At COP 21 in Paris, governments agreed to “hold the increase in the global average temperature to well below 2°C and to pursue efforts to limit the temperature increase to 1.5°C”. The inclusion of the 1.5°C temperature limit in the Paris Agreement has taken some researchers by surprise and revealed a substantial research gap: at that time a range of 1.5°C emission pathways was available for assessment by the IPCC, but from only two energy-economic models. Researchers are now filling this gap, by working on more pathways consistent with the long-term goal of the Paris Agreement.
A research conference on October 24 in Brussels revealed for the first time a range of 1.5°C scenarios derived from a larger variety of models. These results are an important milestone in light of the implementation of the Paris Agreement that enters into force on November 4.
The meeting was the culmination of a three-year cooperation between fourteen European research institutions – the ADVANCE project – to develop a new generation of scenarios from Integrated Assessment Models (IAMs), including several improvements to these models.
The conclusion from the ADVANCE Project conference was quite clear: to meet the long term goal of the Paris Agreement, net emissions would need to reach zero by 2050, and then go below zero in the second half of the century. This reinforces the results of earlier Integrated Assessment Models.
Most efforts in the short term should focus on the power sector, which should become carbon free no later than 2050. This would enable further emission reductions in the industry, building and transport sector via accelerated electrification. Enhanced efficiency is a key element of all 1.5°C scenarios to reduce primary energy demand while meeting the growing demand for energy services.
As in the earlier available scenarios, the new scenarios deploy carbon dioxide removal (CDR) technologies in the second half of the century, to compensate for the lack of climate action in the past. Among CDR technologies, models mostly rely on BECCS (bioenergy + carbon capture and storage) to achieve negative emissions. Those technologies, though, are currently available only at pilot scale.
As witnessed in the rapid growth of renewables in the last ten years, policies can provide strong incentives to the private sector to deploy BECCS at large scale, which in the scenarios is phased in by the 2030s. A range of social, legal and legislative challenges related to BECCS however await solutions.
The most important challenge now is implementing the Paris Agreement at the country (local) level. Meeting the Paris Agreement’s 1.5° temperature limit requires increased ambition compared to the earlier 2°C goal, which for example guided policy settings in Europe now for nearly 20 years. Papers are beginning to appear analysing what this means.
One example is an analysis by Climate Analytics, funded by the Finnish SITRA program, which looked at how much the EU and Finland must cut emissions and speed up introducing renewables into the energy mix to be in line with the 1.5°C warming limit in the Paris Agreement.
Research takes time but mitigation actions can’t wait. A new generation of Integrated Assessment Models developed by the ADVANCE project show that the energy sector would emit about 1000 GtCO2 of emissions from 2011 until 2100, which is more than twice the allowable carbon budget for a 1.5°C emission pathway. To reconcile this gap, the CDR technologies mentioned above would need remove at least 500 GtCO2 from the atmosphere over the course of the century.
This means that, on average, at least half of each ton of CO2 emitted between now and 2100 would need to be removed from the atmosphere using CDR technologies. This burden adds to the impacts of present emissions and future global warming on future generations, which are already being felt today in vulnerable countries and are likely to get much worse after 2050.
The results of the ADVANCE project reinforce earlier findings that a further delay in implementing stringent climate policies is something the world cannot afford. A simple step in this direction is to remove fossil fuel subsidies, to avoid wasteful consumption of energy. In oil and coal exporting countries this policy would achieve deeper emission reductions than they pledged in their INDC. To enhance this, “indirect” subsidies should be removed as well. This means that environmental and socio-economic damages (like health) associated with fossil fuel combustion and extraction would be accounted for in the legislative and taxation environment of coal-fired power plants, for instance.
Globally, though, removing fossil fuel subsidies alone is highly insufficient to reach a 1.5°C scenario and a wider set of policies is required. It is critical to phase out coal power plants as soon as possible and to reach 100% renewables by 2050. It is also essential to move towards zero emissions from transport by introducing electric vehicles and through a shift in transport modes towards public transport.
There is no universal recipe for policies to reach these goals. However, lessons can be learned from countries and states that can be seen as climate leaders. Norway and California, for example, are pioneering the transition towards low carbon mobility by introducing subsidies and low carbon quotas.
Introducing a carbon price in the economy would provide a strong long-term signal to the private sector. This can be achieved trough carbon taxes or emission trading schemes. Major emitters like the EU need to reform and strengthen their current emission trading schemes to overcome the low carbon prices due to economic crises and over allocation of emission quotas.
Current policies determine future emissions – and warming, which is heading towards 3.5°C with present policy settings. In Marrakesh negotiations on implementing the Paris Agreement – and thus fundamentally changing this trajectory – will continue.
Important issues include preparation for the examination of the collective ambition of NDCs (Nationally Determined Contributions) in 2018 – how far they are from the 1.5°C emission pathway and what needs to be done to close the gap. The 2018 process is known as the Facilitative Dialogue, and will be supported by an IPCC Special Report on 1.5°C impacts and mitigation. Based on this, governments are meant to submit improved NDCs by 2020.
The results of the ADVANCE Project are a very important scientific input into this process. Bending the curve of global emissions downwards is urgently needed. Let it be sooner rather than later.