alliance of Small Island States (AOSIS)

Impressive new study on the carbon intensity of crude oil production by field. Average life-cycle emissions are 10.3gCO₂-eq/MJ or 1.7GtCO₂-eq (5% global energy GHG emissions), with huge variation by field / country. 1/5
science.sciencemag.org/content/361/64… ($) Flaring (red), heavy oil (blue), or both (yellow) are key factors increasing emissions. Flaring is 22% of average weighted carbon intensity, but much higher in some places (over 50%). Heavy oil can be very emission intensive, but not always. 2/5

What is the role of oil in a 2°C world?

THREAD on my presentation at #ONS2018 #CentreCourt (Monday), where I (try to) explain why there is potentially space for some new oil & what constrains the amount 1/

slideshare.net/GlenPeters_CIC… It is important to remember, that every molecule of CO₂ that enters the atmosphere causes the temperature to increase. To stop temperature rising, either stop emitting CO₂ or, if you must, take out what you put in. 2/

A #HothouseEarth THREAD

The standard headline & interpretation: We are doomed, the Earth's climate will runaway to 4-5°C even if we slash emissions.

Well, that is not what the paper says (actually, it is a Perspective), & I don't see this framing as particularly helpful! The paper does not seem to define "Hothouse Earth", this seems to come from the press material? I don't see much on 4-5°C or 10-60m in the paper, if so, it is very indirect?

THREAD on the climate sensitivity (& carbon budgets)...

After decades of research, the equilibrium climate sensitivity has remained fairly close to 3°C for a doubling of pre-industrial CO₂ concentrations.

carbonbrief.org/explainer-how-… The range has remained stubbornly wide (1.5°C-4.5°C), despite many individual studies claiming to narrow it (particularly recent instrumental-based methods). Though, @AndrewDessler could argue that in the 1970's the range was underestimated & today it is overestimated (maybe).

This thread seems to get two things wrong
1. Emissions need to be as close as possible to zero AND CO₂ removal is needed in addition (it is not either/or)
2. Mitigation is currently FAR cheaper than removal (removal may help costly mitigation, like air to fuels for aviation)

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If CO₂ removal was used to just offset existing emissions (instead of reducing emissions), it is far cheaper to deploy energy efficiency, solar, batteries, CCS, etc, then recapture emissions directly from air (expensive). Even if social cost was $80/tCO₂, still take cheapest?

THREAD

What are climate scenarios?

We use scenarios to explore the consequences of uncertainties (social, political, technical, climate).

cicero.oslo.no/en/posts/news/… Climate scenarios are generally separated into two categories:
1. Transition risks related to the transition to a lower-carbon economy
2. Physical risks related to the physical impacts of climate change
Both types depend on different tools & methods

THREAD

We need research, development, & eventual deployment of negative emission technologies, but relying on them at scale is an unjust and high-stakes gamble.

science.sciencemag.org/content/354/63… The first part of this sentence means that @KevinClimate & I support the great work of @DKeithClimate & colleagues. The second part pissed many people off, particularly people working on these technologies. science.sciencemag.org/content/354/63…

New study suggests higher economic growth rates more likely than previously thought, making the worst-case emission scenario (RCP8.5) more likely. pnas.org/content/early/… Maybe economic growth will be higher than thought, but that does not translate into RCP8.5 (not sure there is a connection). "We’ve already locked in a certain amount of climate policy” newscientist.com/article/216884…

THREAD: Yes, 1.5°C is possible with low BECCS...

A new @NatureClimate paper from @DetlefvanVuuren & the @IMAGE_PBL team shows that there are alternative pathways to 1.5°C with less negative emissions. (the blue areas get small in the bottom right figure)

nature.com/articles/s4155… The alternative pathways include lifestyle change, additional reduction of non-CO₂ GHGs, & more rapid electrification of energy demand based on renewable energy. Some of these alternative may not be easy to implement, but they are additional tools to add to the toolbox!

THREAD

Is the new Shell Sky scenario a radical pathway to 2°C or just a justification for more fossil fuels?
* Primary energy consumption high
* CO₂ as expected for a "well below 2°C" scenario

#ShellScenarios

cicero.oslo.no/no/posts/cicer… Fossil fuels:
* Coal consumption higher than most 2°C scenarios
* Oil consumption as expected, but high in 2100
* Gas low, but no one knows the role of gas in the future

Bioenergy:
* Higher than IEA, but in line with most other 2°C scenarios

THREAD

Why did CO₂ emissions grow 1.4% in 2017?

Here is the answer according to the @IEA "Global energy and CO₂ status report" Energy demand drives CO₂:
* Energy demand grew by 2.1% in 2017, more than twice the rate in 2016
* 70% of the growth in (primary) energy demand was due to fossil fuels
* Renewables had similar growth to 2016, but a smaller share of the total increase in energy (25%)