Oil and gas prices have been skyrocketing in recent months. This is effectively a carbon price – and a pretty high one at $67 per ton CO2 for oil and $62 per ton for gas relative to January 1st 2021 prices – but only as long as prices don't fall: nytimes.com/2021/10/04/bus…
Note that while expensive oil and gas can make clean energy alternatives more cost-competitive, there are real equity impacts on poor households for whom energy is a non-trivial part of their budget.
My assumptions (in case its helpful):
oil_price = 77 - 48. //dollars per barrel
oil_carbon = 0.43080 //tons per barrel
gas_price = 6 - 2.6 //dollars per million btu
gas_carbon = 0.0544311 //tons per million btu
Note that the effective carbon price for coal over the past year is $94 per ton of CO2.
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A number of folks have argued that warming will happen faster than we expect because scientists are not accounting for falling emissions of planet-cooling aerosols as we reduce fossil fuel use. This is not the case – all our future scenarios account for rapid aerosol declines:
Aerosols currently cool the world by around 0.5C (with a fairly large uncertainty). This figure from the recent IPCC AR6 shows the warming since preindustrial times associated with each different factor that contributes to climate change:
In both scenarios consistent with current commitments (SSP2-4.5) and deep mitigation (SSP1-1.9 and SSP1-2.6), cooling from aerosols is cut by 4/5ths, down to ~0.1C by 2100. Most of this reduction happens in the next few decades:
If the proposed Clean Energy Performance Program becomes law it will severely penalize utilities for closing existing nuclear plants. We estimate that closing the Diablo Canyon plant would cost PG&E somewhere between $500 million and $1.5 billion: thebreakthrough.org/issues/energy/…
CEPP awards utilities with a payment of $150 per MWh for an increase in year-over-year clean energy generation of over 1.5 percentage points if the total increase year-over-year exceeds 4 percentage points.
For example, if a utility had 20% of the electricity generation from clean sources in 2022, and increased that to 24% in 2023, they would be eligible for a payment of $150 per MWh for 2.5% (4% minus 1.5%) of their total generation.
We are setting the stage for a lot of confusion given differences in the future warming projections in the IPCC AR6 and the latest generation of models (CMIP6). For example, here are future projections for Norway from CMIP6 (dashed) and scaled to AR6 assessed warming (solid):
Right now most folks doing assessments would use the dashed lines, even though they are inconsistent with the best estimate of warming in the AR6. This is because there is currently not any gridded future warming projections available that are consistent with AR6 assessed warming
The AR6 took a novel (and I think improved) approach to future warming projections. Rather than simply using the CMIP6 mean, they used three different weighted CMIP6 estimates – with weights based model agreement with observed temperatures over the past few decades.
As the world adopts climate policies and the price of clean energy falls, we have and will continue to move away from some of the worst climate outcomes of 4C+ warming. But this should not distract us from our ultimate goal of getting emissions to net-zero thewellnews.com/in-the-news/we…
A decade ago the world seemed on track for a very dark climate future. Global emissions were increasing at 3% per year, China was building a new coal plant every three days, and the idea that emissions could double or triple by 2100 did not seem that far-fetched.
Today things have changed markedly. Global coal use peaked back in 2013, and the International Energy Agency’s (IEA) most recent World Energy Outlook suggests that coal is now in “structural decline.” Global emissions are still increasing, but at a rate of only 1% per year.
For every 1C of warming the world experiences, saturated air contains 7 percent more water vapor on average.
Per the IPCC AR6: "The frequency and intensity of heavy precipitation events have increased since the 1950s over most land area for which observational data are sufficient for trend analysis (high confidence), and human-induced climate change is likely the main driver."
"Event attribution studies and physical understanding indicate that human-induced climate change increases heavy precipitation associated with tropical cyclones (high confidence)."
One under-appreciated finding in the IPCC AR6 is a lot more certainty around future warming.
Previously IPCC only gave "likely" warming ranges (e.g. a 2 in 3 chance of falling in the range). New report gives "very likely" 9 in 10 ranges. Here is a rough like-to-like comparison:
The IPCC AR5 future warming projections were nominally based on the 90th percentile of CMIP5 models, but the assessed range of climate sensitivity was much wider than the range in CMIP5 models, so these were treated "likely" (66th percentile) ranges.
The AR6, on the other hand, bases its warming projections on a combination of observationally-constrained CMIP6 models and a simple energy balance model using the new transient climate response (TCR) and equilibrium climate sensitivity (ECS) values in the report.