9. It seems 1.5°C has come down to semantics, "virtually impossible" versus "challenging"?
I see my job as a scientist to be frank on the challenges, but to doomsdayers, noting the challenges is not the same as giving up. Still plenty to fight for. cicero.oslo.no/no/posts/klima…
/end
Bonus tweet 1: I think the scientific community has done itself a disservice with framing carbon budgets as single numbers with a probability (eg 475 GtCO₂ for a 66% chance).
Better to use ranges (eg 760 GtCO₂ with 33–66% range 475–930 GtCO₂). rdcu.be/bHT2C
Bonus tweet 2: Using a single number gives a false precision, & leads to the "12 years to..." framing.
A range explicitly brings in the uncertainty, & allows more nuance to be given on the feasibility of 1.5°C. This would avoid much of this thread...
Bonus tweet 3: Here is the 5-95% temperature uncertainty for 1.5°C scenarios from two simple climate models (FAIR, MAGICC) used in SR15. The peak temperature ranges from 1.1°C to >2°C.
If FAIR is correct, 1.5°C is not 'virtually impossible'...
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Record high emissions means record high radiative forcing.
We have you covered, we also include aerosols (SO2, etc) & have done so for decades. Also shipping!
Short-lived aerosols are important, but should not distract from the drivers of change: greenhouse gas emissions!
2/
Most of the energy put into the system ends in the ocean (90%), so the Ocean Heat Content (OHC) has been increasing along with emissions and radiative forcing.
This also means the Earth Energy Imbalance is also increasing.
This question is ambiguous: "How high above pre-industrial levels do you think average global temperature will rise between now and 2100?"
* ...pre-industrial... between "now and 2100"?
* Where we are currently heading or where we could head? This is largely a policy question?
3/
One of the key arguments that Norway uses to continue oil & gas developments, is that under BAU it is expected that oil & gas production will decline in line with <2°C scenarios, even with continued investment.
Let's look closer at these projections & reality...
1/
Here is the projections from the 2003 report from the petroleum agency.
In reality (tweet 1) there was a dip around 2010, but production is now up around 250 million cubic again.
The forecast was totally & utterly WRONG!
2/
In 2011 there was a forecast for an increase in production to 2020, but then a decline. This is probably since they started to put the Johan Sverdrup field on the books.
The increase in production was way too low, again, they got it wrong.