Achieving total decarbonisation

In the run-up to the UN Climate Change Conference (COP21) in Paris, more than 150 governments submitted plans to reduce carbon emissions by 2030. Many observers are asking whether these reductions are deep enough. More importantly, whether the chosen path to 2030 shall provide the basis for terminating greenhouse-gas emissions later in the century. According to scientists, climate stabilisation requires full decarbonisation of the energy systems and zero greenhouse-gas emissions by around 2070.
Yet the issue of decarbonisation is not being negotiated by countries at COP21. They are negotiating much more modest steps, to 2025 or 2030, called Intended Nationally Determined Contributions (INDCs). The US INDC, for example, commits to reduce CO2 emissions by 26-28 per cent by 2025.
Though the fact that more than 150 INDCs have been submitted represents an important achievement of the international climate negotiations, most pundits are asking whether the sum of these commitments is enough to keep global warming below the agreed limit of 2.0 degree celsius (3.6 degree Fahrenheit), i.e., temperature of pre-industrial revolution period.  
Another important question (justifiably so) that has surfaced is whether countries will achieve their 2030 targets in a way that helps them attain zero emissions by 2070 (full decarbonisation). The critical issue, in short, is not 2030, but what happens afterwards.
We know that the simplest way to reduce emissions to 2030 is by converting coal-fired power plants to gas-fired power plants. The former emit about 1,000 grams of CO2 per kilowatt-hour; the latter emit around half of that. But the problem is that gas-fired power plants and more efficient internal-combustion vehicles are not nearly enough to get to zero net emissions by 2070. According to experts, deep decarbonisation requires not natural gas and fuel-efficient vehicles, but zero-carbon electricity and electric vehicles. A more profound transformation, this offers the only path to climate safety. By shifting from coal to gas, or more efficient gas-burning vehicles, the world falls in to a high-carbon trap.
The lure of the short-term fix is very powerful, especially to politicians. In order for policymakers to understand what is really at stake in decarbonisation, and therefore what they should do today to avoid dead-end gimmicks and facile solutions, all governments should prepare commitments and plans not only for 2030 but also at least for 2050.
This is the core message of the Deep Decarbonisation Pathways Project (DDPP), which has mobilised research teams in 16 of the largest greenhouse-gas emitters to prepare national Deep Decarbonisation Pathways to mid-century. The DDPP shows that it is technically feasible and affordable, and it has identified pathways to 2050 and put the major economies on track to full decarbonisation by around 2070.
Experts have advanced the above propositions. The path of full decarbonisation should be pursued for all intents and purposes. Only the deep-decarbonisation pathway gets the economy to the necessary stage by 2050 and to zero emissions by 2070.
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