Time will run out to prevent 2°C warming barrier being breached

I have a number of times referred to a graphic “Figure 2 Summary of Results” produced by the UNFCCC for the Paris COP21 Climate Conference in December 2015. It was a centerpiece of the UNFCCC Synthesis report on the aggregate effect of INDCs.

The updated graphic (listed as Figure 2, below the Main Document pdf) is below

This shows in yellow the impact of the INDC submissions covering the period 2015 to 2030) if fully implemented against limiting warming to 2°C  and 1.5°C . This showed the gulf between the vague policy reality and the targets. Simply put, the net result of the INDCs submissions would insufficient for global emissions to peal Yet in reaching an “agreement” the representatives of the entire world collectively put off recognizing that gulf.

For the launch of the UNIPCC AR5 synthesis report in 2014, there were produced a set of slides to briefly illustrate the policy problem. This is slide 20 of 35, showing the  reduction pathways.

 

The 2°C  of warming central estimate is based upon total GHG emissions in the 21st Century being around 2500 GtCO2e.

At the launch of 2006 Stern Review Sir Nicholas Stern did a short Powerpoint presentation. Slide 4 of the PDF file is below.

 

The 450ppm CO2e emissions pathway is commensurate with 2°C  of warming. This is based upon total GHG emissions in the 21st Century being around 2000 GtCO2e, with the other 500 GtCO2e presumably coming in the 22nd Century.

The UNFCCC Paris graphic is also based on 2500 GtCO2e it is also possible to calculate the emissions reduction pathway if we assume (a) All INDC commitments are met (b) Forecasts are correct (c) no additional mitigation policies are enacted.

I have produced a basic graph showing the three different scenarios.

The Stern Review assumed global mitigation policy would be enacted around 2010. Cumulative 21st Century emissions would then have been around 450 GtCO2e. With 500 GtCO2e allowed for post 2100, this gave average emissions of around 17 GtCO2e per annum for the rest of the century. 17 GtCO2e, is just under 40% of the emissions in the year the policy would be enacted.

IPCC AR5  assumed global mitigation policy would be enacted around 2020. Cumulative 21st Century emissions would then have been around 950 GtCO2e. A presentation to launch the Synthesis Report rounded this to 1000 GtCO2e as shown in slide 33 of 35.

Assuming that global emissions were brought to zero by the end of the century, this gave average emissions of 20 GtCO2e per annum for the rest of the century. 20 GtCO2e, is just under 40% of the emissions in the year the theoretical global policy would be enacted. The stronger assumption of global emissions being reduced to zero before the end of the century, along with a bit of rounding, offsets the delay.

If the Paris Agreement had been fully implemented, then by 2030 cumulative 21st Century emissions would have around 1500 GtCO2e, leaving average emissions of around 14 GtCO2e per annum for the rest of the century. 17 GtCO2e, is just over 25% of the emissions in the year the policy would be enacted. The failure of the Paris Agreement makes it necessary for true global mitigation policies, if in place by 2030, to be far more drastic that those of just a few years before to achieve the same target.

But the Paris Agreement will not be fully implemented. As Manhatten Contrarian (hattip The GWPF) states, the US was the only major country proposing to reduce its emissions. It looks like China, India, Indonesia, Russia and Germany will all increase their emissions. Further, there is no indication that most countries have any intention of drastically reduce their emissions. To pretend otherwise is to ignore a truism, what I will term the First Law of Climate Mitigation

To reduce global greenhouse gas emissions, the aggregate reduction in countries that reduce their emissions must be greater than aggregate increase in emissions in all other countries.

Modeled projections and targets are rendered meaningless if this truism is ignored. Yet this is what the proposers of climate mitigation policy have been effectively doing for many years. Emissions will therefore breach the mythical 2°C warming barrier, but based on recent data I believe warming will be nowhere near that level.

Kevin Marshall

 

 

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  1. Daniel Hannan on the selfishness of running a deficit and post-truth realities | ManicBeancounter

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