An Open Thread for Petroleum comments is below this post.
My previous post on an energy transition promised to consider the level of climate change that might be associated with such an Energy Transition. Rather than use Webhubbletelescope’s CSALT model in combination with a simplified Bern Carbon Model, I have chosen to use the MAGICC 6 climate emulator.
Three different values for equilibrium climate sensitivity (ECS) were chosen, with the median of 19 CMIP3 global climate models at 2.88 C based on the analysis (see table B3 on page 1453 of the PDF) of the creators of the MAGICC 6 model. Eighteen of the models have an ECS between 1.9 and 4.15 C, with one outlier with an ECS of 5.5 C, if the outlier is ignored the median ECS is 2.72 C, 73.6% of the models (14 of 19) have an ECS between 2.24 and 3.23 C. Two models are below this range and 3 are above. A description of the MAGICC 6 model can be found at the link provided.
For the chart above, the parameters for the median model are used and only the ECS is changed for the ECS 2.2 and the ECS 3.6 “models” shown in the chart above. The scenario used (RCP4.5b) can be downloaded here.
The Energy Transition scenario was modified from my previous post. Population peaks in 2070 at about 9.15 billion and then declines, so GDP is somewhat lower, the assumption of 1.45% per year per capita real GDP growth remains the same. Energy intensity continues to decline at 1% per year until 2060 and then slows to 0.5% per year, in the earlier scenario energy intensity stopped decreasing after 2050 which was not realistic. I also consider exergy rather than energy and assume coal provides 37% of its primary energy as exergy, natural gas 45%, and oil 30%. Wind, solar, nuclear, hydro, and other (geothermal and biofuels) are each considered separately. After 2025 all non-fossil fuel growth is assumed to be wind and solar power and after 2033 wind and solar grow at 8% per year until 2060. Long term oil and natural gas growth was 7% per year for over 60 years (1910 to 1970 average growth rate in output of oil and natural gas).
The chart above shows the exergy output of these various types of energy in exajoules.
By 2059 all exergy is provided by non-fossil fuels in this scenario and total carbon emissions from all sources (fossil fuels, cement production, land use change, and natural gas flaring) is 939 Pg from 1800 to 2200. The RCP 4.5 scenario is only modified for fossil fuel and other carbon emissions, as well as reducing SOx emissions after 2060 reaching very low levels of about 1 million tonnes of sulfur per year consistent with long term average volcano emissions for the past 200 years.
As a comparison to the scenario above I created an average scenario between the RCP2.6 and RCP4.5 scenarios where the average of carbon emissions (fossil fuel and other) from the two scenarios is used, all other emissions follow the RCP2.6 scenario, a significant difference is the methane emissions are 2 times higher after 2100 in the RCP4.5 scenario. An ECS of 2.88 C is used and total carbon emissions for this “RCP3.6” scenario are 1096 Pg from 1800 to 2200 (160 Pg more than the scenario for the energy transition). Scenario can be downloaded here.
The scenario above changes the methane emissions from the RCP4.5 level to the lower RCP 2.6 level from 2100 to 2250, everything else is unchanged from the initial energy transition scenario. The scenario can be downloaded here.
If we focus on transition from fossil fuels to other types of energy, climate change may be much less of a problem based on the CMIP3 models. The latest GISS Model E2 (CMIP5) also suggests a scenario between RCP2.6 and RCP4.5 may keep global temperatures under 2 C. Keeping global temperature change under 1.7 C may be difficult, if ECS is 3 C, the sooner we get started he better off we will be.